EA044615B1 - PYRIDO PYRIMIDINES AS H4-HISTAMINE RECEPTOR INHIBITORS - Google Patents

Description

Field of technology to which the invention relates

The present invention relates to new pyrido[3,4-d]nirimidineα derivatives, pharmaceutical compositions containing them, and their use for the prevention and/or treatment of diseases or disorders mediated by the histamine H4 receptor.

Current state of the art

The histamine H4 receptor was identified in 2000 as the histamine receptor. Since its discovery, the histamine H4 receptor has received much attention due to its role as a mediator of allergic and inflammatory processes, among other things.

Efforts to obtain effective histamine H4 receptor inhibitors have increased in recent years, and this research has led to several recent patent applications claiming pharmaceutical compositions for the treatment of disorders and diseases mediated by this receptor.

Documents WO 2009/083608, WO 2010/146173 A and Smits et al., J. Med. Chem. 2008, 51, 7855-7865 disclose quinazoline compounds having activity as histamine H4 receptor inhibitors.

In particular, WO 2009/083608 describes the synthesis and H4 binding affinity of quinazoline compounds of the following formula

where R1 is a sulfonamide-substituted alkylamine.

Similarly, Smits et al. (J. Med. Chem. 2008, 51, 7855-7865) disclose an inverse agonist of the H4 histamine receptor with the same quinazoline backbone, and wherein R1 may be differently substituted amino groups.

Finally, WO 2010/146173 relates to the H4 receptor binding activity of certain compounds with a primary amine group at position 1 and a piperazine ring at position 4 of the quinazoline backbone.

However, there still remains a need to find new and effective compounds for the treatment of diseases or disorders mediated by the H4 histamine receptor.

The essence of the invention

The present inventors have discovered that the compounds of formula (I) exhibit activity as histamine H4 receptor antagonists and are therefore useful in the treatment of disorders and diseases mediated by this receptor.

These compounds represent a new pyrido[3,4-th]pyrimidine scaffold whose antihistamine activity has never been discovered. In addition, as described in the experimental section, the present inventors have found that these compounds are not only effective H4 receptor antagonists, but also have improved affinity for the said receptor compared to the corresponding quinazolines and isomeric pyrido[4,3-pyrimidine connections.

Moreover, the present inventors have unexpectedly discovered that the compounds of formula (I) can also be active as histamine H1 receptor antagonists and can therefore inhibit both histamine receptors. This dual inhibition provides improved effect in diseases and disorders in which both receptors are involved, such as type I allergic diseases.

Therefore, according to a first aspect, the present invention relates to a compound of formula (I'):

Where:

R ¹ is selected from hydrogen, halogen, optionally substituted C1-6alkyl, OR ⁴ , SR ⁴ , NR ⁴ R ⁵ , where R ⁴ and R ⁵ are independently selected from H and optionally substituted C1-6alkyl;

X is selected from -O- and -NR ⁶ -, where R ⁶ is selected from H;

R ² selected from:

C _1-6 alkyl optionally substituted:

optionally substituted C _3-7 cycloalkyl, optionally substituted C _6-10 aryl, optionally substituted 5-10 membered heterocyclyl,

- 1 044615 optionally substituted 5-10 membered heteroaryl and

SOR ¹³ , where R ¹³ is selected from optionally substituted C _1-6 alkyl, optionally substituted

C _6-10 aryl, optionally substituted (C _6-10 )aryl(C _1-6 )alkyl, optionally substituted 5-10 membered heterocyclyl and optionally substituted 5-10 membered heteroaryl;

SO2R ¹⁴ where R ¹⁴ is selected from optionally substituted C _1-6 alkyl, optionally substituted C _6-10 aryl, optionally substituted (C _6-10 )aryl(C _1-6 )alkyl, optionally substituted 5-10 membered heterocyclyl and optionally substituted 510-membered heteroaryl;

SO2NR15R ¹⁶ , where R ¹⁵ and R ¹⁶ are independently selected from H, optionally substituted C _1-6 alkyl, optionally substituted C _3-7 cycloalkyl, optionally substituted C _6-10 aryl, optionally substituted (C _6-10 )aryl(C _{1 -6} )alkyl, optionally substituted 5-10 membered heterocyclyl and optionally substituted 5-10 membered heteroaryl; And

SO(=NH)NHR ¹⁷ , where R ¹⁷ is selected from H, optionally substituted C _1-6 alkyl, optionally substituted C _3-7 cycloalkyl, optionally substituted C _6-10 aryl, optionally substituted (C _6-10 )αryl(C _1-6 )alkyl, optionally substituted 5-10 membered heterocyclyl and optionally substituted 5-10 membered heteroaryl;

optionally substituted C _3-7 cycloalkyl;

optionally substituted C _6-10 aryl; and optionally substituted (C _6-10 )aryl(C _1-6 )alkyl; R ³ selected from:

optionally substituted 5-10 membered heterocyclyl and

NR ¹⁸ R ¹⁹ wherein R ¹⁸ is selected from H and C1-6alkyl, and ^R19 is selected from C1-6alkyl optionally substituted with optionally substituted 5-10 membered heterocyclyl or optionally substituted 5-10 membered heteroaryl;

with the proviso that the compound of formula (I) is not (4-fluorobenzyl)-(2-piperidin-1ylpyrido[3,4-b]pyrimidin-4-yl)amine; and [2-(3,4-dihydro-1H-isoquinolin-2-yl)pyrido[3,4b]pyrimidin-4-yl]pyridin-4-ylmethylamine.

Another aspect of the invention relates to a compound of formula (I)

(I) where:

R ¹ is selected from hydrogen, halogen, optionally substituted C1-6alkyl, OR ⁴ , SR ⁴ , NR ⁴ R ⁵ , where R ⁴ and R ⁵ are independently selected from H and optionally substituted C1-6αalkyl;

X is selected from -O- and -NR ⁶ -, where R ⁶ is selected from H;

R ² selected from:

C _1-6 alkyl optionally substituted:

C _1-6 alkyl, optionally substituted C _3-7 cycloalkyl, optionally substituted C _6-10 aryl, optionally substituted 5-10 membered heterocyclyl, optionally substituted 5-10 membered heteroaryl,

SOR ¹³ where R ¹³ is selected from optionally substituted C _1-6 alkyl, optionally substituted C _6-10 aryl, optionally substituted (C _6-10 )aryl(C _1-6 )alkyl, optionally substituted 5-10 membered heterocyclyl and optionally substituted 510-membered heteroaryl;

SO2R ¹⁴ where R ¹⁴ is selected from optionally substituted C _1-6 alkyl, optionally substituted C _6-10 aryl, optionally substituted (C _6-10 )aryl(C _1-6 )alkyl, optionally substituted 5-10 membered heterocyclyl and optionally substituted 5-10 membered heteroaryl;

SO2NR ¹⁵ R ¹⁶ where R ¹⁵ and R ¹⁶ are independently selected from H, optionally substituted C _1-6 alkyl, optionally substituted C ₃ .7 cycloalkyl, optionally substituted C _6-10 aryl, optionally substituted (C _6-10 )aryl( C _1-6 )alkyl, optionally substituted 5-10 membered heterocyclyl and optionally substituted 5-10 membered heteroaryl; And

SO(=NH)NHR ¹⁷ , where R ¹⁷ is selected from H, optionally substituted C _1-6 alkyl, optionally substituted C _3-7 cycloalkyl, optionally substituted C _6-10 aryl, optionally substituted (C _6-10 )αryl(C _1-6 )alkyl, optionally substituted 5-10 membered heterocyclyl and optionally substituted 5-10 membered heteroaryl;

optionally substituted C _3-7 cycloalkyl;

optionally substituted C _6-10 aryl; and optionally substituted (C _6-10 )aryl(C _1-6 )αalkyl; R ³ selected from:

- 2 044615 optionally substituted 5-10 membered heterocyclyl and

NR18R ¹⁹ where R ¹⁸ is selected from H and C1.6alkyl, and R ¹⁹ is selected from C1. ₆ alkyl, optionally substituted with optionally substituted 5-10 membered heterocyclyl or optionally substituted 5-10 membered heteroaryl;

with the proviso that the compound of formula (I) is not [2-(3,4-dihydro-III-isoquinolin-2-yl)pyrido[3,4-d]pyrimidin-4-yl]pyridin-4-ylmethylamine;

for use in the treatment and/or prevention of a histamine H4 receptor-mediated disorder or disease.

Another aspect of the invention are compounds of formula (I), as defined above, for use in the treatment and/or prevention of a disorder or disease susceptible to improvement by histamine H4 receptor antagonism.

Detailed Description of the Invention

In the context of the present invention, the following terms have the meanings described in detail below.

Term C ₁ . ₆ αlkyl refers to a straight or branched hydrocarbon chain radical consisting of carbon and hydrogen atoms, containing no unsaturation, having from 1 to 6, preferably from 1 to 3 (C ₁ . ₃ alkyl), more preferably 1 or 2 (C ₁ . ₂ alkyl), carbon atoms and which is attached to the rest of the molecule by a single bond, including, for example and without limitation, methyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl, n-pentyl and etc. Preferably alkyl refers to methyl or ethyl.

The term _{C3_7cycloalkyl} refers to a saturated or partially saturated mono- or bicyclic aliphatic group having from 3 to 7, preferably from 3 to 6 carbon atoms, which is linked to the rest of the molecule by a single bond, including, for example, and in a non-limiting sense, cyclopropyl, cyclohexyl, cyclopentyl, etc.

The term C ₆ - ₁₀ aryl refers to an aromatic group having from 6 to 10, preferably 6 or 10 carbon atoms, containing 1 or 2 aromatic rings, including, for example and without limitation, phenyl, naphthyl and the like. Preferably, aryl refers to phenyl.

5-10 membered heterocyclyl refers to a stable 5-10 membered ring radical, preferably a 5- or 6-membered ring, which consists of carbon atoms and 1 to 4 heteroatoms selected from the group consisting of nitrogen, oxygen and sulfur , and which may be partially or fully saturated. For purposes of the present invention, the heterocycle may be a monocyclyl or bicyclyl ring system. Examples of such heterocycles include, but are not limited to, pyrrolidine, piperidine, tetrahydropyridine, piperazine, morpholine, thiomorpholine, diazepane, tetrahydrofuran, tetrahydropyran, octahydropyrrolopyrazine.

5-10 membered heteroaryl refers to a stable 5-10 membered aromatic ring radical, preferably a 5- or 6-membered aromatic ring, which consists of carbon atoms and 1 to 4 heteroatoms selected from the group consisting of nitrogen, oxygen and sulfur. For purposes of the present invention, heteroaryl may be a monocyclyl or bicyclyl ring system. Examples of such heteroaryl include, but are not limited to, thiophene, furan, pyrrole, thiazole, oxazole, isothiazole, isooxazole, imidazole, pyrazole, triazole, oxadiazole, thiadiazole, tetrazole, tetrazole oxide, oxadiazolone, pyridine, pyrimidine, dihydroindolone, benzimidazole, benzothiazole, benzofuran, indole, purine, quinoline.

The term (C ₆ -C ₁₀ )aryl(C1-C ₆ )alkyl refers to an aryl group, as defined above, which is attached to the rest of the molecule through an alkyl group, as defined above. Preferably (C ₆ -C ₁₀ )aryl(C1-C ₆ )alkyl is (C ₆ )aryl(C1-C ₃ )alkyl such as benzyl.

The term C ₁ -C ₆ haloalkyl refers to an alkyl group, as defined above, in which at least one of the hydrogen atoms is replaced by a halogen atom, such as, for example, CF ₃ , CCl ₃ , CHF 2 , CH 2 F , CF 2 CF 3 .

The term halogen refers to bromine, chlorine, iodine or fluorine.

As is understood in this technical field, there may be a certain degree of substitution on previously defined radicals. Thus, substitution may occur in any of the groups of the present invention. References herein to substituted groups in groups of the present invention indicate that the specified radical may be substituted at one or more accessible positions by one or more substituents. Said substituents include, for example, and without limitation, halogen, optionally substituted with C ₁ . ₆ alkyl, C ₁ . ₆ haloalkyl, -N(R _a )(R _b ), -OR _c , -SR _d ; where R _a , R _b , K, R _d are independently selected from hydrogen, C ₁ . ₆ αlkyl, C ₁ . ₆ haloalkyl, C ₆ - ₁₀ aryl, (C ₆ . ₁₀ ) aryl (C ₁ . ₆ ) alkyl.

Compounds of formula (I).

In a first aspect, the invention relates to a compound of formula (I), wherein said compound of formula (I) is not (4-fluorobenzyl)-(2-piperidin-1-ylpyrido[3,4-d]pyrimidin-4-yl)amine; and [2(3,4-dihydro-1H-isoquinolin-2-yl)pyrido[3,4-d]pyrimidin-4-yl]pyridin-4-ylmethylamine. Such a compound is designated herein as a compound of formula (I').

- 3 044615

Specific and preferred embodiments of the compounds of formula (I) and (I') are described below.

In a specific embodiment, X is selected from -O- and -NR ⁶ -, where R ⁶ is selected from H.

In another embodiment, X is -NR ⁶ -, where R ⁶ is selected from H.

In another embodiment, X is selected from -O- and -NH-.

Preferably, X is -NH-.

In one embodiment of the invention, R ¹ is selected from hydrogen, halogen, optionally substituted C1.6αalkyl, OR ⁴ , SR ⁴ , NR ⁴ R ⁵ , where R ⁴ and R ⁵ are independently selected from H and optionally substituted C1. ₆ alkyl.

In one embodiment of the invention, R ¹ is selected from:

hydrogen, halogen,

C ₁ . ₆ alkyl, optionally substituted with halogen, C ₁ . ₆ αlkyl, C ₁ . ₆ haloalkyl, -N(R _a )(R _b ), -OR _c , -SRd; where R _a , R _b , R _c , Rd are independently selected from hydrogen, C ₁ . ₆ αlkyl, C ₁ . ₆ haloalkyl, C _6-10 aryl and (C6.1o)aryl(C1.6)alkyl,

- OR ⁴ , SR ⁴ , NR ⁴ R ⁵ , where R ⁴ and R ⁵ are independently selected from H and C ₁ . ₆ alkyl, optionally substituted with halogen, C ₁ . ₆ alkyl, C ₁ . ₆ haloalkyl, -N(R _a )(R _b ), -ORc, -SRd; where R _a , R _b , Rc Rd are independently selected from hydrogen, C ₁ . ₆ alkyl, C ₁ . ₆ haloalkyl, C ₆ _ ₁₀ aryl and (C ₆ . ₁₀ ) aryl (C ₁ . ₆ ) alkyl.

In another embodiment, R ¹ is selected from:

hydrogen, halogen,

C ₁ . ₆ alkyl, optionally substituted with halogen, C ₁ . ₆ alkyl, -N(R _a )(R _b ), -OR _c , -SR _d ; where R _a , R _b , R _c , Rd are independently selected from hydrogen and C ₁ . ₆ alkula, -OR ⁴ , SR ⁴ , where R ⁴ and R ⁵ are independently selected from H and Cl. ₆ alkyl, optionally substituted with halogen, C ₁ . ₆ alkyl, -N(R _a )(R _b ), -ORc -SRd; where R _a , R _b , R _c , Rd are independently selected from hydrogen and C ₁ . ₆ alkyl.

In another embodiment, R ¹ is selected from:

hydrogen, halogen,

C ₁ . ₆ alkyl, optionally substituted with halogen, C ₁ . ₆ alkyl, -NH2, -OH, and

SC ₁ . ₆ αlkylα, NHR ⁵ where R ⁵ represents C ₁ . ₆ alkyl, optionally substituted with OH.

Preferably, R ¹ is selected from halogen and C ₁ . ₆ alkyl. More preferably, R ¹ is halogen, even more preferably Cl.

In a specific embodiment, when R2 is optionally substituted _{C3_7cycloalkyl} , optionally _{substituted C6_10} aryl, _or optionally substituted _{( C6.10} )aryl( _C1.6 )alkyl, said _{C3_7cycloalkyl} , _C6-10 aryl and (C ₆ . ₁₀ ) aryl (C ₁ . ₆ ) alkyl are optionally substituted with halogen, C ₁ . ₆ alkyl, C ₁ . ₆ haloalkyl, C _6-10 aryl, (C ₆ . ₁₀ ) aryl (C ₁ . ₆ ) alkyl.

In a particular embodiment of the invention, R ² is optionally substituted C ₁ . ₆ alkyl, preferably optionally substituted with C ₁ . ₃ alkyl, even more preferably it is optionally substituted C ₁ . ₂ alkyl

In one embodiment, R ² represents C ₁ . ₆ alkyl, preferably C ₁ . ₃ αlkyl, optionally substituted:

With _{3_7cycloalkyl} , optionally substituted with halogen, C ₁ . ₆ alkyl, C _6-10 aryl or (C ₆ . ₁₀ ) aryl (C ₁ . ₆ ) alkyl,

With _6-10 aryl, optionally substituted with halogen, C ₁ . ₆ alkyl, C _6-10 aryl or (C ₆ . ₁₀ ) aryl (C ₁ . ₆ ) alkyl,

5-10 membered heterocyclyl, optionally substituted with halogen, C ₁ . ₆ alkyl, C _6-10 aryl or (C ₆ . ₁₀ ) aryl (C ₁ . ₆ ) alkyl,

5-10 membered heteroaryl, optionally substituted with halogen, C ₁ . ₆ alkyl, C ₃ _7 cycloalkyl, C _6-10 aryl, (C ₆ . ₁₀ ) aryl (C ₁ . ₆ ) alkyl, 5-10 membered heterocyclyl, 5-10 membered heteroaryl, -N(R _a )(R _b ), -OR _c , -SR _d ; where R _a , R _b , Rc R _d are independently selected from hydrogen, C ₁ . ₆ alkyl, C ₁ . ₆ haloalkyl, C _6-10 aryl, (C ₆ . ₁₀ ) aryl (C ₁ . ₆ ) alkyl;

SOR ¹³ , where R ¹³ is selected from C ₁ . ₆ αlkyl, C ₆ - ₁₀ aryl, (C ₆ . ₁₀ )aryl(C ₁ . ₆ )alkyl, 5-10 membered heterocyclyl and 5-10 membered heteroaryl, optionally substituted with C ₁ . ₆ αlkyl, C ₆ _ ₁₀ aryl, (C ₆ . ₁₀ )aryl(C ₁ . ₆ ) alkyl, halogen, -N(R _a )(R _b ), -ORc -SR _d , where R _a , R _b , Rc R _d is independently selected from hydrogen, C ₁₆ alkyl, C ₁ . ₆ haloalkyl, C _6-10 aryl, (C ₆ . ₁₀ )aryl (C ₁ . ₆ ) alkyl, 5-10 membered heterocyclyl and 5-10 membered heteroaryl;

SO2R ¹⁴ , where R ¹⁴ is selected from C ₁ . ₆ αlkyl, C ₆ _ ₁₀ aryl, (C ₆ . ₁₀ )αryl(C ₁ . ₆ )αlkyl, 5-10 membered heterocyclyl and 5-10 membered heteroaryl, optionally substituted with C ₁ . ₆ alkyl, C ₆ _ ₁₀ aryl, (C ₆ . ₁₀ )aryl(C ₁ . ₆ ) alkyl, halogen, -N(R _a )(R _b ), -OR _c , -SRdi, where R _a , R _b , Rc R _d are independently selected from hydrogen, C ₁ . ₆ alkyl, C ₁ . ₆ haloalkyl, C _6-10 aryl, (C ₆ . ₁₀ ) aryl (C ₁ . ₆ ) alkyl;

SO ₂ NR ¹⁵ R ¹⁶ , where R ¹⁵ and R ¹⁶ are independently selected from H and C ₁ . ₆ alkyl, C _6-10 aryl, (C ₆ . ₁₀ )aryl(C ₁ . ₆ )alkyl, 5-10 membered heterocyclyl and 5-10 membered heteroaryl, optionally substituted with C ₁ . ₆ alkyl, C ₁ . ₆ haloalkyl, C ₆ _ ₁₀ aryl, (C ₆ . ₁₀ )aryl(C ₁ . ₆ )alkyl, 5-10 membered heterocyclyl, 5-10 membered heteroaryl halogen, -N(Ra)(Rb), -ORc , -SRd, where Ra, Rb, Rc, Rd are independently selected from hydrogen, C ₁ . ₆ αlkyl, C ₁ . ₆ haloalkyl, C ₆ _ ₁₀ aryl, (C ₆ . ₁₀ ) aryl (C ₁ . ₆ ) alkyl; And

SO(=NH)NHR ¹⁷ , where R ¹⁷ is selected from H and C ₁ . ₆ αlkyl, C ₆ _ ₁₀ aryl, (C ₆ . ₁₀ )αryl(C ₁ . ₆ )αlkyl, 5-10 membered heterocyclyl and 5-10 membered heteroaryl, optionally substituted with C _1-6 alkyl, With _1-6 haloalkyl,

With _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, 5-10 membered heterocyclyl, 5-10 membered heteroaryl,

-N(R _a )(Rb), -ORc, -SRd, where Ra,

R _b , R _c , Rd are independently selected from hydrogen, C _1-6 alkyl, C _1-6 haloalkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, 5-10- membered heterocyclyl and 5-10 membered heteroaryl.

In another embodiment, R ² is C _1-3 alkyl, optionally substituted:

5- or 6-membered heteroaryl, optionally substituted with halogen, C _1-6 alkyl, C _3-7 cycloalkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, 5-10 membered heterocyclyl, 5-10-membered heteroaryl, -N(R _a )(R _b ), -ORc, -SR _d ; where R _a , R _b , R _c , Rd are independently selected from hydrogen, C _1-6 alkyl, C _1-6 haloalkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl;

SOR ¹³ , where R ¹³ is selected from C _1-6 alkyl, _C6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, 5-10 membered heterocyclyl and 510 membered heteroaryl, optionally substituted with C _{1 -6} alkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, halogen, -N(R _a )(R _b ), -ORc, -SRd, where R _a , R _b , Rc Rd are independently selected from hydrogen, C _1-6 alkyl, C _1-6 haloalkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, 5-10 membered heterocyclyl and 5- 10-membered heteroaryl;

SO2R ¹⁴ where R ¹⁴ is selected from C _1-6 alkyl, _C6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, 5-10 membered heterocyclyl and 5-10 membered heteroaryl, optionally substituted C _1-6 alkyl, C _6-10 aryl, (C ₆ _ ₁₀ )aryl(C _1-6 ) alkyl, halogen, -N(R _a )(R _b ), -OR _c , -SRd, where R _a , R _b , R _c , Rd are independently selected from hydrogen, C _1-6 alkyl, C _1-6 haloalkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, 5-10- membered heterocyclyl and 5-10 membered heteroaryl; And

SO ₂ NR ¹⁵ R ¹⁶ , where R ¹⁵ and R ¹⁶ are independently selected from H and C _1-6 alkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, 5-10 membered heterocyclyl and 5-10 membered heteroaryl, optionally substituted with C _1-6 alkyl, C _1-6 haloalkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, 5-10 membered heterocyclyl , 5-10-membered heteroaryl halogen, -N(R _a )(R _b ), -OR _c , -SR _d , where R _a , R _b , R _c , R _d are independently selected from hydrogen, C _1-6 alkyl , C _1-6 haloalkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, 5-10 membered heterocyclyl and 5-10 membered heteroaryl.

In a specific embodiment of the invention, XR ² represents a group of formula (II) or (V):

-NH-(CH ₂ )nZ -NH-(CH ₂ )n-SO ₂ NR ¹⁵ R ¹⁶ (II) (V) where:

n selected from 1, 2 and 3;

Z is selected from 5- or 6-membered heterocyclyl and 5- or 6-membered heteroaryl, optionally substituted with halogen or C _1-6 alkyl;

R ¹³ is selected from C _1-6 alkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, 5-10 membered heterocyclyl and 5-10 membered heteroaryl, optionally substituted with C _1-6 alkyl , With _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, halogen, -N(R _a )(R _b ), -OR _c , -SRd, where R _a , R _b , Rc Rd is independently selected from hydrogen, C _1-6 alkyl, C _1-6 haloalkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl;

R ¹⁴ is selected from C _1-6 alkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, 5-10 membered heterocyclyl and 5-10 membered heteroaryl, optionally substituted with C _1-6 alkyl , With _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, halogen, -N(R _a )(R _b ), -OR _c , -SRd, where R _a , R _b , Rc Rd is independently selected from hydrogen, C _1-6 alkyl, C _1-6 haloalkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl; And

R ¹⁵ and R ¹⁶ are independently selected from H and C _1-6 alkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, 5-10 membered heterocyclyl and 5-10 membered heteroaryl , optionally substituted with C _1-6 alkyl, C _1-6 haloalkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, 5-10 membered heterocyclyl, 5-10 membered heteroaryl halogen , -N(R _a )(R _b ), -ORc, -SRd, where R _a , R _b , R _c , R _d are independently selected from hydrogen, C _1-6 alkyl, C _1-6 haloalkyl, C _{6- 10} aryl, (C _6-10 )aryl(C _1-6 )alkyl.

In a preferred embodiment, n is 1 or 2.

In another embodiment, Z is a 5- or 6-membered heteroaryl, preferably a 5-membered heteroaryl, optionally substituted with halogen or C _1-6 alkyl.

In a preferred embodiment, Z is selected from thiophene, furan, oxazole and thiazole, preferably thiophene optionally substituted with halogen or C _1-6 alkyl.

In another embodiment, R ¹³ is selected from C _1-6 alkyl, C _6-10 aryl and (C _6-10 )aryl(C _1-6 )alkyl, optionally substituted with C _1-6 alkyl, C _6-10 aryl, halogen, -N(R _a )(R _b ), or -OR _c , where R _a , R _b and R _c are independently selected from hydrogen and C _1-6 alkyl. Preferably it is selected from C _1-3 alkyl, phenyl and phenyl(C _1-3 )alkyl, optionally substituted with C _1-3 alkyl, phenyl, -N(R _a )(R _b ), or -ORc, where R _a R _b and R _c are independently selected from hydrogen and C _1-3 alkyl.

In another embodiment, R ¹⁴ is selected from C _1-6 alkyl, C _6-10 aryl and (C _6-10 )aryl(C _1-6 )alkyl, optionally substituted with C _1-6 alkyl, C _6-10 aryl, halogen, -N(R _a )(Rb), or -OR _c , where R _a , Rb and R _c are independently selected from hydrogen and C _1-6 alkyl. Preferably it is selected from C _1-3 alkyl, phenyl and phenyl(C _1-3 )alkyl, optionally substituted with C _1-3 alkyl, phenyl, -N(R _a )(Rb), or -ORc, where R _a , Rb and R _c

- 5 044615 are independently selected from hydrogen and C _1-3 alkyl.

In a preferred embodiment, R ¹⁵ is selected from H and C _1-6 alkyl, optionally substituted with halogen, -N(R _a )(Rb), -ORc, -SRdi, where Ra, Rb, Rc, Rd are independently selected from hydrogen,

_C1-6 alkyl, _C1-6 haloalkyl, _C6-10 aryl and ( _C6-10 )aryl( _C1-6 )alkyl.

More preferably, R ¹⁵ is selected from H and C _1-3 alkyl, optionally substituted by -N(R _a )(Rb) or OR _c , where Ra, Rb and R _c are independently selected from hydrogen and C _1-6 alkyl.

In another preferred embodiment, R ¹⁶ is selected from C _1-6 alkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )αalkyl and 5-10 membered heteroaryl, optionally substituted with C _1-6 alkyl, C _1-6 haloalkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, 5-10 membered heteroaryl, halogen, -N(R _a )(Rb), -OR _c or -SRd, where Ra, Rb, R _c and Rd are independently selected from hydrogen, C _1-6 alkyl and C _1-6 haloalkyl.

In another embodiment, R ¹⁶ is selected from C _1-3 alkyl, phenyl, phenyl(C _1-3 )alkyl and 5- or 6-membered heteroaryl, optionally substituted with C _1-3 alkyl, C _1-3 haloalkyl, phenyl, phenyl( C _1-3 )alkyl, 5- or 6-membered heteroaryl, halogen, -N(R _a )(Rb), -ORc or -SRd, where Ra, Rb, R _c and Rd are independently selected from hydrogen, C _{1- 3} alkyl and C _1-3 haloalkyl.

In one embodiment, R ² is selected from:

- 6 044615

In one embodiment of the invention, R ³ is selected from:

an optionally substituted 5-10 membered heterocyclyl, wherein the 5-10 membered heterocyclyl is not morpholine or tetrahydroisoquinoline; And

NR7R8', wherein R ⁷ is selected from H and C1-6alkyl, and ^R8 is selected from C1-6alkyl, optionally substituted with optionally substituted 5-10 membered heterocyclyl or optionally substituted 5-10 membered heteroaryl.

In a specific embodiment, R ³ is selected from:

5-10 membered heterocyclyl, optionally substituted with halogen, C _1-6 alkyl, C _1-6 haloalkyl, -N(R _a )(Rb), -ORc, -SRd, -C(O)R _e , -C( O)OR _f , -C(O)N(Rg)(R _h ) and -OC(O)Ri; where Ra, Rb, Rc, Rd, Re, R _f , Rg, R _h and Ri are independently selected from hydrogen, C _1-6 alkyl, C _1-6 haloalkyl, C _6-10 aryl and (C _6-10 )aryl (C _1-6 )alkyl. Preferably, a 5-10 membered heterocyclyl, optionally substituted with C _1-6 alkyl or -N(R _a )(Rb); where Ra and Rb are independently selected from hydrogen and C _1-6 alkyl; And

NR7R ⁸ wherein R ⁷ is selected from H and C1-6 alkyl, and R ⁸ is selected from C1-6 alkyl, optionally substituted with 5-10 membered heterocyclyl, optionally substituted with C _1-6 alkyl. Preferably, R ⁸ is selected from C _1-6 alkyl, optionally substituted with 5-10 membered heterocyclyl or 5-10 membered heteroaryl, optionally substituted with C _1-6 alkyl.

In one embodiment of the invention, R ³ is selected from:

an optionally substituted N-containing 5-10 membered heterocyclyl, and

NR7R ⁸ wherein R ⁷ is selected from H and C1-6alkyl, and ^R8 is selected from C1-6alkyl, optionally substituted with optionally substituted 5-10 membered heterocyclyl or optionally substituted 5-10 membered heteroaryl.

In another embodiment of the invention, R ³ is selected from:

an optionally substituted N-containing 5-10 membered heterocyclyl, and

NR7R ⁸ wherein R ⁷ is selected from H and C1-6 alkyl, and R ⁸ is selected from C1-3 alkyl optionally substituted with optionally substituted 5-10 membered heteroaryl.

In a specific embodiment, R ³ is selected from:

N-containing 5-10 membered heterocyclyl, optionally substituted with halogen, C _1-6 alkyl, C1-6 haloalkyl, -N(Ra)(Rb), -ORc, -SRd, -C(O)Re, -C(O )ORf, -C(O)N(Rg)(Rh) and -OC(O)Ri; where Ra, Rb, Rc, _Rd , Re, Rf, Rg, _Rh and Ri are independently selected from hydrogen, _C1-6 alkyl, _C1-6 haloalkyl, _C6-10 aryl and ( _C6-10 )aryl (C _1-6 )alkyl. Preferably, an N-containing 5-10 membered heterocyclyl, optionally substituted with C _1-6 alkyl or -N(R _a )(R _b ); where R _a and Rb are independently selected from hydrogen and C _1-6 alkyl; And

NR7R ⁸ where R ⁷ is selected from H and C1-6 alkyl, and R ⁸ is selected from C1-3 alkyl, optionally substituted with 510 membered heteroaryl, optionally substituted with halogen, C _1-6 alkyl, C _1-6 haloalkyl, -N(Ra )(Rb), -ORc, -SRd, -C(O)Re, -C(O)ORf, -C(O)N(Rg)(Rh) and -OC(O)Ri; where Ra, Rb, Rc, Rd, Re, Rf, Rg, Rh and Ri are independently selected from hydrogen, C _1-6 alkyl, C _1-6 haloalkyl, C _6-10 aryl and (C _6-10 )aryl(C _1-6 )alkyl. Preferably, R ⁸ is selected from C _1-3 alkyl, optionally substituted with 5-10 membered heteroaryl, optionally substituted with C _1-6 alkyl.

In a particular embodiment, when R ³ is an optionally substituted 5-10 membered heterocyclyl, it is preferably an optionally substituted N-containing 5-10 membered heterocyclyl. More preferably, it is an optionally substituted 5-10 membered heterocyclyl containing one or two nitrogen atoms. More preferably, an optionally substituted 5-10 membered heterocyclyl, in which the heterocyclyl ring consists of carbon atoms and one or two nitrogen atoms, such as pyrrolidine, piperidine, tetrahydropyridine,

- 7 044615 piperazine, diazepane, octahydropyrrolopyrazine, azetidine, octahydropyridopyrazine, octahydropyrrolopyrrole, diaza-spirononane, diaza-spiroundecane.

In another embodiment, when R ³ is an optionally substituted N-containing 5-10 membered heterocyclyl, said heterocyclyl is selected from:

In one embodiment, the N-containing 5-10 membered heterocyclyl is optionally substituted with halogen, C _1-6 alkyl, C _1-6 haloalkyl, -N(R _a )(R _b ), -ORc, -SRd, -C( O)Re, -C(O)ORf, -C(O)N(Rg)(R _h ) and -OC(O)Ri; where Ra, R _b , Rc, Rd, Re, Rf, Rg, R _h and Ri are independently selected from hydrogen, C _1-6 alkyl, C _1-6 haloalkyl, C _6-10 aryl and (C _6-10 )aryl (C _1-6 )alkyl. Preferably it is optionally substituted with C _1-6 alkyl or -N(R _a )(R _b ); where Ra and Rb are independently selected from hydrogen and C _1-6 alkyl.

In one embodiment, when R ³ is an optionally substituted N-containing 5-10 membered heterocyclyl, it is selected from:

In a preferred embodiment, R ³ is an optionally substituted 6-membered heterocyclyl, preferably an optionally substituted N-containing 6-membered heterocyclyl, more preferably an optionally substituted N-containing 6-membered heterocyclyl containing one or two nitrogen atoms.

In another embodiment, R ³ is selected from optionally substituted piperazine and optionally substituted ocatidropyrrolo[1,2-a]pyrazine.

In one embodiment, R ³ is an optionally substituted piperazine. In another embodiment, it is piperazine, optionally substituted with C _1-6 alkyl, preferably Me. Even more preferably, R ³ is 4methylpiperazinyl.

In another embodiment, R ³ is selected from:

-N NH -N NMe - Ν ’ ’ and

Preferably it is

In a preferred embodiment, R ³ is an optionally substituted N-containing 5-10 membered heterocyclyl as defined above.

In another preferred embodiment

R ¹ is selected from halogen, optionally substituted C1-6alkyl, OR ⁴ , SR ⁴ , NR ⁴ R ⁵ , where R ⁴ and R ⁵ are independently selected from H and optionally substituted C1-6alkyl; And

R ³ is an optionally substituted N-containing 5-10 membered heterocyclyl as defined above.

In another preferred embodiment

R ¹ is selected from halogen, optionally substituted with C _1-6 alkyl, OR ⁴ , SR ⁴ , NR ⁴ R ⁵ ,

- 8 044615 where R ⁴ and R ⁵ are independently selected from H and optionally substituted C _1-6 alkyl; preferably,

R ¹ represents chloride;

R ³ is an optionally substituted N-containing 5-10 membered heterocyclyl as defined above; preferably an optionally substituted piperazine.

According to another embodiment, a compound of the invention is selected from the group consisting of:

- 9 044615

- 10 044615

- 11 044615

- 12 044615

- 13 044615

Use of compounds of formula (I).

The compounds of formula (I) have been found to be antagonists of the histamine H4 receptor and thus may be useful for the treatment and/or prevention of diseases or disorders mediated by this receptor; in particular, diseases or disorders that can be improved by antagonism of the histamine H4 receptor.

Accordingly, an aspect of the invention relates to a compound of formula (I') for use as a medicament.

In another aspect, the invention provides a compound of formula (I) as defined above, for use in the treatment and/or prevention of a histamine H4 receptor mediated disorder or disease, preferably a disease or disorder susceptible to relief by histamine H4 receptor antagonism.

In one aspect, the invention relates to a compound of formula (I) as defined above, for use in the treatment and/or prevention of inflammatory diseases, including inflammatory skin diseases, inflammatory diseases of the gastrointestinal tract and inflammatory diseases of the eyes; allergic diseases; dermatological diseases; autoimmune diseases; pruritic diseases, lymphatic disorders, immunodeficiency diseases, respiratory diseases, heart diseases, kidney diseases, pain disorders, overactive bladder conditions, vestibular disorders, joint diseases and degenerative macular diseases.

In a specific embodiment, the invention relates to a compound of formula (I) as defined above, for use in the treatment and/or prevention of allergies, asthma, dry eyes, conjunctivitis, uveitis, allergic rhinitis, rhinoconjuntivitis, chronic obstructive airway disease (COPD) , atopic dermatitis, psoriasis, pruritus, uremic pruritus, urticaria, rheumatoid arthritis, psoriatic arthritis, colitis, Crohn's disease and ulcerative colitis, myocardial ischemia, diabetic nephropathy, inflammatory pain, neuropathic pain, dizziness, tinnitus, atherosclerosis, multiple sclerosis , mastocytosis and inflammatory or systemic lupus erythematosus. Exemplary types of inflammation that can be treated with the histamine H4 receptor modulating agent of the invention include inflammation caused by any of a variety of conditions such as allergies, asthma, dry eye, chronic obstruction

- 14 044615 active pulmonary disease (COPD), atherosclerosis, rheumatoid arthritis, multiple sclerosis, inflammatory bowel disease (including colitis, Crohn's disease and ulcerative colitis), psoriasis, pruritis, pruritus, atopic dermatitis, urticaria (rash), inflammation of the eye ( such as post-operative inflammation of the eye), conjunctivitis (eg, allergic conjunctivitis or vernal keratoconjunctivitis), nasal polyps, allergic rhinitis, itchy nose, scleroderma, autoimmune thyroid diseases, immune-mediated (also known as type 1) diabetes mellitus, and lupus, which are characterized by excessive or prolonged inflammation at one stage or another of the disease. Other autoimmune diseases that lead to inflammation include myasthenia gravis, autoimmune neuropathies such as Guillain-Barré, autoimmune uveitis, autoimmune hemolytic anemia, pernicious anemia, autoimmune thrombocytopenia, temporal arteritis, antiphospholipid syndrome, vasculitis such as Wegener's granulomatosis, Behçet's disease , dermatitis herpetiformis, dermatitis herpetiformis, pemphigus vulgaris, vitiligo, primary biliary cirrhosis, autoimmune hepatitis, autoimmune oophoritis and orchitis, autoimmune adrenal disease, polymyositis, dermatomyositis, spondyloarthropathies such as ankylosing spondylitis, and Sjögren's syndrome.

In a preferred embodiment, the compounds of formula (I) are antagonists of both histamine H1 and H4 receptors. Combination H1 and H4 antagonists have been found to be more effective than monotherapy in treating diseases or disorders that involve both receptors. Therefore, such compounds having affinity for the histamine H1 receptor in addition to the H4 receptor may be able to modulate inflammatory diseases (dermatitis, itch and inflammation) with both the H4R and H1R components more effectively than with selective H1Rs or H1Rs alone. selective H4R ligands.

The term treat or treat as used herein means administering a compound or composition of the invention to alleviate or eliminate a disease or one or more symptoms associated with said disease by modulating the activity of the histamine H4 receptor. Treatment also includes alleviating or eliminating the physiological effects of the disease.

The term improvement in the context of the present invention is understood to mean any improvement in the condition of a patient undergoing treatment.

The term prophylaxis or prevention as used herein means the administration of a compound or composition of the invention to reduce the risk of acquiring or developing a disease or one or more symptoms associated with said disease.

The present invention is further explained below with the help of examples. This explanation should in no way be interpreted as limiting the scope of the invention as defined in the claims.

Examples

The compounds of formula (I) according to the present invention were prepared in accordance with the general production strategy described in detail below. The detailed preparation of some compounds is described below.

Reagents and solvents were used as received from the commercial supplier without further purification unless otherwise stated. Reactions were carried out in Schlenk flasks or closed microwave reactors, usually under argon.

Reactions under the influence of microwave radiation were carried out on Anton Paar Monowave 450 equipment.

The reaction temperature specified in the experimental methods corresponds to the external temperature of the reaction system, measured using calibrated temperature sensors (conventional heating), or the internal temperature of the reactor, measured using a fiber optic temperature sensor (microwave-assisted reaction).

Low-temperature reactions were carried out using a Huber immersion refrigerator mod. TC100E equipped with a Pt100 sensor (temperature resistance ±0.5 K). In this type of process, the specified reaction temperature corresponds to the internal reaction temperature measured using calibrated temperature sensors.

Reactions were monitored by analytical thin layer chromatography using commercial aluminum plates precoated (0.2 mm layer thickness) with silica gel 60 F254 (E. Merck) or by UHPLC-MS chromatography. UHPLC/PDA/MS analytical analyzes were performed using a Waters Acquity H-Class chromatograph with an UHPLC-PDA optical detector and a QDa™ or TQD™ MS detector in scanning mode.

Chromatographic analyzes were carried out under the following conditions.

Method A: Column Kinetex C18 100X3.0 mm 2.6 µm column. Mobile phase: ammonium bicarbonate 10 mM (solvent A) and methanol (solvent B). Gradient at 0.6 mL/min from 95% to 5% solvent A in 9.0 min, then 0.5 min in 5% solvent A and back to 95% solvent A in another 0.5 min. Total execution time 10 minutes. Thermostat temperature setting is 30°C. Sample temperature 18°C.

- 15 044615

Method B: Column Kinetex C18 100X3.0 mm 2.6 µm column. Mobile phase: formic acid 0.1% (solvent A) and methanol (solvent B). Gradient at 0.6 ml/min from 95% to 5% solvent A for

9.0 min, then 0.5 min in 5% solvent A and back to 95% solvent A in another 0.5 min. Total execution time 10 minutes. Thermostat temperature setting is 40°C. Sample temperature 18°C.

The chromatographic method used for each compound is shown in parentheses after the purity value throughout the text, designated UHPLC-(method name).

Purification of the product by flash chromatography was performed using E. Merck silica gel (230,400 mesh). Visualization was performed under UV light. Product purification by automated preparative flash chromatography was carried out on a Combiflash® Rf+ flash chromatography system from Teledyne Isco or alternatively on a Reveleris® PREP system from Buchi using SiliaSep™ or SiliaSep™ C18) (17%) 4 g, 12 g or 24 g purchased from Silicycle (UV detection at three different wavelengths λ1=254 nm, λ2=280 nm and λ3=220-230 nm. Yields shown are actual yields unless otherwise noted.

The proton magnetic resonance spectrum was recorded at a frequency of 300 MHz using BRUKER Avance 300 MHz instruments in deuterated solvents: chloroform, methanol or dimethyl sulfoxide. Chemical shifts are reported in ppm relative to the TMS peak at 0.00 ppm or relative to the corresponding residual solvent signal. The letters m, s, d, t, q, fifth and sept stand for multiplet, singlet, doublet, triplet, quartet, quintuplet and septuplet, respectively. Letters width indicate a wide signal. All melting points are corrected and recorded on a Buchi instrument

B-540 using BUCHI™ Melting Point Capillary, part number 017808.

Synthesis of compounds of formula (I).

The compounds of formula (I) of the present invention can be synthesized in a multi-step sequence using available synthetic methods. For example, they can be obtained using a method briefly described in General Schemes 1-4 shown below.

Synthesis of key intermediate F.

The preparation of intermediate F, common to all examples described in the present invention, is shown in Scheme 1.

Scheme 1. Synthetic route for the preparation of intermediate compound F. Reagents and conditions: (i) Boc ₂ O, t-BuOH, 50°C; (ii) BuLi, TMEDA, Et ₂ O, -78°C, CO ₂ (r), H ₂ O; (iii) 4-DMAP, EDCI, CH ₂ Cl ₂ , 22°C, MeOH; (iv) conc. HCl, MeOH, 65°C; (v) urea, 150°C, 12 h; (vi) POCf, DIPEA, 110°C, 12 h.

Synthesis of Examples 1-38 and 68-99: Preparation of compounds of formula (I) wherein R ² is Nmethylpiperazine, piperazine, N-methylpyrrolidin-3-amine, 2-(1-methylpyrrolidin-2-yl)ethan-1-amine , 1methyl-1,4-diazepane, N-methylpiperidin-4-amine, piperidin-4-amine, pyrrolidine-3-amine, or octahydropyrrolo[1,2-a]pyrazine are depicted in Scheme 2, starting with the common intermediate F, shown in diagram 1.

CI XR

Scheme 2. Synthetic route for obtaining examples 1-38 and 68-99.

Reagents and conditions: (vii) RXH, DIPEA, EtOAc (0.14M), 22°C, t (h); R ³ R ² NH, μW, 120°С, t (min).

Synthesis of Examples 39-45: Preparation of compounds of formula (I) wherein R ² is piperidine, 1-methylpiperidine, 1-methyl-1,2,3,4-tetrahydropyridine or 1,2,3,6-tetrahydropyridine is shown in Scheme 3, starting from the common intermediate F shown in Scheme 1.

- 16 044615

Scheme 3. Synthetic route for obtaining examples 39-45.

Reagents and conditions: (viii) RNH2, DIPEA, EtOAc:DCM 1:1%v/v. (0.14M), 22°C, t (h); (ix) RBpin, Na ₂ CO ₃ (2M), THF (0.27M), μW, 100°C, t (h); (x) Pd(OH) ₂ 20%wt./wt. on coal, H ₂ (1 atm.), EtOAc:MeOH 2:1% v/v. (7 mM); (xi) conc. HCl, MeOH (0.1M).

Synthesis of examples 46-67. The preparation of compounds of formula (I) where the substitution R ³ is alkyl or -H is shown in Scheme 4, starting with Examples (3, 4, 6, 16, 17, 18, 24, 42 and 43) shown in Scheme 2 and 3.

Scheme 4. Synthetic route for obtaining examples 46-67.

Reagents and conditions: (xii) R ³ MX, PEPPSI™-IPr, LiCl, DME (4-6 mM), 70°C, 16 h; (xiii) Pd/C, H ₂ (1 atm), EtOAc:MeOH 2:1%v/v. (7 mM).

Step 1. Synthesis of intermediate A [CAS: 171178-45-3]: tert-butyl (6-chloropyridin-3yl)carbamate was prepared by adapting the method obtained from WO 2008/130021, WO 2006/024834 and Ohta et al., Bioorg. Med. Chem. 2008, 16, 7021-7032.

H

Η ₂ Νγ^ _Ν Boc ₂ O, t-BuOH (0.71 M) Boc' ^N >pN ^^731 50 °C, 361 h

In a 500 ml oven-dried round bottom flask, 5-amino-2-chloropyridine (20 g, 154 mmol, 1 eq.) was dissolved in tert-butanol (217 ml, 0.71 M), di-tert-butyl dicarbonate (38, 4 g, 172 mmol, 1.12 eq.) and the solution was stirred at 50°C. The reaction progress was monitored by TLC (heptane:EtOAc 30:60% v/v) until complete conversion of 5-amino-2-chloropyridine to intermediate A (36 h). The solvent was evaporated on a rotary evaporator and the residue was dissolved in ethyl acetate (500 ml). The organic phase was washed with water (3x150 ml), brine (1x150 ml), dried over anhydrous Na ₂ SO ₄ and volatiles were removed under reduced pressure to give a pink solid, which was purified by automated flash chromatography (elution with heptane: EtOAc: DCM 50:25:25%v/v), yielding tert-butyl (6chloropyridin-3-yl)carbamate as a white solid (35.29 g, 99.3% yield). Purity: 99.0% (UHPLC-A); mp: 127-129.1°C; ¹ H-NMR (CDCl3), δ (ppm): 8.245 (dd, 1H), 7.965 (d, 1H), 7.25 (dd, 1H), 6.66 br.s, NH), 1.52 ( s, 9H); LR-MS (ESI+): m/z= 229.1 Da [M+H] ⁺ , calc. for C10H ₁₃ ClN ₂ O ₂ : 228.7.

Step 2: Synthesis of Intermediate B [CAS: 171178-46-41: 5-((tert-butoxycarbonyl)amino)-2-chloroisonicotinate was prepared by adapting the method obtained from WO 2008/130021 and WO 2006/024834.

1. BuLi, TMEDA, Et ₂ O-78 °C Clx^^^COOH

I P ------------------------------------------------ -----------------------------------------I ||

N^>< _n -Boc 2. CO ₂ (d), -78 °C - 22 °C

H 3. H ₂ O N

In an oven-dried 500 mL three-neck round bottom flask, tert-butyl (6chloropyridin-3-yl)carbamate (Intermediate A) (5 g, 21.82 mmol, 1 equiv.) was dissolved in anhydrous diethyl ether (200 mL), to obtain a yellow solution. TMEDA 0.1M (11.7 mL, 76 mmol, 3.5 eq.) was added and the mixture was cooled to -78°C. A solution of 2.5 M n-butyllithium in hexane (30.5 ml, 76 mmol, 3.5 eq.) was added dropwise (the reaction mixture turned brownish-red). When the addition of the reagent was complete, the reaction mixture was allowed to warm to -10°C and stirred at this temperature for 3 hours.

The reaction mixture was then re-cooled to -78°C and a bag of carbon dioxide gas (1 gallon) was placed under Ar. The system was evacuated and flushed three times with carbon dioxide. The reaction mixture was stirred at -78°C under an atmosphere of carbon dioxide at atmospheric pressure for 4 hours. The reaction mixture was allowed to warm to 22°C and stirred for 18 hours. Water was added to the reaction mixture until the solids were completely dissolved (300 ml). The phases were separated and the aqueous phase was washed with diethyl ether (2x100 ml). The aqueous phase was then adjusted to pH 6.32 with 2.7 M HCl and extracted with diethyl ether (4x200 ml) and EtOAc (5x200 ml). The combined organic phases were dried over anhydrous Na ₂ SO ₄ and concentrated under reduced pressure to give 5-((tert-butoxycarbonyl)amino)-2-chloroisonicotinic acid as a pale yellow solid, (5.13 g, 87% yield). Purity: 99.1% (UHPLC-A); ^1H -NMR (DMSO- _d6 ), δ (ppm): 10.01 (s, 1H), 9.12 (s, 1H), 7.75 (s, 1H), 1.48 (s, 9H ); LR-MS (ESI+): m/z= 273.0 Da [M+H] ⁺ , calc. for С11Н1зСМО4: 272.7.

Step 3: Synthesis of Intermediate C [CAS: 305371-42-01: Methyl 5-((tert-butoxycarbonyl)amino)-2-chloroisonicotinate was prepared by adapting the method obtained from Haddleton et al., J. Am. Chem. Soc. 2012, 134, 7406-7413.

H H

Boc' ^N V^N 1.4-DMAP, EDCI, CH ₂ CI ₂ , 22 °C Boc^ApN HOOC^^CI ^{2 Me0H 22} ° ^c MeOOC^^CI

5-((tert-butoxycarbonyl)amino)-2-chloroisonicotinic acid (Intermediate B) (4.27 g, 15 mmol, 1 eq.) was added to an oven-dried 500 mL two-neck round bottom flask equipped with a magnetic stirrer. , and suspended in dichloromethane (187 ml, 0.08 M). 4-Dimethylaminopyridine (7.40 g, 60 mmol, 4 eq.) was added at 22° C. to obtain a homogeneous solution. N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (4.65 g, 30 mmol, 2 eq.) was added at this temperature and the crude mixture was stirred for 3 hours. Anhydrous MeOH (HPLC grade) was added to the solution (5 .5 ml, 135 mmol, 9 eq.) and the mixture was stirred for 1 hour at 22°C. The resulting mixture was refluxed using an aluminum oven for 72 hours. TLC (EtOAc:MeOH 90:10% v/v) showed complete conversion of intermediate B to intermediate C. The reaction mixture was allowed to reach 22°C and volatile the substances were removed under reduced pressure. Dichloromethane (150 ml) was added to the residue until completely dissolved and the mixture was transferred to a separatory funnel, washed with H ₂ O (1 x 70 ml), HCl 1 M (2 x 50 ml) and saturated NaCl solution (1 x 50 ml). The organic phase was dried with Na ₂ SO ₄ and filtered through a layer of Na ₂ SO ₄ on a filter plate. The solvent was removed under reduced pressure to give a brown solid, which was purified by automated flash chromatography (Heptane: EtOAc, product eluting with EtOAc 100% v/v) to give methyl 5-((tert-butoxycarbonyl)amino)-2- chlorisonicotinate as a pale yellow solid (4.04 g, 79% yield). Purity: 99.4% (UHPLC-A); mp: 90.0-95.8°C; 1H-NMR (CDCl ₃ ), δ (ppm): 9.68 br.s, NH), 9.49 (s, 1H), 7.73 (s, 1H), 7.20 (s, 1H), 3.91 (s, 3H), 1.47 (s, 9H); LR-MS (ESI+): m/z= 287.1 Yes [M+H] ⁺ , calc. for C12H15CMO4: 286.2

Step 4. Synthesis of intermediate D [CAS: 1073182-59-8]: n

Boc^V^N ^con Ch HCI________

MeOOC'^^CI MeOH (0.13M), 65 °C MeOOC^^CI

Methyl 5-((tert-butoxycarbonyl)amino)-2-chloroisonicotinate (intermediate C) (6.22 g, 21.68 mmol, 1 eq.) was dissolved in methanol (165 ml) and conc. hydrochloric acid (8.71 mL, 105 mmol, 4.85 eq.) was added to the solution. The resulting yellow solution was stirred and refluxed using an aluminum thermostat until complete conversion (22 hours). The reaction was monitored by TLC analysis (Heptane:EtOAc 30:60% v/v). MeOH was evaporated under reduced pressure. DCM was added until the residue was completely dissolved (160 ml), water (90 ml) was added. The pH of the aqueous phase (initial pH 0.3) was adjusted to 13.02 by adding 1.25 M sodium hydroxide solution and extracted with DCM (4x200 ml). The combined organic phases were dried over anhydrous Na ₂ SO ₄ , filtered and concentrated under reduced pressure to give methyl 5-amino-2chloroisonicotinate as a brown-yellow solid; (3.90 g, 95% yield). Purity: 98.4% (UHPLC-A); ¹ H-NMR (CDC^), δ (ppm): 8.0 (s, 1H), 7.6 (s, 1H), 3.91 (s, 3H);

LR-MS (ESI+): m/z= 187.0 Da [M+H] ⁺ , calc. for C7H7ClN ₂ O ₂ : 186.2.

- 18 044615

Step 5. Synthesis of Intermediate E [CAS: 2190512-63-9]:

O urea, 150 °C.

1 --------------------~ || I

MeOOC CI ^{12 4 N} ^ ^k N^O

Η

Urea (4.75 g, 79 mmol, 10 eq.) was melted in a 50 ml round bottom flask by heating at 150° C. using an aluminum thermostat. Intermediate D (1.48 g, 7.9 mmol, 1 eq) was added and the mixture was heated at 150°C overnight. The formation of brown oil was observed. The temperature was lowered to 100°C and water (30 ml) was added. The mixture was stirred at this temperature for 1 hour, allowing the unreacted urea to dissolve. The pH value of the aqueous phase (initial pH 7.63) was adjusted to 4.0 by adding 1 M HCl. The aqueous phase was extracted (3x70 ml) CHCl ₃ /iPrOH 4:1% v/v. The combined organic phases were dried over anhydrous Na ₂ SO ₄ , filtered and evaporated under reduced pressure to give a yellow solid, a mixture of intermediates D and E. The yellow solid was suspended in 100 ml DCM and stirred for 15 min. The suspension was filtered through a filter plate and washed with DCM (3x10 ml). The DCM containing phases were combined and the solvent was removed under reduced pressure to yield unreacted intermediate D. The filtered yellow solid was dried to yield 6-chloropyrido[3,4-d]pyrimidine-2,4(1H,3H)-dione as pale yellow solid (1.20 g, 72% yield). Purity: 93.9% (UHPLC-V); mp: 315.4-318.2°C; ¹ NMR (DMSO-d6), δ(ppm): 11.60 br.s, 2H, NH), 8.36 (s, 1H), 7.77 (s, 1H); LR-MS (ESI+): m/z= 198.1 Yes [M+H] ⁺ , calc. for C7H ₄ ClN ₃ O ₂ : 197.6.

Step 6: Synthesis of Intermediate F [CAS: 2143878-49-1]: 2,4,6-trichloropyrido[3,4d]pyrimidine was prepared by adapting the method obtained from Kool et al., J. Org. Chem. 2005, 70, 132-140; Rose et al., J. Chem. Soc., 1947, 775-783; Ohta et al., Bioorg. Med. Chem. 2008, 16, 7021-7032.

To 6-chloropyrido[3,4-d]pyrimidine-2,4(1H,3H)-dione (intermediate E).

(1.19 g, 6 mmol, 1 eq.) contained in a 100 ml two-neck round bottom flask, dried in an oven equipped with a Dimroth refrigerator, was added pre-distilled POCl ₃ (27 ml, 288 mmol, 48 eq.) and DIPEA (2.72 ml, 15.6 mmol, 2.6 eq.). The mixture was stirred at reflux (110°C) for 18 hours. Volatile substances were distilled off in a laboratory vacuum (200-300 mm Hg). The residue was dissolved in DCM (80 ml) and washed with water (2x30 ml) and saturated NaCl solution (1x30 ml). The organic phase was dried over anhydrous Na ₂ SO ₄ and filtered. The solvent was removed under reduced pressure to give 2,4,6-trichloropyrido[3,4d]pyrimidine as a light brown solid (1.22 g, 89% yield). Purity: 96.6% (UHPLC-V); mp: 107.7-110.3°C; ¹ H-NMR (CDCl ₃ ), δ (ppm): 9.30 (s, 1H), 8.07 (s, 1H); LR-MS (ESI+): m/z= 233.8 Da [M+H] ⁺ , calc. for C7H2Cl3N3: 232.9.

Stage 7. Synthesis of examples 1-38 and 68-99.

General synthesis method A:

C.I.

1. RXH, DIPEA, EtOAc (0.14M), 22 °C, t Μ

Τι Τ ι ----------------------------------------------- -----------------------

2. R ³ R ² NH, uW, 120 °C, 15-30 min

N Cl

Pr 1- 38

An oven-dried μW reactor was charged with 2,4,6-trichloropyrido[3,4-d]pyrimidine (intermediate F) (234 mg, 1 mmol, 1 eq.), sealed with a septum, and purged with Ar (3 cycles Ar/vacuum). EtOAc (7 mL, 0.14 M) and N,Ndiisopropylethylamine (0.51 mL, 2.9 mmol, 2.9 eq.) were then added and the mixture was homogenized by stirring for 5 min. The appropriate amine or alcohol (RXH) (1.05 mmol, 1.05 eq) was added. The resulting mixture was stirred at 22°C until complete conversion of intermediate F (2-20 hours). The appropriate amine (R ³ R ² NH) (1.5-10.3 mmol, 1.5-10.3 eq.) was added. The mixture was homogenized by stirring and reacted under microwave irradiation at 120°C for 15-30 min (energy power: 60 W). The progress of the reaction was confirmed by TLC (EtOAc:MeOH). The crude mixture was transferred to a round bottom flask by adding EtOAc and the volatiles were removed under reduced pressure. The residue was dissolved in EtOAc (70 ml) and transferred to a separatory funnel. The organic phase was washed with water (3x30 ml) and saturated NaCl solution (1x30 ml). The organic phase was dried over anhydrous Na ₂ SO ₄ and filtered through a layer of Na ₂ SO ₄ with a filter plate. The solvent was removed under reduced pressure to obtain a crude mixture, which was purified by automated flash chromatography (EtOAc:MeOH) to obtain the corresponding products (Examples 1-38 and 68-99).

- 19 044615

All reacting amines are commercially available with the exception of aminoalkylsulfonamides used in Examples 14-18, 26-28, 37-39, 41, 43, 45 and 71-90. The required aminoalkylsulfonamides were prepared using an adaptation of the protocol described in the literature: Smits et al., J. Med. Chem. 2010, 53, 2390-2400. It describes the explanation of the structure of all compounds used in this method, with the exception of: 2-amino-N-benzylethane-1-sulfonamide hydrochloride; white solid; Weight: 3.102 g; Yield: 35%; Purity: 84.0% (UHPLC-A); mp: 175.5-187.9°C; ¹ H-NMR (CDCl3:MeOD 4:1%v/v), δ (ppm):: 7.41-7.29 (m, 5H), 4.31 (s, 2H), 3.43 -3.31 (m, 4H); LR-MS (ESI+): m/z= 215.0 Da [M+H] ⁺ , calc. for C9H ₁₄ N ₂ O ₂ S (original free base): 214.1.

2-amino-N-(2-chlorophenyl)ethane-1-sulfonamide hydrochloride; pale orange crystals; Weight: 2.0 g; Yield: 83.0%; Purity: 98.2% (UHPLC-A); mp: 179.8-185.5°C; 1H-NMR (D2O), δ (ppm): 7.48-7.40 (m, 2H), 7.36-7.14 (m, 2H), 3.59 (t, 2H), 3.46 (t, 2H); LR-MS (ESI+): m/z= 235.0 Da [M+H] ⁺ , calc. for C ₈ H11ClN ₂ O ₂ S (original free base): 234.0.

2-amino-N-(o-tolyl)ethane-1-sulfonamide hydrochloride; yellow solid; Weight: 1.8 g; Yield: 77.4%; Purity: 85.2% (UHPLC-A); mp: 156.0-164.7°C; ¹ H-NMR (D2O), δ (ppm): 7.38-7.10 (m, 4H), 3.62 (t, 2H), 3.47 (t, 2H), 2.27 (s, 3H); LR-MS (ESI+): m/z= 215.2 Da [M+H] ⁺ , calc. for C9H _W N ₂ O ₂ S (original free base): 214.1.

2-amino-N-(2-methoxyphenyl)ethane-1-sulfonamide hydrochloride; pale brown solid; Weight: 2.0 g; Yield: 77.6%; Purity: 90.7% (UHPLC-A); mp: 152.7-160.0°C; ¹ H-NMR (D2O), δ (ppm): 7.37-7.22 (m, 2H), 7.05 (m, 1H), 6.95 (m, 1H), 3.82 (s, 3H), 3.60-3.40 (m, 4H); LR-MS (ESI+): m/z= 231.0 Da [M+H] ⁺ , calc. for C ₉ H ₁₄ N ₂ O ₃ S (original free base): 230.1.

2-amino-N-(2-aminophenyl)ethane-1-sulfonamide dihydrochloride; pale pink solid; Weight: 1.9 g; Yield: 63.0%; Purity: 94.1% (UHPLC-A); mp: 229.6-237.0°C; ¹ H-NMR (D2O), δ (ppm): 7.67-7.29 (m, 4H), 3.64 (t, 2H), 3.49 (t, 2H); LR-MS (ESI+): m/z= 216.1 Yes [M+H] ⁺ , calc. for C8H ₁₃ N ₃ O ₂ S (original free base): 215.1.

2-amino-N-(3-chlorophenyl)ethane-1-sulfonamide hydrochloride; pale brown solid; Weight: 1.8 g; Yield: 75.7%; Purity: 98.2% (UHPLC-A); mp: 122.7-137.8 °C; ¹ H-NMR (D2O), δ (ppm): 7.41-7.20 (m, 3H), 7.20-6.93 (m, 1H), 3.57 (t, 2H), 3. 39 (t, 2H); LR-MS (ESI+): m/z= 234.9 Da [M+H] ⁺ , calc. for C8H11ClN ₂ O ₂ S (original free base): 234.0.

2-amino-N-(3-(trifluoromethoxy)phenyl)ethane-1-sulfonamide hydrochloride; pale brown solid; Weight: 2.8 g; Yield: 87.4%; Purity: 93.6% (UHPLC-A); mp: 151.6-162.5°C; ¹ H-NMR (D2O), δ (ppm): 7.42 (t, 1H), 7.23-7.11 (m, 3H), 3.59 (t, 2H), 3.39 (t, 2H); LR-MS (ESI+): m/z= 284.9 Da [M+H] ⁺ , calc. for C9H11F3N2O3S (original free base): 284.0.

2-amino-N-(3-(trifluoromethyl)phenyl)ethane-1-sulfonamide hydrochloride; yellow solid; Weight: 0.439 g; Yield: 43.0%; Purity: 94.8% (UHPLC-A); mp: 201.5-203.5°C; ¹ H-NMR (D2O), δ (ppm): 7.56-7.36 (m, 4H), 3.55 (t, 2H), 3.37 (t, 2H); LR-MS (ESI+): m/z= 268.9 Da [M+H] ⁺ , calc. for C9H _n F3N ₂ O ₂ S (original free base): 268.1.

2-amino-N-(m-tolyl)ethane-1-sulfonamide hydrochloride; pale yellow solid; Weight: 1.6 g; Yield: 72.0%; Purity: 90.0% (UHPLC-A); mp: 141.6-148.0°C; 1H-NMR (D2O), δ (ppm): 7.24 (t, 1H), 7.03 (m, 3H), 3.53 (t, 2H), 3.37 (t, 2H), 2. 24 (s, 3H); LR-MS (ESI+): m/z= 215.0 Da [M+H] ⁺ , calc. for C ₉ H ₁₄ N ₂ O ₂ S (original free base): 214.1.

2-amino-N-(3-methoxyphenyl)ethane-1-sulfonamide hydrochloride; pale brown solid; Weight: 2.0 g; Yield: 84.5%; Purity: 94.4% (UHPLC-A); mp: 108.7-116.7°C; ¹ H-NMR (D2O), δ (ppm): 7.28 (t, 1H), 6.93-6.73 (m, 3H), 3.74 (s, 3H), 3.55 (t, 2H), 3.38 (t, 2H); LR-MS (ESI+): m/z= 231.0 Da [M+H] ⁺ , calc. for C9H ₁₄ N ₂ O ₃ S (original free base): 230.1.

2-amino-N-(3-(methylthio)phenyl)ethane-1-sulfonamide hydrochloride; pale yellow solid; Weight: 2.2 g; Yield: 53.8%; Purity: 95.6% (UHPLC-A); mp: 137.3-142.7°C; ¹ H-NMR (D2O), δ (ppm): 7.25 (m, 1H), 7.07 (m, 2H), 6.96 (m, 1H), 3.54 (t, 2H), 3 .38 (t, 2H,), 2.39 (s, 3H); LR-MS (ESI+): m/z= 246.9 Da [M+H] ⁺ , calc. for C9H ₁₄ N ₂ O ₂ S ₂ (original free base): 246.1.

2-amino-N-(4-chlorophenyl)ethane-1-sulfonamide hydrochloride; yellow solid; Weight: 2.1 g; Yield: 95.0%; Purity: 91.6% (UHPLC-A); mp: 198.2-212.2°C; ¹ H-NMR (D2O), δ (ppm): 7.42-7.17 (m, 2H), 7.16-6.93 (m, 2H), 3.52 (t, 2H), 3. 36 (t, 2H,); LR-MS (ESI+): m/z= 234.9 Da [M+H] ⁺ , calc. for C8H11ClN2O2S (original free base): 234.0.

2-amino-N-(4-(trifluoromethyl)phenyl)ethane-1-sulfonamide hydrochloride; orange-brown solid; Weight: 0.400 g; Yield: 47.1%; Purity: 97.0% (UHPLC-A); mp: 118.7-207.6°C; ¹ H-NMR (D2O), δ (ppm): 7.63 (d, 2H), 7.31 (d, 2H), 3.61 (t, 2H), 3.39 (t, 2H); LR-MS (ESI+): m/z= 268.9 Da [M+H] ⁺ , calc. for C9H11F3N2O2S (original free base): 268.1.

2-amino-N-(p-tolyl)ethane-1-sulfonamide hydrochloride; yellow-brown solid; Weight: 1.2 g; Yield: 89.3%; Purity: 89.0% (UHPLC-A); mp: 162.0-173.9°C; ¹ H-NMR (D2O), δ (ppm): 7.18 (d, 2H), 7.10 (d, 2H), 3.51 (t, 2H), 3.37 (t, 2H), 2 ,23 (s, 3H); LR-MS (ESI+): m/z= 215.0 Da [M+H] ⁺ , calc. for C9H ₁₄ N ₂ O ₂ S (original free base): 214.1.

2-amino-N-(4-(methylthio)phenyl)ethane-1-sulfonamide hydrochloride; gray solid; Weight:

- 20 044615

1.9 g; Yield: 67.7%; Purity: 95.8% (UHPLC-A); mp: 160.7-169.3°C; 1H-NMR (D2O), δ (ppm): 7.21 (d,

2H), 7.12 (d, 2H), 3.50 (t, 2H), 3.35 (t, 2H), 2.36 (s, 3H); LR-MS (ESI+): m/z= 246.9 Da [M+H] ⁺ , calc. For

C ₉ H ₁₄ N ₂ O ₂ S ₂ (original free base): 246.1.

2-amino-N-(pyridin-3-yl)ethane-1-sulfonamide hydrochloride; pale orange solid; Weight: 1.6 g; Yield: 66.3%; Purity: 89.8% (UHPLC-A); mp: 165.3-179.3°C; ¹ H-NMR (D ₂ O), δ (ppm): 8.72-8.62 (m, 1H), 8.51 (t, 1H), 8.39-8.24 (m, 1H), 7.97 (q, 1H), 3.92-3.65 (m, 2H), 3.62-3.31 (m, 2H); LR-MS (ESI+): m/z= 202.0 Da [M+H] ⁺ , calc. for C7H11N3O2S (original free base): 201.1.

2-amino-N-(6-chloropyridin-2-yl)ethane-1-sulfonamide hydrochloride; beige solid; Weight: 0.400 g; Yield: 20.3%; Purity: 94.3% (UHPLC-A); mp: 176.7-185.3°C; ¹ H-NMR (D2O), δ (ppm): 7.62 (t, 1H), 7.05 (dd, 1H), 6.81 (dd, 1H), 3.84 (t, 2H), 3 .40 (t, 2H); LR-MS (ESI+): m/z= 235.9 Da [M+H] ⁺ , calc. for C ₇ H ₁₀ ClN ₃ O ₂ S (original free base): 235.0.

2-amino-N-(pyridin-2-ylmethyl)ethane-1-sulfonamide hydrochloride; beige solid; Weight: 0.600 g; Yield: 24.0%; Purity: 97.0% (UHPLC-A); mp: 166.0-176.0°C; ¹ H-NMR (D2O), δ (ppm): 8.63 (dd, 1H), 8.51 (td, 1H), 8.00 (d, 1H), 7.91 (t, 1H), 4 .73 (s, 2H), 3.65 (t, 2H), 3.45 (t, 2H); LR-MS (ESI+): m/z= 216.0 Da [M+H] ⁺ , calc. for C8H ₁₃ N ₃ O ₂ S (original free base): 215.1.

2-amino-N-(pyrimidin-2-yl)ethane-1-sulfonamide hydrochloride; orange solid; Weight: 1.2 g; Yield: 52.0%; Purity: 91.5% (UHPLC-A); mp: 138.7-146.0°C; 1H-NMR (D2O), δ (ppm): 8.53 (d, 2H), 7.07 (t, 1H), 3.73 (t, 2H), 3.46 (t, 2H); LR-MS (ESI+): m/z= 203.0 Da [M+H] ⁺ , calc. for C ₆ H ₁₀ N ₄ O ₂ S (original free base): 202.1.

2-amino-N-(1,3-dimethyl-1H-pyrazol-5-yl)ethane-1-sulfonamide hydrochloride; pale yellow solid; Weight: 0.400 g; Yield: 14.5%; Purity: 90.6% (UHPLC-A); mp: 182.0-195.6°C; ¹ H-NMR (D2O), δ (ppm): 6.37-6.12 (m, 1H), 3.72 (s, 3H), 3.64 (t, 2H), 3.41 (t, 2H), 2.23 (s, 3H); LR-MS (ESI+): m/z= 219.0 Da [M+H] ⁺ , calc. for C7H ₁₄ N ₄ O ₂ S (original free base): 218.1.

Alternatively, the desired aminoalkyl sulfonamides used in Examples 91 and 92 were prepared as the corresponding protected derivatives (O-tert-butyldimethylsilyl) protected derivative for Example 91 and N-tert-butyloxycarbonyl protected derivative for Example 92) by an adaptation of the protocol described in Literature: Smits et al., J. Med. Chem. 2010, 53, 2390-2400. In these examples, an additional deprotection reaction step is required to obtain the target compound (see Examples 91 and 92).

2-amino-N-benzyl-N-(2-((tert-butyldimethylsilyl)oxy)ethyl)ethane-1-sulfonamide reacted in Example 91 was obtained as a white solid; Weight: 2.28 g; Yield: 75%; Purity: 98.0% (UHPLC-A); ¹ H-NMR (DMSO-d6), δ (ppm): 7.41-7.27 (m, 5H), 4.41 (s, 2H), 3.49 (t, 2H), 3.29- 3.10 (m, 4H), 2.93 (t, 2H), 0.81 (s, 9H), -0.04 (s, 6H); LR-MS (ESI+): m/z= 373.1 Da [M+H] ⁺ , calc. for C17H ₃₂ N ₂ O ₃ SSi: 372.2.

tert-butyl (2-((2-amino-N-benzylethyl)sulfonamido)ethyl)carbamate reacted in Example 92 was obtained as a pale yellow solid; Weight: 1.40 g; Yield: 67.0%; Purity: 93.8% (UHPLC-A); ¹ H-NMR (CDCl3), δ (ppm): 7.41-7.27 (m, 5H), 4.45 (s, 2H), 3.32 (t, 2H), 3.20 (t, 4H), 3.08 (t, 2H), 1.49 br.s, NH2), 1.43 (s, 9H); LR-MS (ESI+): m/z= 358.1 Yes [M+H] ⁺ , calc. for Ci6H27N3O4S: 357.2.

Moreover, in Examples 30 and 31 of the present invention, the reacting amine was used as a correspondingly protected derivative (Boc-protected). In these examples, an additional Boc deprotection reaction step was necessary to obtain the target compound.

Boc deprotection method: The corresponding Boc derivative (1 eq.) was dissolved in MeOH (0.1 M, HPLC grade). Added conc. hydrochloric acid (3 eq.) and the resulting yellow solution were stirred at reflux until complete conversion was achieved (320 h). The progress of the reaction was monitored by TLC (EtOAc:MeOH). The mixture was allowed to cool to 22°C and MeOH was removed under reduced pressure. The residue was dissolved in DCM, poured into water and transferred to a separatory funnel. The pH of the aqueous phase was adjusted to pH-14 by adding 1.25 M sodium hydroxide solution and extracted with DCM (3x40 ml). The combined organic phases were dried over anhydrous Na ₂ SO ₄ , filtered and concentrated under reduced pressure to give the corresponding unprotected compound.

The following compounds were prepared in accordance with the general method of synthesis A described above for examples 1-38 and 68-99.

Example 1: 6-chloro-4-ethoxy-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidine.

RXH: ethanol, 59 µl; t: 2 h; R3R2NH: 1-methylpiperazine, 0.54 ml, 5 mmol, 5 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 90:10% v/v) gave the title compound as a yellow solid; weight: 0.143 g; Yield: 40%; Purity: 85.5%

- 21 044615 (SVEZHK-V); ¹ H-NMR (CDCl ₃ ), δ (ppm): 8.70 (d, 1H), 7.70 (d, 1H), 4.55 (q, 2H), 3.96 (t, 4H), 2.52 (t, 4H),

2.37 (s, 3H), 1.50 (t, 3H); LR-MS (ESI+): m/z= 308.1 Yes [M+H] ⁺ , calc. for CuH^CMO: 307.1.

Example 2: 6-chloro-2-(4-methylpiperazin-1-yl)-4-phenoxypyrido[3,4-d]pyrimidine.

RXH: phenol, 89 µl; t: 12 h; R3R2NH: 1-methylpiperazine, 0.54 ml, 5 mmol, 5 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, eluting product with EtOAc 100% v/v) gave the title compound as a yellow solid; weight: 0.249 g; Yield: 67%; Purity: 95.6% (UHPLC-A); mp: 137.8-144.2°C; ¹ H-NMR (CDCl3), δ (ppm): 8.75 (d, 1H), 7.89 (d, 1H), 7.49-7.43 (m, 2H), 7.32 (t, 1H), 7.30-7.22 (m, 2H), 3.78 (brt, 4H), 2.39 (t, 4H), 2.30 (s, 3H); LR-MS (ESI+): m/z= 356.1 Yes [M+H] ⁺ , calc. for C18H ₁₈ ClN ₅ O: 355.1.

Example 3: 6-chloro-2-(4-methylpiperazin-1-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimidin-4amine.

RXH: 2-thiophenemethylamine, 0.11 ml; t: 5 h; R3R2NH: 1-methylpiperazine, 0.27 ml, 2.5 mmol, 2.5 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 96:4% v/v) gave the title compound as a yellow solid; weight: 0.279 g; Yield: 79%; Purity: 94.3% (UHPLC-A); mp: 150°C (cleavage); ¹ H-NMR (CDCl3), δ (ppm): 8.63 (s, 1H), 7.31 (s, 1H), 7.25 (dd, 1H), 7.05 (d, 1H), 6 .98 (dd, 1H), 6.01 (t, NH), 4.94 (d, 2H), 3.98 (t, 4H), 2.49 (t, 4H), 2.35 (s, 3H); LR-MS (ESI+): m/z= 375.0 Da [M+H] ⁺ , calc. for C17H1 ₉ ClN ₆ S: 374.1.

Example 4: 6-chloro-N-(furan-2-ylmethyl)-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-amine.

RXH: furan-2-ylmethanamine, 97.2 ml; t: 5 h; R3R2NH: 1-methylpiperazine, 0.27 ml, 2.5 mmol, 2.5 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 92:8% v/v) gave the title compound as a yellow solid; weight: 307 mg; Yield: 85%; Purity: 99.0% (UHPLC-V), mp: 158.1-170.2°C; ¹ H-NMR (CDCl ₃ ), δ (ppm): 8.63 (s, 1H), 7.41 (d, 1H), 7.32 (s, 1H), 6.37 (t, 1H), 6.33 (d, 1H), 5.87 (t, 1H), 4.77 (d, 2H), 3.96 (t, 4H), 2.49 (t, 4H), 2.36 (s , 3H); LR-MS (ESI+): m/z= 359.0 Yes [M+H]+, cal. for C^H^ClNgO: 358.1.

Example 5: 6-chloro-2-(4-methylpiperazin-1-yl)-N-(thiophen-3-ylmethyl)pyrido[3,4-d]pyrimidin-4amine.

RXH: 3-thiophenemethylamine, 0.11 ml; t: 3 h; R3R2NH: 1-methylpiperazine, 0.54 ml, 5 mmol, 5 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 89:11% v/v) gave the title compound as a yellow solid; weight: 0.335 g; Yield: 87%; Purity: 95.8% (UHPLC-A); ¹ H-NMR (CDCl3), δ (ppm): 8.62 (s, 1H), 7.34 (s, 1H), 7.33 (d, 1H), 7.26 (d, 1H), 7 .11 (d, 1H), 5.95 (t, NH), 4.78 (d, 2H), 3.96 (t, 4H), 2.51 (t, 4H), 2.37 (s, 3H); LR-MS (ESI+): m/z= 375.0 Da [M+H] ⁺ , calc. for C17H ₁₉ ClN ₆ S: 374.1.

Example 6: 6-chloro-2-(4-methylpiperazin-1-yl)-N-(2-(thiophen-2-yl)ethyl)pyrido[3,4-d]pyrimidin-4amine.

RXH: 2-(thiophen-2-yl)ethan-1-amine, 0.14 ml; t: 3 h; R3R2NH: 1-methylpiperazine, 0.17 ml, 1.5 mmol, 1.5 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution

- 22 044615

96:04%v/v) gave the title compound as a yellow solid; weight: 0.356 g;

Yield: 89%; Purity: 97.2% (UHPLC-V); mp: 160.4-175.1°C; ¹ H-NMR (CDCI3), δ (ppm): 8.62 (s, 1H), 7.27 (s, 1H), 7.20 (d, 1H), 6.98 (dd, 1H), 6 .87 (d, 1H), 5.83 (t, NH), 3.96 (t, 4H), 3.86 (dd, 2H), 3.23 (t, 2H), 2.51 (t,

4H), 2.36 (s, 3H); LR-MS (ESI+): m/z= 389.0 Da [M+H] ⁺ , calc. for C ₁₈ H ₂₁ C1N ₆ S: 388.1.

Example 7: 6-chloro-2-(4-methylpiperazin-1-yl)-N-(thiazol-2-ylmethyl)pyrido[3,4-d]pyrimidin-4amine.

RXH: 3-chloro-2-((chloro-15-azanyl)methyl)-2,3-dihydrothiazol-3-ium-2-ide, 192.9 mg; t: 4 h; R3R2NH: 1methylpiperazine, 1.16 ml, 10.3 mmol, 10.3 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 91:9% v/v) gave the title compound as a yellow solid; weight: 0.334 g; Yield: 88%; Purity: 99.0% (UHPLC-A); 1H-NMR (CD ₂ Cl ₂ :MeOD 2:1%v/v), δ (ppm): 8.53 (d, 1H), 7.78 (d, 1H), 7.71 (d, 1H), 7.38 (d, 1H), 4.23 (s, 2H), 3.90 (t, 4H), 2.48 (t, 4H), 2.33 (s, 3H); LR-MS (ESI+): m/z= 376.1 Da [M+H] ⁺ , calc. for Ci ₆ Hi8C1N7S: 375.1.

Example

8:

d]pyrimidin-4-amine.

N-((1H-imidazol-2-yl)methyl)-6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-

RXH: 2-(aminomethyl)imidazole dihydrochloride, 176.80 mg; t: 5 h; R ³ R ² NH: 1-methylpiperazine, 1.16 ml, 10.3 mmol, 10.3 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 78:22% v/v) gave the title compound as a yellow solid; weight: 0.278 g; Yield: 62%; Purity: 97.8% (UHPLC-A); ^1H -NMR (CD2Cl2:MeOD 2:1%v/v), δ (ppm): 8.49 (d, 1H), 7.87 (d, 1H), 6.94 (s, 2H) , 4.77 (s, 2H), 3.84 (t, 4H), 2.45 (t, 4H), 2.31 (s, 3H); LR-MS (ESI+): m/z= 359.1 Yes [M+H] ⁺ , calc. for C16H ₁₉ ClN ₈ : 358.1.

Example 9: 6-chloro-2-(4-methylpiperazin-1-yl)-N-phenylpyrido[3,4-d]pyrimidin-4-amine.

RXH: Aniline, 97 µl; t: 12 h; R3R2NH: 1-methylpiperazine, 0.54 ml, 5 mmol, 5 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 97:3% v/v) gave the title compound as a yellow solid; weight: 0.310 g; Yield: 85%; Purity: 97.2% (UHPLC-A); mp: 210.8-218.1°C; ¹ H-NMR (CDCl3), δ (ppm): 8.68 (s, 1H), 7.66 (d, 2H), 7.49 (s, 1H), 7.42 (t, 2H), 7 .30 br.s, NH), 7.19 (t, 1H), 3.92 (t, 4H), 2.48 (t, 4H), 2.34 (s, 3H); LR-MS (ESI+): m/z= 355.1 Yes [M+H] ⁺ , calc. for C18H ₁₉ ClN ₆ : 354.1.

Example 10: N-benzyl-6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-amine.

RXH: Benzylamine, 0.11 ml; t: 3 h; R ³ R ² NH: 1-methylpiperazine, 1.16 ml, 10.3 mmol, 10.3 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 96:4% v/v) gave the title compound as a yellow solid; weight: 0.285 g; Yield: 75%; Purity: 97.1% (UHPLC-A); ¹ H-NMR (CDCl3), δ (ppm): 8.62 (s, 1H), 7.38-7.30 (m, 5H), 7.36 (s, 1H), 5.95 (t, NH), 4.77 (d, 2H), 3.93 (t, 4H), 2.46 (t, 4H), 2.34 (s, 3H); LR-MS (ESI+): m/z= 369.1 Yes [M+H] ⁺ , calc. for C19H ₂₁ ClN ₆ : 368.2.

Example 11: 6-chloro-2-(4-methylpiperazin-1-yl)-N-(pyridin-2-ylmethyl)pyrido[3,4-d]pyrimidin-4amine.

- 23 044615

RXH: pyridin-2-ylmethanamine, 0.11 ml; t: 2 h; R ³ R ² NH: 1-methylpiperazine, 1.16 ml, 10.3 mmol, 10.3 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 80:20% v/v) gave the title compound as a yellow solid; weight: 0.229.52 g; Yield: 61%; Purity: 98.3% (UHPLC-V); mp: 182.3-193.5°C; ¹ H-NMR (CDCl ₃ ), δ (ppm): 8.62 (dm, 1H), 8.60 (s, 1H), 7.73 (td, 1H), 7.59 (t, NH), 7.47 (s, 1H), 7.36 (d, 1H), 7.27 (t, 1H), 4.82 (d, 2H), 3.94 (t, 4H), 2.48 (t , 4H), 2.35 (s, 3H); LR-MS (ESI+): m/z= 313.0 Da [M+H] ⁺ , calc. for C^oCW 369.2.

Example 12: 6-chloro-N-(4-fluorobenzyl)-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-amine.

RXH: 4-fluorophenyl)methanamine, 0.12 ml; t: 3 h; R3R2NH: 1-methylpiperazine, 1.16 ml, 10.3 mmol, 10.3 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 98:2% v/v) gave the title compound as a yellow solid; weight: 0.275 g; Yield: 70%; Purity: 98.4% (UHPLC-V); mp: 164°C (cleavage); ¹ H-NMR (CDCl3), δ (ppm): 8.63 (s, 1H), 7.33 (t, 1H), 7.32 (s, 1H), 7.04 (t, 1H), 5 .90 (t, NH), 4.74 (d, 2H), 3.92 (t, 4H), 2.48 (t, 4H), 2.34 (s, 3H); LR-MS (ESI+): m/z= 387.0 Da [M+H] ⁺ , calc. for C19H ₂₀ ClFN ₆ : 386.1.

Example 13: 6-chloro-N-(4-methylbenzyl)-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-amine.

RXH: n-tolylmethanamine, 0.13 ml; t: 2 h; R3R2NH: 1-methylpiperazine, 1.16 ml, 10.3 mmol, 10.3 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 95:5% v/v) gave the title compound as a yellow solid; weight: 0.355 g; Yield: 90%; Purity: 97.2% (UHPLC-V); mp: 181.2-198.0°C; ¹ H-NMR (CDCl ₃ ), δ (ppm): 8.62 (s, 1H), 7.29 (s, 1H), 7.26 (d, 1H), 7.18 (d, 1H), 5.81 (t, NH), 4.72 (d, 2H), 3.94 (t, 4H), 2.48 (t, 4H), 2.36 (s, 3H), 2.35 (s , 3H); LR-MS (ESI+): m/z=383.1 Yes [M+H] ⁺ , calc. for C20H23CW 382.2.

Example 14: 2-((6-chloro-2-(4-methylpiperazin-1 -yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N-methylethane-1 sulfonamide.

RXH: 2-amino-N-methylethane-1-sulfonamide hydrochloride, 185 mg; t: 12 h; R3R2NH: 1methylpiperazine, 0.54 ml, 5 mmol, 5 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 90:10% v/v) gave the title compound as a yellow solid; weight: 0.357 g; Yield: 87%; Purity: 97.4% (UHPLC-A); ¹ H-NMR (CDCl ₃ ), δ (ppm): 8.50 (s, 1H), 7.34 (s, 1H), 6.88 (t, NH), 4.01 (ds, 2H), 3.91 (t, 4H), 3.45 (t, 2H), 2.83 (s, 3H), 2.52 (t, 4H), 2.37 (s, 3H); LR-MS (ESI+): m/z= 400.2 Da [M+H] ⁺ , calc. for Ci5H22ClN7O2S: 399.1.

The compound from Example 14 (0.357 mg, 0.87 mmol, 1 eq.) was suspended in MeOH (9.7 mL, 0.09 M, HPLC grade) and HCl 1.25 M in MeOH (2.1 mL, 2.6 mmol, 3 eq.). The mixture was stirred at 22°C for 18 hours. Volatiles were removed under reduced pressure to quantitatively obtain 2-((6chloro-2-(4-methylpiperazin-1 -yl)pyrido[3,4-d]pyrimidin-4-yl )amino)-N-methylethane-1-sulfonamide hydrochloride as a yellow solid; Purity: 97.4% (UHPLC-A); mp: 232.9°C (decomposition); 1H NMR (D ₂ O), δ (ppm): 8.73 (s, 1H), 7.97 (s, 1H), 4.14 (t, 2H), 3.73 (brt, 4H), 3.60 (t, 4H), 3.31 (brt, 2H), 3.01 (s, 3H), 2.73 (s, 3H); LR-MS (ESI+): m/z= 400.2 Da [M+H] ⁺ , calc. for C ₁₅ H ₂₂ ClN ₇ O ₂ S (original free base): 399.1.

Example 15: N-benzyl-2-((6-chloro-2-(4-methylpiperazin-1 -yl)pyrido[3,4-d]pyrimidin-4-yl)amino)ethane-1 sulfonamide.

- 24 044615

RXH: 2-amino-N-benzylethane-1-sulfonamide hydrochloride, 234 mg; t: 12 h; R3R2NH: 1methylpiperazine, 0.54 ml, 5 mmol, 5 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 97:3% v/v) gave the title compound as a yellow solid; weight: 0.389 g; Yield: 80%; Purity: 97.7% (UHPLC-A); mp: 222.5-230.2°C; ¹ HNMR (MeOD), δ (ppm): 8.36 (s, 1H), 7.66 (s, 1H), 7.22-7.09 (m, 5H), 4.12 (s, 2H) , 3.86-3.79 (m, 6H), 3.22-3.20 (m, 2H), 2.39 (t, 4H), 2.23 (s, 3H); LR-MS (ESI+): m/z= 476.3 Da [M+H] ⁺ , calc. for C ₂₁ H ₂₆ ClN ₇ O ₂ S: 475.2.

The compound from Example 15 (0.389 mg, 0.8 mmol, 1 eq.) was suspended in MeOH (8.9 mL, 0.09 M, HPLC grade) and HCl 1.25 M in MeOH (1.9 mL, 2.4 mmol, 3 eq.). The mixture was stirred at 22°C for 17 hours. Volatiles were removed under reduced pressure to give N-benzyl-2-((6-chloro2-(4-methylniperazin-1-yl)nurido[3,4-d]pyrimudin- 4-yl)amino)ethane-1-sulfonamide hydrochloride in quantitative yield as a yellow solid; Purity: 96.7% (UHPLC-A); mp: 194.8204.6°C; ¹ H-NMR (D2O), δ (ppm): 8.38 (s, 1H), 7.47 (s, 1H), 7.16-7.10 (m, 5H), 4.19 (s, 2H), 3.90 (t, 2H), 3.683.62 (m, 4H), 3.41-3.37 (m, 4H), 3.20-3.15 (m, 2H), 2.97 (s, 3H); LR-MS (ESI+): m/z= 476.1 Yes [M+H] ⁺ , calc. for C21H ₂₆ ClN ₇ O ₂ S (original free base): 475.2.

Example 16: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)αmino)-N-phenylethan1-sulfonamide.

RXH: 2-amino-N-phenylethane-1-sulfonamide hydrochloride, 225.7 mg; t: 12 h; R ³ R ² NH: 1methylpiperazine, 0.54 ml, 5 mmol, 5 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 94:06% v/v) gave the title compound as a yellow solid; weight: 0.417 g; Yield: 90%; Purity: 99.5% (UHPLC-A); mp: 223.1-229.5°C; ¹ HNMR (MeOD), δ (ppm): 8.47 (s, 1H), 7.73 (s, 1H), 7.29-7.06 (m, 5H), 3.96 (t, 2H) , 3.83(t, 4H), 3.57 (t, 2H), 2.45 (t, 4H), 2.35 (s, 3H); LR-MS (ESI+): m/z= 462.1 Yes [M+H] ⁺ , calc. for C ₂₀ H ₂₄ ClN ₇ O ₂ S: 461.1.

The compound from Example 16 (0.417 mg, 0.9 mmol, 1 eq.) was suspended in MeOH (10 ml, 0.09 M, HPLC grade) and HCl 1.25 M in MeOH (2.2 ml, 2.7 mmol, 3 eq.). The mixture was stirred at 22°C for 15 hours. Volatiles were removed under reduced pressure to give 6-chloro-2-(piperazin1-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimidin- 4-amine hydrochloride in quantitative yield as a yellow solid; Purity: 99.5% (UHPLC-A); mp: 277.1°C (cleavage); ¹ H-NMR (MeOD:D2O 80:20%v/v), δ (ppm): 8.59 (s, 1H), 7.82 (s, 1H), 7.26-7.21 ( m, 2H), 7.11-7.06 (m, 3H), 4.05 (t, 4H), 3.70 (t, 4H), 3.69-3.11 br.s, 4H), 3.01 (s, 3H); LR-MS (ESI+): m/z= 462.1 Yes [M+H] ⁺ , calc. for C20H24ClN7O2S (original free base): 461.1.

Example 17: 2-((6-chloro-2-(4-methylpinerazin-1-yl)pyrido[3,4-d]nirimidin-4-yl)amino)-N-methyl-Nphenylethan-1-sulfonamide.

RXH: 2-amino-N-methyl-N-phenylethane-1-sulfonamide hydrochloride, 293 mg; t: 12 h; R ³ R ² NH: 1methylpiperazine, 0.54 ml, 5 mmol, 5 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 95:5% v/v) gave the title compound as a yellow solid; weight: 0.330 g; Yield: 69%; Purity: 99.2% (UHPLC-A); mp: 175.4-183.9°C; ¹ HNMR (CDCl3), δ (ppm): 8.59 (s, 1H), 7.37-7.26 (m, 5H), 7.36 (s, 1H), 6.48 (t, NH) , 4.06 (dd, 2H), 3.89 (t, 4H), 3.40 (t, 2H), 3.37 (s, 3H), 2.46 (t, 4H), 2.35 ( s, 3H); LR-MS (ESI+): m/z= 476.3 Da [M+H] ⁺ , calc. for C21H26ClN7O2S: 475.2.

Example 18: 6-chloro-2-(4-methylpiperazin-1 -yl)-N-(2-(morpholinosulfonyl)ethyl)pyrido[3,4d]pyrimidin-4-amine.

- 25 044615

RXH: 2-(morpholinosulfonyl)ethane-1-amine hydrochloride, 293 mg; t: 12 h; R ³ R ² NH: 1methylpiperazine, 0.54 ml, 5 mmol, 5 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 92:8% v/v) gave the title compound as a pale yellow solid; weight: 0.417 g; Yield: 90%; Purity: 98.2% (UHPLC-A); mp: 126.4136.8°C; 1H-NMR (CD ₂ Cl ₂ ), δ (ppm): 8.41 (s, 1H), 7.31 /s, 1H), 6.61 (t, NH), 4.00 (dd, 2H) , 3.81 (t, 4H), 3.65 (t, 4H), 3.23 (t, 2H), 3.19 (t, 4H), 2.37 (t, 4H), 2.22 ( s, 3H); LR-MS (ESI+): m/z= 456.2 Da [M+H] ⁺ , calc. for C18H26CIN7O3S: 455.2.

Example 19: 3 -(((6-chloro-2-(4-methylpiperazin-1 -yl)pyrido[3,4-d]pyrimidin-4-yl)amino)methyl)indolin-2-one.

RXH: 3-(aminomethyl)indolin-2-one hydrochloride, 210 mg; t: 12 h; R ³ R ² NH: 1-methylpiperazine, 0.32 ml, 3 mmol, 3 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 70:30% v/v) gave the title compound as a yellow solid; weight: 0.149 g; Yield: 30%; Purity: 84.8% (UHPLC-A); 1H-NMR (MeOD), δ (ppm): 8.50 (s, 1H), 7.88 (s, 1H), 7.26-7.23 (m, 2H), 7.02-6.91 (m, 2H), 4.14-3.88 (m, 3H), 3.97 (t, 4H), 2.60 (t, 4H), 2.41 (s, 3H); LR-MS (ESI+): m/z= 424.2 Da [M+H] ⁺ , calc. for C21H22CIN7O: 423.2.

Example 20: 6-chloro-N-isobutyl-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-amine.

RXH: isobutylamine, 0.1 ml; t: 3 h; R ³ R ² NH: 1-methylpiperazine, 0.54 ml, 5 mmol, 5 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, eluting product with EtOAc 100% v/v) gave the title compound as a yellow solid; weight: 0.248 g; Yield: 73%; Purity: 98.4% (UHPLC-A); mp: 160.4-163.1°C; ¹ H-NMR (CDCl3), δ (ppm): 8.61 (s, 1H), 7.37 (s, 1H), 5.89 (t, NH), 3.93 (t, 4H), 3 .41 (t, 2H), 2.49 (t, 4H), 2.35 (s, 3H), 2.03 (sept, 1H), 1.01 (d, 6H); LR-MS (ESI+): m/z= 335.2 Da [M+H] ⁺ , calc. for C16H ₂₃ ClN ₆ : 334.2.

Example 21: 6-chloro-N-cyclohexyl-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-amine.

RXH: cyclohexylamine, 0.12 ml; t: 2 h; R ² H: 1-methylpiperazine, 0.54 ml, 5 mmol, 5 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, eluting product with EtOAc 100% v/v) gave the title compound as a yellow solid; weight: 0.260 g; Yield: 72%; Purity: 99.7% (UHPLC-A); mp: 155.8-165.6°C; 1H-NMR ( _CDCl3 ), δ (ppm): 8.60 (s, 1H), 7.34 (s, 1H), 5.55 (d, NH), 4.14-4.03 (m, 1H), 3.92 (t, 4H), 2.49 (t, 4H), 2.35 (s, 3H), 2.17-2.07 (m, 2H), 1.87-1.76 (m, 2H), 1.741.65 (m, 1H), 1.52-1.23 (m, 5H); LR-MS (ESI+): m/z= 361.3 Da [M+H] ⁺ , calc. for C^ClNe: 360.2.

Example 22: N-butyl-6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-amine.

RXH: butylamine, 0.10 ml; t: 1 h; R3R2NH: 1-methylpiperazine, 0.54 ml, 5 mmol, 5 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, eluting product with EtOAc 100% v/v) gave the title compound as a yellow solid; weight: 0.154 g; Yield: 45%; Purity 26 044615: 97.9% (UHPLC-A); mp: 134.7-140.5°C; 1H-NMR ( _CDCl3 ), δ (ppm): 8.62 (s, 1H), 7.30 (s, 1H), 5.58 (t,

NH), 3.94 (t, 4H), 3.59 (dd, 2H), 2.49 (t, 4H), 2.35 (s, 3H), 1.74-1.64 (m, 2H ), 1.51-1.39 (m, 2H), 0.99 (t, 3H);

LR-MS (ESI+): m/z= 335.2 Da [M+H] ⁺ , calc. for C ₁₆ H ₂₃ ClN ₆ : 334.2.

Example 23: 6-chloro-N-(cyclohexylmethyl)-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-amine.

RXH: cyclohexanemethylamine, 0.13 ml; t: 2.5 h; R3R2NH: 1-methylpiperazine, 0.54 ml, 5 mmol, 5 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 91:9% v/v) gave the title compound as a yellow solid; weight: 0.240 g; Yield: 64%; Purity: 99.9% (UHPLC-A); mp: 92.8-103.5°C; ¹ H-NMR (CDCl3), δ (ppm): 8.60 (s, 1H), 7.37 (s, 1H), 5.89 (t, NH), 3.93 (t, 4H), 3 .43 (t, 2H), 2.49 (t, 4H), 2.35 (s, 3H) 1.82-1.62 (m, 6H), 1.1-0.96 (m, 5H) ; LR-MS (ESI+): m/z= 375.4 Da [M+H] ⁺ , calc. for C19H ₂₇ ClN ₆ : 374.2.

Example 24: 6-chloro-2-(piperazin-1-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimidin-4-amine.

RXH: 2-thiophenemethylamine, 0.11 ml; t: 5 h; R3R2NH: methylpiperazine hexahydrate, 980 mg, 5 mmol, 5 equiv.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 89:11% v/v) gave the title compound as a yellow solid; weight: 0.307 g; Yield: 82%; Purity: 96.3% (UHPLC-A); mp: 88.5-98.7°C; 1H-NMR (MeOD), δ (ppm): 8.43 (s, 1H), 7.78 (s, 1H), 7.24 (dd, 1H), 7.05 (d, 1H), 6. 94 (dd, 1H), 4.89 (d, 2H), 3.95 (t, 4H), 2.94 (t, 4H); LR-MS (ESI+): m/z= 361.0 Da [M+H] ⁺ , calc. for C ₁₆ H ₁₇ ClN ₆ S: 360.1.

The compound from Example 24 (0.307 mg, 0.82 mmol, 1 eq.) was suspended in MeOH (9.1 mL, 0.09 M, HPLC grade) and HCl 1.25 M in MeOH (2.0 mL, 2.5 mmol, 3 eq.). The mixture was stirred at 22°C for 16 hours. Volatiles were removed under reduced pressure to give 6-chloro-2(piperazin-1-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimidine -4-amine hydrochloride in quantitative yield as a yellow solid; Purity: 97.8% (UHPLC-A); mp: 211.47°C (cleavage); 1H-NMR (MeOD: D2O 80:20%v/v), δ (ppm): 8.82 (s, 1H), 8.15 (s, 1H), 7.38 (dd, 1H), 7.19 (d, 1H), 7.04 (dd, 1H), 5.06 (d, 2H), 4.29 (t, 4H), 3.47 (t, 4H); LR-MS (ESI+): m/z= 361.0 Da [M+H] ⁺ , calc. for C ₁₆ H ₁₇ ClN ₆ S (original free base): 360.1.

Example 25: 6-chloro-N-(furan-2-ylmethyl)-2-(piperazin-1-yl)pyrido[3,4-d]pyrimidin-4-amine.

RXH: furan-2-ylmethanamine, 97.2 µl; t: 5 h; R3R2NH: methylpiperazine hexahydrate, 980 mg, 5 mmol, 5 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 60:40% v/v) gave the title compound as a yellow solid; weight: 158 mg; Yield: 45%; Purity: 98.2% (UHPLC-A); ¹ H-NMR (MeOD), δ (ppm): 8.54 (d, 1H), 7.77 (d, 1H), 7.37 (dd, 1H), 6.34 (dd, 1H), 6 .28 (dd, 1H), 4.72 (s, 2H), 3.96 (t, 4H), 2.98 (t, 4H); LR-MS (ESI+): m/z= 345.0 Da [M+H] ⁺ , calc. for C ₁₆ H ₁₇ ClN ₆ O: 344.1.

Example 26: 2-((6-chloro-2-(piperazin-1-yl)nirido[3,4-d]pyrimidin-4-yl)amino)-N-phenylethan-1sulfonamide.

RXH: 2-amino-N-phenylethane-1-sulfonamide hydrochloride, 225.7 mg; t: 12 h; R3R2NH: methylpiperazine hexahydrate, 980 mg, 5 mmol, 5 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 60:40% v/v) gave the title compound as a yellow solid; weight: 0.3498 g; Yield: 71%; Purity: 90.9% (UHPLC-A); mp: 170.1-172.9°C; ¹ H-NMR (MeOD), δ (ppm): 8.44 (s, 1H), 7.72 (s, 1H), 7.30-7.06 (m, 5H), 3.99-3, 92 (m, 6H), 3.56 (t, 2H), 3.07 (t, 4H); LR-MS (ESI+): m/z= 448.1 Yes [M+H] ⁺ , calc. for C ₁₉ H ₂₂ ClN ₇ O ₂ S: 447.1.

- 27 044615

The compound from Example 26 (0.350 mg, 0.7 mmol, 1 eq.) was suspended in MeOH (7.8 mL, 0.09 M, HPLC grade) and HCl 1.25 M in MeOH (1.7 mL, 2.1 mmol, 3 eq.). The mixture was stirred at 22°C overnight. Volatiles were removed under reduced pressure to give 2-((6-chloro-2(piperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N-phenylethan-1-sulfonamide hydrochloride with quantitative yield as a yellow solid; Purity: 97.1% (UHPLC-V); mp: 142.2153.5°C; ¹ H-NMR (MeOD), δ (ppm): 8.47 (s, 1H), 7.73 (s, 1H), 7.29-7.05 (m, 5H), 3.96 (t, 2H), 3.82 (t, 4H), 3.57 (t, 2H), 2.87 (t, 4H); LR-MS (ESI+): m/z= 448.1 Yes [M+H] ⁺ , calc. for C ₁₉ H ₂₂ ClN ₇ O ₂ S (original free base): 447.1.

Example 27: 2-((6-chloro-2-(piperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N-methyl-Nphenylethan-1-sulfonamide.

RXH: 2-amino-N-methyl-N-phenylethane-1-sulfonamide hydrochloride, 293 mg; t: 12 h; R ³ R ² NH: methylpiperazine hexahydrate, 980 mg, 5 mmol, 5 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 60:40% v/v) gave the title compound as a yellow solid; weight: 0.399 g; Yield: 83%; Purity: 96.0% (UHPLC-A); mp: 86.5-92.0°C; ¹ HNMR (CDCl3), δ (ppm): 8.57 (s, 1H), 7.37-7.25 (m, 5H), 7.36 (s, 1H), 6.59 (t, NH) , 4.06 (dd, 2H), 3.84 (t, 4H), 3.42 (t, 2H), 3.37 (s, 3H), 2.92 (t, 4H), 2.59 ( s, 3H); LR-MS (ESI+): m/z= 462.2 Da [M+H] ⁺ , calc. for C2oH ₂ 4C1N70 ₂ S: 461.1.

Example 28: 6-chloro-N-(2-(morpholinosulfonyl)ethyl)-2-(piperazin-1-yl)pyrido[3,4-d]pyrimidin4-amine.

RXH: 2-(morpholinosulfonyl)ethane-1-amine hydrochloride, 293 mg; t: 12 h; R3R2NH: methylpiperazine hexahydrate, 980 mg, 5 mmol, 5 equiv.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 60:40% v/v) gave the title compound as a yellow solid; weight: 0.409 g; Yield: 87%; Purity: 94.1% (UHPLC-A); mp: 114.3-123.5°C; 1H-NMR (CD ₂ Cl ₂ ), δ (ppm): 8.43 (s, 1H), 7.55 (s, 1H), 3.93 (t, 2H), 3.79 (t, 4H) , 3.65 (t, 4H), 3.24 (t, 2H), 3.16 (t, 4H), 2.82 (t, 44; LR-MS (ESI+): m/z= 442.1 Yes [M+H] ⁺ , calculated for Sp^C^OzB: 441.1.

Example 29: 3-(((6-chloro-2-(piperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)methyl)indolin-2-one.

RXH: 3-(aminomethyl)indolin-2-one hydrochloride, 210 mg; t: 12 h; R ³ R ² NH: methylpiperazine hexahydrate, 980 mg, 5 mmol, 5 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 50:50% v/v) gave the title compound as a yellow solid; weight: 0.112 g; Yield: 20%; Purity: 73% (UHPLC-A); 1H-NMR (MeOD), δ (ppm): 8.50 (s, 1H), 7.88 (s, 1H), 7.25-7.19 (m, 2H), 7.01-6.90 (m, 2H), 4.16-3.84 (m, 3H), 3.94 (t, 4H), 2.94 (t, 2H), 2.76 (t, 2H); LR-MS (ESI+): m/z= 410.1 Yes [M+H] ⁺ , calc. for C ₂₀ H ₂₀ ClN ₇ O: 409.1.

Example 30: 6-chloro-2-(3-(methylamino)pyrrolidin-1-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4d]pyrimidin-4-amine.

The compound was prepared by the reaction of tert-butyl (1-(6-chloro-4-((thiophen-2-ylmethyl)amino)pyrido[3,4d]pyrimidin-2-yl)pyrrolidin-3-yl)(methyl)carbamate (obtained using the general synthesis method A) under the Boc deprotection conditions described above; RXH: Thiophen-2-ylmethanamine, 0.11 ml; t: 5 h; R3R2NH: 3-(N-tert-butoxycarbonyl-N-methylαamino)pyrrolidine/3-(N-Boc-N-methylamino)pyrrolidine,

- 28 044615

1.02 ml, 5 mmol, 5 eq.; t: 15 min. Automated flash chromatography (Heptane:EEAc, product elution 50:50% v/v) gave tert-butyl (1-(6-chloro-4-((thiophen-2-ylmethyl)amino)pyrido[3,4d ]pyrimidin-2-yl)pyrrolidin-3-yl)(methyl)carbamate as a yellow solid; weight: 404 mg; Yield: 80%; Purity: 94.1% (UHPLC-A); ¹ H-NMR (CDCf), δ (ppm): 8.65 (s, 1H), 7.36 (s, 1H), 7.23 (dd, 1H), 7.06 (d, 1H), 6 .96 (dd, 1H), 4.21 (t, NH), 4.95 (d, 2H), 3.94-3.87 (m, 2H), 3.65-3.53 (m, 2H ), 2.83 (s, 3H), 2.20-2.05 (m, 3H), 1.49 (s, 9H); LR-MS (ESI+): m/z= 476.0 Da [M+H] ⁺ , calc. for C22H27CWO2S: 475.0.

Method for removing Vos protection; tert-butyl (1-(6-chloro-4-((thiophen-2-ylmethyl)amino)pyrido[3,4d]pyrimidin-2-yl)pyrrolidin-3-yl)(methyl)carbamate (253 mg, 0 .5 mmol, 1 eq.); methanol (5 ml, 0.1 M); conc. HCl (0.15 ml, 1.5 mmol, 3 eq.), t: 12 h. Workup of the reaction mixture gave the title compound as a yellow solid; weight: 142 mg; Yield: 75%; Purity: 99.2% (UHPLC-V); ¹ H-NMR (CDCl3), δ (ppm): 8.63 (s, 1H), 7.34 (s, 1H), 7.22 (dd, 1H), 7.05 (d, 1H), 6 .95 (dd, 1H), 6.25 (t, NH), 4.91 (d, 2H), 3.89-3.65 (m, 3H), 3.53 (dd, 1H), 3. 37 (quint, 1H), 2.49 (s, 3H), 2.25-2.14 (m, 1H), 1.92-1.83 (m, 1H); LR-MS (ESI+): m/z= 375.0 Da [M+H] ⁺ , calc. for C ₁₇ H ₁₉ ClN ₆ S: 374.1.

Example 31: 6-chloro-N-(furan-2-ylmethyl)-2-(3-(methylamino)pyrrolidin-1-yl)pyrido[3,4d]pyrimidin-4-amine.

The compound was prepared by the reaction of tert-butyl (1-(6-chloro-4-((furan-2-ylmethyl)amino)pyrido[3,4d]pyrimidin-2-yl)pyrrolidin-3-yl)(methyl)carbamate (obtained using the general synthesis method A) under the Boc deprotection conditions described above; RXH: furan-2-ylmethanamine, 97.2 µl; t: 5 h; R ³ R ² NH: 3-(N-tert-butoxycarbonyl-N-methylamino)pyrrolidine/3-(N-Boc-N-methylamino)pyrrolidine, 1.02 ml, 5 mmol, 5 eq.; t: 15 min. Automated flash chromatography (Heptane:EtOAc, product elution 50:50% v/v) gave tert-butyl (1-(6-chloro-4-((furan-2-ylmethyl)amino)pyrido[3,4d ]pyrimidin-2-yl)pyrrolidin-3-yl)(methyl)carbamate as a yellow solid; weight: 386 mg; Yield: 83%; Purity: 98.7% (UHPLC-A); ¹ H-NMR (CDCl ₃ ), δ (ppm): 8.63 (s, 1H), 7.42 (s, 1H), 7.37 (dd, 1H), 6.34 (dd, 1H), 6.30 (dd, 1H), 4.86 br.s, NH), 4.76 (d, 2H), 3.93-3.84 (m, 2H), 3.62-3.50 (m , 2H), 2.83 (s, 3H), 2.19-2.05 (m, 3H), 1.49 (s, 9H); LR-MS (ESI+): m/z= 459.1 Yes [M+H] ⁺ , calc. for C22H27CMO3: 458.2.

Method for removing Vos protection; tert-butyl (1-(6-chloro-4-((furan-2-ylmethyl)amino)pyrido[3,4d]pyrimidin-2-yl)pyrrolidin-3-yl)(methyl)carbamate (230 mg, 0 .5 mmol, 1 eq.); methanol (5 ml, 0.1 M); conc. HCl (0.15 ml, 1.5 mmol, 3 eq.), t: 5 h. Workup of the reaction mixture gave the title compound as a yellow solid; weight: 134 mg; Yield: 90%; Purity: 98.4% (UHPLC-A); 1H-NMR ( _CDCl3 ), δ (ppm): 8.61 (d, 1H), 7.37 (dd, 1H), 7.35 (s, 1H), 6.34 (dd, 1H), 6 .31 (dd, 1H), 6.2 (t, NH), 4.72 (d, 2H), 3.87-3.74 (m, 2H), 3.70-3.61 (m, 1H ), 3.51 (dd, 1H), 3.38 (quint, 1H), 2.50 (s, 3H), 2.25-2.15 (m, 1H), 1.93-1.83 ( m, 1H); LR-MS (ESI+): m/z= 359.1 Yes [M+H] ⁺ , calc. for Ci7Hi9ClN ₆ O: 358.1.

Example 32: 6-chloro-2-(4-methyl-1,4-diazepan-1-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimidin-4 amine.

RXH: 2-thiophenemethylamine, 0.11 ml; t: 5 h; R3R2NH: 1-methylhomopiperazine, 0.26 ml, 2 mmol, 2 equiv.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 95:5% v/v) gave the title compound as a yellow solid; weight: 0.367 g; Yield: 89%; Purity: 98.5% (UHPLC-A); 1H-NMR (MeOD), δ (ppm): 8.52 (s, 1H), 7.81 (d, 1H), 7.21 (dd, 1H), 7.04 (d, 1H), 6. 94 (dd, 1H), 4.90 (s, 2H), 4.01 br.s, 2H), 3.92 br.s, 2H), 2.78 br.s, 2H), 2.70- 2.67 (m, 2H), 2.42 (s, 3H), 2.06 br.s, 2H); LR-MS (ESI+): m/z= 389.1 Yes [M+H] ⁺ , calc. for C ₁₈ H ₂₁ ClN ₆ S: 388.1.

Example 33: 6-chloro-N2-(2-(1-methylpyrrolidin-2-yl)ethyl)-N4-(thiophen-2-ylmethyl)pyrido[3,4d]pyrimidin-2,4-diamine.

RXH: 2-thiophenemethylamine, 0.11 ml; t: 5 h; R3R2NH: 2-(2-aminoethyl)-1-methylpyrrolidine, 0.30 ml, 2 mmol, 2 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 85:15% v/v) gave the title compound as a yellow solid; weight: 0.352 g; Yield: 87%; Purity: 99.2% (UHPLC-A); 1H-NMR (CDCf/MeOD 2:1), δ (ppm): 8.51 br.s, 1H), 7.75 br.s, 1H), 7.21 (dd, 1H), 7.06 ( d, 1H), 6.95 (dd, 1H), 4.92 brs, 2H), 3.55 (t, 2H), 3.23-3.16 (m, 1h),

- 29 044615

2.43 (s, 3H), 2.39-2.31 (m, 2H), 2.14-2.06 (m, 2H), 1.86-1.81 (m, 2H), 1. 69-1.62 (m, 2H); LR-MS (ESI+): m/z=

403.1 Yes [M+N] ⁺ , cal. for C ₁₉ H ₂₃ ClN ₆ S: 402.1.

Example 34: 2-(3-aminopyrrolidin-1-yl)-6-chloro-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimidin-4amine.

RXH: 2-thiophenemethylamine, 0.11 ml; t: 5 h; R3R2NH: 3-aminopyrrolidine, 0.18 ml, 2 mmol, 2 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 87:13% v/v) gave the title compound as a yellow solid; weight: 0.330 g; Yield: 90%; Purity: 98.2% (UHPLC-A); 1H-NMR (CDCl ₃ /MeOD 2:1), δ (ppm): 8.55 (s, 1H), 7.76 (s, 1H), 7.20 (dd, 1H), 7.07 (d , 1H), 6.94 (dd, 1H), 4.90 brs, 2H), 3.97-3.83 (m, 2H), 3.79-3.69 (m, 2H), 3 .50 (d, 1H), 2.33-2.22 (m, 1H), 1.92-1.86 (m, 1H); LR-MS (ESI+): m/z= 361.0 Da [M+H] ⁺ , calc. for Ci ₆ Hi7ClN ₆ S: 360.1.

Example 35: 2-(4-aminopiperidin-1-yl)-6-chloro-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimidin-4amine.

RXH: 2-thiophenemethylamine, 0.11 ml; t: 5 h; R3R2NH: 4-Aminopiperidine, 0.23 ml, 2 mmol, 2 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 70:30% v/v) gave the title compound as a yellow solid; weight: 0.167 g; Yield: 40%; Purity: 89.8% (UHPLC-A); 1H-NMR ( _CDCl3 ), δ (ppm): 8.63 (s, 1H), 7.27 (s, 1H), 7.25 (d, 1H), 7.07 (dd, 1H), 6 .98 (dd, 1H), 5.81 (t, NH), 4.95 (d, 2H), 4.87 (dt, 2H), 3.04 (td, 2H), 2.97 (tt, 1H), 1.93 (dm, 1H), 1.34 (ddd, 2H); LR-MS (ESI+): m/z= 375.0 Da [M+H] ⁺ , calc. for C^H^CMS: 374.1.

Example 36: 6-chloro-2-(4-(methylamino)niperidin-1-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimidin4-amine.

RXH: 2-thiophenemethylamine, 0.11 ml; t: 5 h; R3R2NH: 4-methylaminopiperidine, 240 mg, 2 mmol, 2 eq.; t: 15 min. Automated flash chromatography (EtOAc:MeOH, product elution 95:5% v/v) gave the title compound as a yellow solid; weight: 0.166 g; Yield: 35%; Purity: 81.7% (UHPLC-A); 1H-NMR ( _CDCl3 ), δ (ppm): 8.60 (s, 1H), 7.34 (s, 1H), 7.24 (dd, 1H), 7.05 (d, 1H), 6 .97 (dd, 1H), 6.18 (t, NH), 4.96 (dt, 2H), 4.91 (d, 2H), 2.98 (td, 2H), 2.89 (tt, 1H), 2.55 (s, 3H), 2.08 (dm, 1H), 1.53 (ddd, 2H); LR-MS (ESI+): m/z= 389.1 Yes [M+H] ⁺ , calc. for Ci8H ₂ iClN ₆ S: 388.1.

Example 37: 2-((6-chloro-2-(hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl)pyrido[3,4^]pyrimidin-4yl)amino)-N-phenylethan-1 -sulfonamide.

RXH: 2-amino-N-phenylethane-1-sulfonamide diazabicyclo[4.3.0]nonane, 0.27 ml, 2.1 mmol, hydrochloride, 225.7 mg; t: 12 h; R3R2NH: 1.42.1 eq; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 50:50% v/v) gave the title compound as a yellow solid; weight: 0.220 g; Yield: 40%; Purity: 88.7% (UHPLC-A); 1H NMR (CDCl ₃ ), δ (ppm): 8.40 (s, 1H), 7.49 br.s, 2H), 7.25-7.11 (m, 2H), 7.19 (s, 1H ), 7.06-6.98 (m, 1H), 4.73 (d, 1H), 4.55 (d, 1H), 3.94 br.s, 2H), 3.53 br.s, 3H), 3.41-3.11 (m, 3H), 3.02 (t, 1H), 2.60 (t, 2H), 2.04-1.79 (m, 3H), 1.73 -1.54 (m, 1H); LR-MS (ESI+): m/z= 488.1 Yes [M+H] ⁺ , calc. for C ₂₂ H ₂₆ ClN7O ₂ S: 487.2.

Example 38: 6-chloro-2-(hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl)-N-(2-(morpholinosulfonyl)ethyl)pi

- 30 044615 rido[3,4-d]pyrimudin-4-amine.

RXH: 3-(aminomethyl)indolin-2-one hydrochloride, 210 mg; t: 12 h; R3R2NH: 1,4Diazabicyclo[4.3.0]nonane, 0.27 ml, 2.1 mmol, 2.1 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 50:50% v/v) gave the title compound as a yellow solid; weight: 0.313 g; Yield: 54%; Purity: 83.2% (UHPLC-A); mp: decomposition of the compound was observed up to 67.3°C; ¹ H-NMR (CDCl3), δ (ppm): 8.54 (s, 1H), 7.44 (s, 1H), 7.01 (t, NH), 4.93 (d, 1H), 4 .78 (d, 1H), 4.10 (d, 2H), 3.78 (t, 4H), 3.42-3.27 (m, 6H), 3.26-3.14 (m, 3H ), 2.86 (t, 1H), 2.47-2.17 (m, 3H), 2.00-1.75 (m, 3H), 1.68-1.51 (m, 1H); LR-MS (ESI+): m/z= 482.1 Yes [M+H] ⁺ , calc. for C2oH ₂ 8C1N703S: 481.2.

Example 68: 6-chloro-2-(4-methylpiperazin-1-yl)-N-((3-methylthiophen-2-yl)methyl)pyrudo[3,4d]pyrimidin-4-amine.

RXH: (3-methylthiophen-2-yl)methanamine, 0.14 ml; t: 14 h; R3R2NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 95:05% v/v) gave the title compound as a brown solid; weight: 0.217 g; Yield: 51%; Purity: 91.3% (UHPLC-V); mp: 196.2-200.8°C; ¹ H-NMR (CDC13), δ (ppm): 8.62 (s, 1H), 7.28 (s, 1H), 7.17 (d, 1H), 6.85 (d, 1H), 5 .75 (t, NH), 4.86 (d, 2H), 3.98 (t, 4H), 2.50 (t, 4H), 2.36 (s, 3H), 2.28 (s, 3H); LR-MS (ESI+): m/z= 389.0 Da [M+H] ⁺ , calc. for Ci ₈ H2iC1N ₆ S: 388.1.

Example 69: 6-chloro-2-(4-methylpiperazin-1-yl)-N-((5-methylthiophen-2-yl)methyl)pyrudo[3,4d]pyrimidin-4-amine.

RXH: (5-methylthiophen-2-yl)methanamine, 0.13 ml; t: 2 h; R3R2NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 98:02% v/v) gave the title compound as a yellow solid; weight: 0.292 g; Yield: 75%; Purity: 99.9% (UHPLC-A); mp: 208.0-212.1°C; ¹ H-NMR (CDCl3), δ (ppm): 8.63 (s, 1H), 7.26 (s, 1H), 6.85 (d, 1H), 6.62 (dq, 1H), 5 .76 (t, NH), 4.86 (d, 2H), 3.98 (t, 4H), 2.50 (t, 4H), 2.45 (d, 3H), 2.36 (s, 3H); LR-MS (ESI+): m/z= 389.1 Yes [M+H] ⁺ , calc. for C18H ₂₁ ClN ₆ S: 388.1.

Example 70: 6-chloro-2-(4-methylpiperazin-1 -yl)-N-(2-(thiazol-2-yl)ethyl)pyrido[3,4-d]pyrimidin-4amine.

RXH: 2-(thiazol-2-yl)ethan-1-amine, 0.12 ml; t: 15.5 h; R3R2NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 96:04% v/v) gave the title compound as a yellow solid; weight: 0.265 g; Yield: 67.3%; Purity: 99.0% (UHPLC-V); mp: 184.7-188.7°C; ¹ H-NMR (CDCl3), δ (ppm): 8.53 (s, 1H), 7.71 (d, 1H), 7.28 (s, 1H), 7.20 (d, 1H), 6 .96 (t, NH), 3.95 (dd, 2H), 3.87 (t, 4H), 3.32 (t, 2H), 2.41 (t, 4H), 2.28 (s, 3H); LR-MS (ESI+): m/z= 390.0 Da [M+H] ⁺ , calc. for C17H ₂₀ ClN ₇ S: 389.1.

Example 71: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrumidin-4-yl)amino)ethane1-sulfonamide.

- 31 044615

RXH: 2-aminoethane-1-sulfonamide hydrochloride 168.0 mg; t: 2 h; R3R2NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 90:10% v/v) gave the title compound as a brown solid; weight: 0.262 g; Yield: 65%; Purity: 95.5% (UHPLC-V); ^1H -NMR (CDCl3:MeOD 70:30%v/v), δ (ppm): 8.48 (s, 1H), 7.56 (s, 1H), 3.94 (t, 2H) , 3.88 (t, 4H), 3.38 (t, 2H), 2.52 (t, 4H), 2.33 (s, 3H); LR-MS (ESI+): m/z= 386.1 Yes [M+H] ⁺ , calc. for C14H ₂₀ ClN ₇ O ₂ S: 385.1.

Example 72: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N-(2chlorophenyl)ethane-1-sulfonamide.

RXH: 2-amino-N-(2-chlorophenyl)ethane-1-sulfonamide hydrochloride, 290.0 mg; t: 2 h; R ³ R ² NH: 1methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 88:12% v/v) gave the title compound as a brown solid; weight: 0.303 g; Yield: 60.4%; Purity: 99.0% (UHPLC-V); mp: 210.5225.5°C; 1H-NMR (MeOD), δ (ppm): 8.47 (s, 1H), 7.73 (s, 1H), 7.56 (dd, 1H), 7.34 (dd, 1H), 7. 27 (td, 1H), 7.12 (td, 1H), 3.99 (t, 2H), 3.88 (t, 4H), 3.61 (t, 2H), 2.54 (t, 4H ), 2.39 (s, 3H); LR-MS (ESI+): m/z= 496.1 Yes [M+H] ⁺ , calc. for C20H23CFN7O2S: 495.1.

Example 73: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N-(otolyl)ethane-1-sulfonamide.

RXH: 2-amino-N-(o-tolyl)ethane-1-sulfonamide hydrochloride, 309.0 mg; t: 2 h; R3R2NH: 1methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 80:20% v/v) gave the title compound as a yellow solid; weight: 0.297 g; Yield: 61.8%; Purity: 98.9% (UHPLC-V); mp: 226.0-229.0°C; 1H-NMR (CDCl ₃ :MeOD 70:30%v/v), δ (ppm): 8.50 (s, 1H), 7.40 (s, 1H), 7.27 (d, 1H) , 7.10-6.99 (m, 3H), 3.94 (t, 2H), 3.79 (t, 4H), 3.43 (t, 2H), 2.39 (t, 4H), 2.26 (s, 3H), 2.21 (s, 3H); LR-MS (ESI+): m/z= 476.1 Yes [M+H] ⁺ , calc. for C ₂₁ H ₂₆ ClN ₇ O ₂ S: 475.2.

Example 74: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N-(2methoxyphenyl)ethane-1-sulfonamide.

RXH: 2-amino-N-(2-methoxyphenyl)ethane-1-sulfonamide hydrochloride, 308.8 mg; t: 16 h; R3R2NH: 1methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 80:20% v/v) gave the title compound as an orange solid; weight: 0.306 g; Yield: 56.0%; Purity: 90.0% (UHPLC-A); mp: 208.5213.6°C; 1H-NMR (MeOD), δ (ppm): 8.46 (s, 1H), 7.71 (s, 1H), 7.39 (d, 1H), 7.04 (t, 1H), 6. 89 (d, 1H), 6.84 (d, 1H), 3.95 (t, 2H), 3.83 (t, 4H), 3.70 (s, 3H), 3.57 (t, 2H ), 2.47 (t, 4H), 2.35 (s, 3H); LR-MS (ESI+): m/z= 492.0 Da [M+H] ⁺ , calc. for C ₂₁ H ₂₆ ClN ₇ O ₃ S: 491.2.

Example 75: N-(2-aminophenyl)-2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4- 32 044615 yl)amino)ethane- 1-sulfonamide.

RXH: 2-amino-N-(2-aminophenyl)ethane-1-sulfonamide dihydrochloride, 281.0 mg; t: 2 h; R3R2NH: 1methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 20 min. Automated flash chromatography (CHCl ₃ :EtOH, product elution 85:15% v/v) gave the title compound as a yellow solid; weight: 0.279 g; Yield: 57.7%; Purity: 98.2% (UHPLC-V); mp: 223.8-232.2°C; 1H-NMR (CDCl ₃ :MeOD 70:30%v/v), δ (ppm): 8.26 (s, 1H), 7.42 (s, 1H), 6.87 (dd, 1H) , 6.78 (dd, 1H), 6.53 (dd, 1H), 6.42 (dd, 1H), 3.75 (t, 2H), 3.61 (t, 4H), 3.25 ( t, 2H), 2.20 (t, 4H), 2.10 (s, 3H); LR-MS (ESI+): m/z= 477.2 Da [M+H] ⁺ , calc. for C20H25CMO2S: 476.2.

Example 76: 2-((6-chloro-2-(4-methylpiperαzin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N-(3chlorophenyl)ethane-1-sulfonamide.

RXH: 2-amino-N-(3-chlorophenyl)ethane-1-sulfonamide hydrochloride, 289.9 mg; t: 2 h; R3R2NH: 1methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 90:10% v/v) gave the title compound as a yellow solid; weight: 0.287 g; Yield: 56.0%; Purity: 96.8% (UHPLC-V); mp: 203.0-205.0°C; 1H-NMR (CDCl ₃ :MeOD 70:30%v/v), δ (ppm): 8.46 (s, 1H), 7.46 (s, 1H), 7.06-6.90 ( m, 4H), 3.87 (t, 2H), 3.74 (t, 4H), 3.46 (t, 2H), 2.38 (t, 4H), 2.26 (s, 3H); LR-MS (ESI+): m/z= 496.0 Yes [M+H]+, calc. for C2oH23Cl ₃ N702S: 495.1.

Example 77: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)αmino)-N-(3(trifluoromethoxy)phenyl)ethane- 1-sulfonamide.

RXH: 2-amino-N-(3-(trifluoromethoxy)phenyl)ethane-1-sulfonamide hydrochloride, 359.8 mg; t: 17 h; R3R2NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 95:05% v/v) gave the title compound as a yellow solid; weight: 0.278 g; Yield: 47.2%; Purity: 92.5% (UHPLC-A); mp: 185.7-189.5°C; ^1H -NMR (CDCl3:MeOD 70:30%v/v), δ (ppm): 8.45 (s, 1H), 7.49 (s, 1H), 7.15 (sq, 1H) , 7.03-6.95 (m, 2H), 6.83 (dt, 1H), 3.89 (t, 2H), 3.78 (t, 4H), 3.46 (t, 2H), 2.42 (t, 4H), 2.29 (s, 3H); LR-MS (ESI+): m/z= 546.0 Da [M+H] ⁺ , calc. for C2iH2 ₃ ClF ₃ N ₇ O ₃ S: 545.1.

Example 78: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)αmino)-N-(3(trifluoromethyl)phenyl)ethane- 1-sulfonamide.

RXH: 2-amino-N-(3-(trifluoromethyl)phenyl)ethane-1-sulfonamide hydrochloride, 337.5 mg; t: 2 h; R3R2NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 95:05% v/v) gave the title compound as a brown solid; weight: 0.495 g; Yield: 86.0%; Purity: 92.1% (UHPLC-A);

mp: 211.0-213.0°C; 1H-NMR ( _CDCl3 ), δ (ppm): 8.62 (s, 1H), 7.45-7.38 (m, 4H), 7.17 (s, 1H), 6.26 (t, NH), 4.10 (sq, 2H), 3.87 (t, 4H), 3.56 (t, 2H), 2.44 (t, 4H), 2.34 (s, 3H); LR-MS (ESI+): m/z= 530.0 Da [M+H] ⁺ , calc.

for C21H23CT3N7O2S: 529.1.

Example 79: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N-(mtolyl)ethane-1-sulfonamide.

RXH: 2-amino-N-(m-tolyl)ethane-1-sulfonαmide hydrochloride, 292.5 mg; t: 13.5 h; R3R2NH: 1methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 80:20% v/v) gave the title compound as a yellow solid; weight: 0.338 g; Yield: 69.2%; Purity: 97.4% (UHPLC-A); mp: 210.7-214.2°C; ¹ H-NMR (MeOD), δ (ppm): 8.47 (s, 1H), 7.73 (s, 1H), 7.10 (t, 1H), 6.97-6.84 (m, 3H), 3.94 (t, 2H), 3.81 (t, 4H), 3.58 (t, 2H), 2.42 (t, 4H), 2.33 (s, 3H), 2. 19 (s, 3H); LR-MS (ESI+): m/z= 476.1 Yes [M+H] ⁺ , calc. for C ₂ 1H ₂₆ ClN7O ₂ S: 475.2.

Example 80: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N-(3methoxyphenyl)ethane-1-sulfonamide.

RXH: 2-amino-N-(3-methoxyphenyl)ethane-1-sulfonamide hydrochloride, 296.7 mg; t: 4.5 h; R3R2NH: 1methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 80:20% v/v) gave the title compound as a yellow solid; weight: 0.254 g; Yield: 49.7%; Purity: 96.4% (UHPLC-A); mp: 215.7-217.0°C; ^1H -NMR (CDCl3:MeOD 70:30%v/v), δ (ppm): 8.36 (s, 1H), 7.42 (s, 1H), 6.95 (t, 1H) , 6.56-6.40 (m, 3H), 3.80 (t, 2H), 3.66 (t, 4H), 3.56 (s, 3H), 3.38 (t, 2H), 2.30 (t, 4H), 2.18 (s, 3H); LR-MS (ESI+): m/z= 492.1 Yes [M+H] ⁺ , calc. for C21H ₂₆ ClN7O3S: 491.2.

Example 81: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N-(3(methylthio)phenyl)ethane- 1-sulfonamide.

RXH: 2-amino-^(3-(methylthio)phenyl)ethane-1-sulfonamide hydrochloride, 310.6 mg; t: 16.5 h; R3R2NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 80:20% v/v) gave the title compound as a pale brown solid; weight: 0.453 g; Yield: 82.0%; Purity: 91.9% (UHPLC-A); mp: 122.1-137.4°C; 1H-NMR (CDCl ₃ :MeOD 70:30%v/v), δ (ppm): 8.62 (s, 1H), 7.23-7.17 (m, 2H), 7.02- 6.90 (m, 3H), 6.28 (t, NH), 4.07 (dd, 2H), 3.87 (t, 4H), 3.55 (dd, 2H), 2.45 (t , 4H), 2.43 (s, 3H), 2.34 (s, 3H); LR-MS (ESI+): m/z= 508.0 Da [M+H] ⁺ , calc. for C ₂₁ H ₂₆ ClN ₇ O ₂ S ₂ : 507.1.

Example 82: 2-((6-chloro-2-(4-methylpiperαzin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N-(4chlorophenyl)ethane-1-sulfonamide.

- 34 044615

RXH: 2-amino-N-(4-chlorophenyl)ethane-1-sulfonamide hydrochloride, 309.7 mg; t: 3 h; R ³ R ² NH: 1methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 96:04% v/v) gave the title compound as a yellow solid; weight: 0.180 g; Yield: 35.9%; Purity: 98.8% (UHPLC-A); mp: 232.1-241.2°C; ¹ H-NMR (MeOD), δ (ppm): 8.46 (s, 1H), 7.71 (s, 1H), 7.22 (d, 2H), 7.11 (d, 2H), 3 .93 (t, 2H), 3.81 (t, 4H), 3.56 (t, 2H), 2.44 (t, 4H), 2.35 (s, 3H); LR-MS (ESI+): m/z= 496.0 Da [M+H] ⁺ , calc. for C ₂ oH23C12^023: 495.1.

Example 83: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N-(4(trifluoromethyl)phenyl)ethane- 1-sulfonamide.

RXH: 2-amino-N-(4-(trifluoromethyl)phenyl)ethane-1-sulfonamide hydrochloride, 329.8 mg; t: 2 h; R ³ R ² NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 95:05% v/v) gave the title compound as a yellow solid; weight: 0.246 g; Yield: 43.7%; Purity: 94.0% (UHPLC-A); mp: 214.5-221.5°C; 1H-NMR (MeOD), δ (ppm): 8.44 (s, 1H), 7.70 (s, 1H), 7.46 (d, 2H), 7.22 (d, 2H), 3. 96 (t, 2H), 3.81 (t, 4H), 3.61 (t, 2H), 2.41 (t, 4H), 2.31 (s, 3H); LR-MS (ESI+): m/z= 530.0 Yes [M+N] ⁺ , calc. for C ₂₁ H ₂₃ ClF ₃ N ₇ O ₂ S: 529.1.

Example 84: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N-(ptolyl)ethane-1-sulfonamide.

RXH: 2-amino-N-(p-tolyl)ethane-1-sulfonamide hydrochloride, 294.8 mg; t: 3 h; R3R2NH: 1methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 85:15% v/v) gave the title compound as a pale yellow solid; weight: 0.463 g; Yield: 92.0%; Purity: 94.6% (UHPLC-A); mp: 201.5-206.1°C; 1H-NMR (CDCM, δ (ppm): 8.63 (s, 1H), 7.21 (s, 1H), 7.15-7.03 (m, 4H), 4.08 (dd, 2H) , 3.87 (t, 4H), 3.49 (dd, 2H), 2.45 (t, 4H), 2.34 (s, 3H), 2.31 (s, 3H); LR-MS ( ESI+): m/z= 476.1 Da [M+H] ⁺ , calculated for C21H26CMO2S: 475.2.

Example 85: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N-(4(methylthio)phenyl)ethane- 1-sulfonamide.

RXH: 2-amino-N-(4-(methylthio)phenyl)ethane-1-sulfonamide hydrochloride, 270.5 mg; t: 17 h; R ³ R ² NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 80:20% v/v) gave the title compound as

- 35 044615 pale yellow solid; weight: 0.248 g; Yield: 46.4%; Purity: 95.0% (UHPLC-A); mp:

228.5-233.0°C; ¹ H-NMR (MeOD), δ (ppm): 8.47 (s, 1H), 7.73 (s, 1H), 7.14-7.06 (m, 4H), 3.94 (t, 2H), 3.81 (t,

4H), 3.57 (t, 2H), 2.45 (t, 4H), 2.43 (s, 3H), 2.34 (s, 3H); LR-MS (ESI+): m/z= 508.0 Da [M+H] ⁺ , calc. For

C ₂₁ H ₂₆ ClN ₇ O ₂ S ₂ : 507.1.

Example 86: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N(pyridin-3-yl)ethan-1 -sulfonamide.

RXH: 2-amino-K-(pyridin-3-yl)ethane-1-sulfonamide hydrochloride, 277.9 mg; t: 2 h; R3R2NH: 1methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 30 min. Automated flash chromatography (EAAc:McOH, product elution 75:25% v/v) gave the title compound as a yellow solid; weight: 0.178 g; Yield: 36.3%; Purity: 94.7% (UHPLC-V); mp: 196.0-199.1°C; 1H-NMR (CDCl ₃ :MeOD 70:30%v/v), δ (ppm): 8.43 (s, 1H), 8.31 (d, 1H), 8.21 (dd, 1H) , 7.58 (dd, 1H), 7.40 (s, 1H), 7.15 (dd, 1H), 3.92 (t, 2H), 3.78 (t, 4H), 3.46 ( s, 2H), 3.37 (t, NH), 2.44 (t, 4H), 2.30 (s, 3H); LR-MS (ESI+): m/z= 463.2 Da [M+H] ⁺ , calc. for C^ON^S: 462.1.

Example 87: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N-(6chloropyridin-2-yl)ethane- 1-sulfonamide.

RXH: 2-amino-N-(6-chloropyridin-2-yl)ethane-1-sulfonamide hydrochloride, 303.0 mg; t: 2 h; R3R2NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 90:10% v/v) gave the title compound as a pale yellow solid; weight: 0.440 g; Yield: 85%; Purity: 96.0% (UHPLC-V); mp: 252.6254.0°C; 1H-NMR (CDCl ₃ :MeOD 70:30%v/v), δ (ppm): 8.41 (s, 1H), 7.52 (s, 1H), 7.47 (s, NH) , 7.40 (t, 1H), 6.67 (dd, 2H), 3.95 (t, 2H), 3.84 (t, 2H), 3.82 (t, 4H), 3.29 ( s, NH), 2.47 (t, 4H), 2.30 (s, 3H); LR-MS (ESI+): m/z= 497.1 Yes [M+H] ⁺ , calc. for C^C^N^S: 496.1.

Example 88: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N(pyridin-2-ylmethyl)ethane-1 -sulfonamide.

RXH: 2-amino-N-(pyridin-2-ylmethyl)ethane-1-sulfonamide hydrochloride, 272.5 mg; t: 3.5 h; R3R2NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 91:09% v/v) gave the title compound as a yellow solid; weight: 0.326 g; Yield: 67.7%; Purity: 99.1% (UHPLC-A); mp: 196.5-197.2°C; 1H-NMR (CDCl ₃ :MeOD 70:30%v/v), δ (ppm): 8.56 (s, 1H), 8.51 (d, 1H), 7.69 (t, 1H) , 7.27 (s, 1H), 7.257.20 (m, 2H), 7.10 (t, NH), 4.49 (s, 2H), 4.06 (t, 2H), 3.90 ( t, 4H), 3.41 (t, 2H), 2.47 (t, 4H), 2.34 (s, 3H); LRMS (ESI+): m/z= 477.1 Da [M+H] ⁺ , calc. for C ₂ 0H ₂ 5ClN8O ₂ S: 476.2.

Example 89: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N(pyrimidin-2-yl)ethan-1 -sulfonamide.

- 36 044615

RXH: 2-amino-N-(pyrimidin-2-yl)ethane-1-sulfonamide hydrochloride, 311.5 mg; t: 2 h; R3R2NH: 1methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 20 min. Automated flash chromatography (DCM:MeOH, product elution 90:20% v/v) gave the title compound as a pale yellow solid; weight: 0.109 g; Yield: 23.5%; Purity: 99.6% (UHPLC-V); mp: 256.6263.8°C; ¹ H-NMR (MeOD), δ (ppm): 8.44 (s, 1H), 8.32 (d, 2H), 7.84 (s, NH), 7.66 (s, 1H), 6 .81 (t, 1H), 4.063.93 (m, 4H), 3.90 (t, 3H), 2.56 (t, 4H), 2.39 (s, 3H); LR-MS (ESI+): m/z= 464.1 Yes [M+H] ⁺ , calc. for Ci8H22ClN9O2S: 463.1.

Example 90: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N(1,3-dimethyl-1 H- pyrazol-5-yl)ethane-1-sulfonamide.

RXH: 2-amino-N-(1,3-dimethyl-1H-pyrazol-5-yl)ethane-1-sulfonamide hydrochloride, 295.2 mg; t: 2 h; R3R2NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 75:25% v/v) gave the title compound as a pale red solid; weight: 0.128 g; Yield: 25.0%; Purity: 93.6% (UHPLC-V); ¹ H-NMR (MeOD), δ (ppm): 8.61 (s, 1H), 7.31 (s, 1H), 6.47 (t, NH), 5.88 (s, 1H), 4 .12 (dd, 2H), 3.92 (t, 4H), 3.80 (s, 3H), 3.54 (dd, 2H), 2.54 (t, 4H), 2.40 (s, 3H), 2.20 (s, 3H); LR-MS (ESI+): m/z= 480.2 Da [M+H] ⁺ , calc. for C ₁₉ H ₂₆ ClN ₉ O ₂ S: 479.2.

Example 91: N-benzyl-2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)N-(2-hydroxyethyl)ethane -1-sulfonamide.

The compound was obtained by the reaction of N-benzyl-N-(2-((tert-butyldimethylsilyl)oxy)ethyl)-2-((6-chloro-2-(4methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin- 4-yl)amino)ethane-1-sulfonamide (prepared by General Synthesis Method A) under the silyl-deprotecting conditions described below; RXH: 2-amino-N-benzyl-N(2-((tert-butyldimethylsilyl)oxy)ethyl)ethane-1-sulfonamide, 391.2 mg; t: 2 h; R3R2NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 30 min. Automated flash chromatography (DCM:MeOH, product elution 95:05% v/v) gave N-benzyl-N-(2-((tert-butyldimethylsilyl)oxy)ethyl)-2-((6-chloro- 2-(4methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)ethane-1-sulfonamide as a yellow solid; weight: 0.544 g; Yield: 83.0%; Purity: 96.8% (UHPLC-V); mp: 89.9-94.6°C; 1H-NMR (CDC13), δ (ppm): 8.64 (s, 1H), 7.33 (s, 1H), 7.32 (m, 5H), 6.60 (t, NH), 4. 50 (s, 2H), 4.07 (dd, 2H), 3.92 (t, 4H), 3.73 (t, 2H), 3.37 (dd, 4H), 2.47 (t, 4H ), 2.35 (s, 3H), 0.89 (s, 9H), 0.07 (s, 6H),; LR-MS (ESI+): m/z= 634.2 Da [M+H] ⁺ , calc. for C ₂₉ H ₄₄ ClN ₇ O ₃ SSi: 633.3.

Method for removing silyl protection; N-benzyl-N-(2-((tertbutyldimethylsilyl)oxy)ethyl)-2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidine) was loaded into a round-bottom flask -4yl)amino)ethane-1-sulfonamide (217 mg, 0.342 mmol, 1 eq.), THF (20 ml, 0.017 M) and TBAF (411 μl, 0.411 mmol, 1.2 eq.), The mixture was stirred at 23 °C for 85 min. The progress of the reaction was confirmed by TLC (DCM:MeOH, 85:15% v/v). Workup of the reaction mixture provided the title compound as a white solid; weight: 24 mg; Yield: 13.2%; Purity: 97.9% (UHPLC-V); mp: 157.5-161.3°C; 1H-NMR ( _CDCl3 ), δ (ppm): 8.56 (s, 1H), 7.31 (s, 1H), 7.28-7.21 (m, 5H), 6.71 (t, NH), 4.39 (s, 2H), 4.18 (dd, 2H), 3.85 (t, 4H), 3.68 (t, 2H), 3.38 (dd, 4H), 2. 41 (t, 4H), 2.28 (s, 3H); LR-MS (ESI+): m/z= 520.1 Da [M+H] ⁺ , calc. for C ₂₃ H ₃₀ ClN ₇ O ₃ S: 519.2.

Example 92: N-(2-aminoethyl)-N-benzyl-2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4d]pyrimidin-4-yl)amino)ethane- 1-sulfonamide.

- 37 044615

The compound was obtained by the reaction of tert-butyl (2-((N-benzyl-2-((6-chloro-2-(4-methylpiperazin-1yl)pyrido[3,4-d]pyrimidin-4-yl)amino)ethyl) sulfonamido)ethyl)carbamate (obtained using General Synthesis Method A) under the Boc deprotection conditions described above; RXH: tert-butyl (2-((2amino-N-benzylethyl)sulfonamido)ethyl)carbamate, 278.8 mg; t: 3 h; R ³ R ² NH: 1-methylpiperazine, 0.66 ml, 5.8 mmol, 7.8 eq.; t: 30 min. Automated flash chromatography (DCM:MeOH, product elution 92:08% v/v) gave tert-butyl (2-((N-benzyl-2-((6-chloro-2-(4-methylniperazin-1yl )pyrido[3,4-d]pyrimidin-4-yl)amino)ethyl)sulfonamido)ethyl)carbamate as a yellow solid; weight: 405 mg; Yield: 88.0%; Purity: 99.3% (UHPLC-V); mp: 86.7-92.3°C; ¹ H-NMR (CDCl3), δ (ppm): 8.51 (s, 1H), 7.33 (s, 1H), 7.25 (m, 5H), 6.76 br.s, NH), 4.86 (s, 1H), 4.40 (s, 2H), 3.97 (dd, 2H), 3.83 (t, 4H), 3.30-3.22 (m, 4H), 3 .16 (dd, 2H), 2.40 (t, 4H), 2.27 (s, 3H), 1.35 (s, 9H); LR-MS (ESI+): m/z= 619.2 Da [M+H] ⁺ , calc. for C28H ₃ 9ClN ₈ O4S: 618.3.

Method for removing Vos-protection; The pW μW reactor was loaded with tert-butyl (2-((N-benzyl-2-((6-chloro-2(4-methylpiperazin-1 -yl)pyrido[3,4-th]pyrimidin-4-yl)amino )ethyl)sulfonamido)ethyl)carbamate (101 mg, 0.162 mmol, 1 eq.), methanol (2.5 ml, 0.07 M) and TFA ((102 μl, 1.312 mmol, 8.1 eq.), The mixture was homogenized by stirring and reacted under microwave irradiation at 120°C for 45 min (energy power: 50 W). The progress of the reaction was confirmed by TLC (EtOAc:MeOH, 85:15% v/v). Workup of the reaction mixture gave title compound as a yellow solid; mass: 69 mg; Yield: 80%; Purity: 97.6% (UHPLC-V); mp: 158.0162.0°C; ¹ H-NMR (CDCl3), δ (ppm): 8.62 (s, 1H), 7.40 (s, 1H), 7.34 (t, NH), 7.31-7.26 (m, 5H), 4.38 (s , 2H), 4.06 (dd, 2H), 3.92 (t, 4H), 3.41 (dd, 2H), 3.37 (t, 2H), 2.82 (t, 2H), 2 .48 (t, 4H), 2.35 (s, 3H) LR-MS (ESI+): m/z= 519.1 Da [M+H] ⁺ , calculated for C23H3iClN8O3S: 518.2.

Example 93: 6-chloro-2-(4-methylpinerazin-1-yl)-N-(2-(phenylsulfonyl)ethyl)nirido[3,4d]pyrimidin-4-amine.

RXH: 2-(phenylsulfonyl)ethane-1-amine hydrochloride, 258.7 mg; t: 18 h; R3R2NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 85:15% v/v) gave the title compound as a brown solid; weight: 0.279 g; Yield: 62.0%; Purity: 99.4% (UHPLC-V); mp: 141.5-151.1°C; ¹ H-NMR (CDCl ₃ ), δ (ppm): 8.61 (s, 1H), 7.95 (d, 2H), 7.78-7.50 (m, 4H), 6.40 (t , NH), 4.07 (dd, 2H), 3.87 (t, 4H), 3.51 (dd, 2H), 2.46 (t, 4H), 2.35 (s, 3H); LR-MS (ESI+): m/z= 447.0 Da [M+H] ⁺ , calc. for C20H23CMO2S: 446.1.

Example 94: N-(2-(benzylsulfonyl)ethyl)-6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4d]pyrimidin-4-amine.

RXH: 2-(benzylsulfonyl)ethan-1-amine, 220.0 mg; t: 23 h; R3R2NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 80:20% v/v) gave the title compound as a white solid; weight: 0.315 g; Yield: 67.7%; Purity: 99.2% (UHPLC-V); mp: 217.9-221.1°C; ¹ H-NMR (CDCl3), δ (ppm): 8.63 (s, 1H), 7.38-7.35 (m, 5H), 7.25 (s, 1H), 6.30 (t, NH), 4.33 (s, 2H), 4.06 (dd, 2H), 3.88 (t, 4H), 3.26 (dd, 2H), 2.46 (t, 4H), 2. 35 (s, 3H); LR-MS (ESI+): m/z= 461.0 Da [M+H] ⁺ , calc. for C21H2 ₅ ClN ₆ O2S: 460.1.

Example 95: N-(2-(benzylsulfinyl)ethyl)-6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4d]nirimidin-4-amine.

- 38 044615

RXH: 2-(benzylsulfinyl)ethan-1-amine, 202.6 mg; t: 6 h; R3R2NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 80:20% v/v) gave the title compound as a yellow solid; weight: 0.188 g; Yield: 40.8%; Purity: 97.6% (UHPLC-V); mp: 200.7-203.2°C; ¹ H-NMR (CDCl3), δ (ppm): 8.62 (s, IH), 7.41-7.27 (m, 6H), 7.13 (t, NH), 4.26-4, 01 (m, 4H), 3.89 (t, 4H), 3.13-3.02 (m, 1H), 2.93-2.81 (m, 1H), 2.46 (t, 4H) , 2.35 (s, 3H); LR-MS (ESI+): m/z= 445.1 Yes [M+H] ⁺ , calc. for C2iH ₂ 5ClN ₆ OS: 444.2.

Example 96: 3-((6-chloro-2-(4-methylpiperazin-1-yl)nirido[3,4-d]pyrimidin-4-yl)amino)-Nphenylpropanamide.

RXH: 3-amino-N-phenylpropanamide, 189.5 mg; t: 2 h; R3R2NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 80:20% v/v) gave the title compound as a brown solid; weight: 0.315 g; Yield: 72.7%; Purity: 98.3% (UHPLC-V); mp: 206.6-210.6°C; ¹ H-NMR (CDCl ₃ :MeOD 90:10%v/v), δ (ppm): 8.53 (s, 1H), 7.68 (s, 1H), 7.51 (d, 2H ), 7.31 (t, 2H), 7.10 (t, IH), 4.02-3.88 (m, 6H), 2.79 (t, 2H), 2.56 (t, 4H) , 2.39 (s, 3H); LR-MS (ESI+): m/z= 426.1 Yes [M+H] ⁺ , calc. for C2iH24ClN7O: 425.2.

Example 97: 2-((6-chloro-2-(4-methylpiperazin-1-yl)nirido[3,4-d]pyrimidin-4-yl)amino)-Nphenylacetamide.

RXH: 2-amino-N-phenylacetamide hydrochloride, 166.0 mg; t: 20 h; R3R2NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 20 min. Automated flash chromatography (EtOAc:MeOH, product elution 80:20% v/v) gave the title compound as a brown solid; weight: 0.251 g; Yield: 56.3%; Purity: 92.5% (UHPLC-V); mp: 257.4-268.7°C; ^1H -NMR (CDCl3:MeOD 90:10%v/v), 5(ppm): 8.52 (s, 1H), 7.78 (s, 1H), 7.56 (d, 2H) , 7.32 (t, 2H), 7.12 (t, 1H), 4.25 (s, 2H), 3.88 (t, 4H), 2.39 (t, 4H), 2.27 ( s, 3H); LR-MS (ESI+): m/z= 412.1 Yes [M+H] ⁺ , calc. for C20H ₂₂ ClN ₇ O: 411.2.

Example 98: 3-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-Nmethylpropanamide.

RXH: 3-amino-N-methylpropanamide, 107.3 mg; t: 16.5 h; R ³ R ² NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 80:20% v/v) gave the title compound as a pale brown solid; weight: 0.295 g; Yield: 79.0%; Purity: 97.4% (UHPLC-A); mp: 227.6-235.3°C; ¹ H-NMR (MeOD), δ (ppm): 8.43 (s, IH), 7.75 (s, IH), 3.90 (t, 4H), 3.81 (t, 2H), 2 .71 (s, 3H), 2.56 (t, 2H), 2.50 (t, 4H), 2.33 (s, 3H); LR-MS (ESI+): m/z= 364.1 Yes [M+H] ⁺ , calc. for C ₁₆ H ₂₂ ClN ₇ O: 363.2.

Example 99: 2-((6-chloro-2-(4-methylpiperazin-1 -yl)pyrido[3,4-d]pyrimidin-4-yl)amino)acetamide.

- 39 044615

RXH: 2-aminoacetamide, 79.4 mg; t: 16.5 h; R3R2NH: 1-methylpiperazine, 0.88 ml, 7.8 mmol, 7.8 eq.; t: 30 min. Automated flash chromatography (EtOAc:MeOH, product elution 70:30% v/v) gave the title compound as a yellow solid; weight: 0.069 g; Yield: 20.3%; Purity: 98.6% (UHPLC-A); mp: 237.1-241.8°C; ¹ H-NMR (MeOD), δ (ppm): 8.52 (s, 1H), 7.76 (s, 1H), 7.47 (s, 2H(NH ₂ )), 4.11 (s, 2H), 3.88 (t, 4H), 3.35 (s, NH), 2.47 (t, 4H), 2.31 (s, 3H); LR-MS (ESI+): m/z= 336.0 Da [M+H] ⁺ , calc. for CnH^Cl^O: 335.1.

Step 8: Synthesis of intermediates G.

General synthesis method B:

Cl

Cl

RNH ₂ DIPEA, 22 °C, t ( ^h ) _C | EtOAc/DCM (1:1) (0.14M)

NHR

Cl

G1-G5

2,4,6-trichloropyrido[3,4-th]pyrimidine (intermediate F) (936 mg, 4 mmol, 1 eq.) was suspended in a solvent mixture [EtOAc:DCM (1:1), 28 ml. 0.14 M] in a round bottom flask with a stirrer in an Ar atmosphere. N,N-Diisopropylethylamine (2.04 mL, 2.9 mmol, 2.9 eq.) was then added and the mixture was homogenized by stirring for 5 min. The appropriate amine (RNH2) (4.1 mmol, 1.025 eq) was added and the resulting mixture was stirred at 22° C. until intermediate F was completely converted (5-20 h). The reaction was monitored by TLC (heptane:EtOAc). Volatiles were removed under reduced pressure and the residue was dissolved in EtOAc (150 ml), washed with water (3x50 ml), dried over anhydrous Na ₂ SO ₄ and filtered. The solvent was removed under reduced pressure to give a tan oil, which was purified by automated flash chromatography (heptane:EtOAc:DCM) to give the corresponding intermediate (G1-G5).

The following compounds were prepared according to the general synthesis method B described above for intermediates G.

Intermediate G1: 2,6-dichloro-N-(thiophen-2-ylmethyl)pyrido[3,4-d]nirimidin-4-amine.

RNH ₂ : Thiophen-2-ylmethanamine, 0.43 ml; t: 15 h; Automated flash chromatography (heptane:EtOAc:DCM, product elution 80:10:10% v/v) gave intermediate G1 as a pale yellow solid; weight: 1.06 g; Yield: 85%; Purity: 99.6% (UHPLC-V); mp: 168.7172.3°C; ¹ H-NMR (CDCl ₃ ), δ (ppm): 8.98 (s, 1H), 7.56 (s, 1H), 7.30 (dd, 1H), 7.14 (d, 1H), 7.00 (dd, 1H), 6.36 (t, NH), 5.04 (d, 2H); LR-MS (ESI+): m/z= 311.0 Da [M+H] ⁺ , calc. for C^Cl^S: 310.0.

Intermediate G2: 2,6-dichloro-N-(2-(morpholinosulfonyl)ethyl)πpyrido[3,4-d]pyrimidin4-amine.

RNH2: 2-amino-N-phenylethane-1-sulfonamide hydrochloride, 881.3 mg; t: 12 h; Automated flash chromatography (heptane:EtOAc:DCM, product elution 40:30:30% v/v) gave intermediate G2 as a yellow solid; weight: 1.22 g; Yield: 77%; Purity: 99.2% (UHPLC-V); mp: 236.7-240.4°C; ¹ H-NMR (MeOH), δ (ppm): 8.74 (s, 1H), 7.96 (s, 1H), 4.04 (t, 2H), 3.76 (t, 4H), 3 .43 (t, 2H), 3.32 (t, 4H); LR-MS (ESI+): m/z= 392.0 Da [M+H] ⁺ , calc. for C ₁₃ H ₁₅ Cl ₂ N ₅ O ₃ S: 391.0.

Intermediate G3: 2-((2,6-dichloronirido[3,4-d]pyrimidin-4-yl)amino)-N-phenylethan1-sulfonamide.

RNH2: 2-amino-N-phenylethane-1-sulfonamide hydrochloride, 881.30 mg; t: 12 h; Automated

- 40 044615 flash chromatography (heptane:EtOAc:DCM, product elution 70:15:15%v/v) gave intermediate G3 as a pale yellow solid; weight: 1.67 g; Yield: 93%; Purity: 88.6% (UHPLC-V); ¹ H-NMR (CDCI3), δ (ppm): 8.80 (s, 1H), 7.99 (s, 1H), 7.21-7.18 (m, 5H), 7.04 (t, NH), 4.04 (t,

2H), 3.57 (t, 2H); LR-MS (ESI+): m/z= 311.0 Da [M+H] ⁺ , calc. for C15H13CI2N5O2S: 397.0.

Intermediate G4: 2-((2,6-dichloropyrido[3,4-d]pyrimidin-4-yl)amino)-N-methyl-Nphenylethane-1-sulfonamide.

RNH ₂ : 2-amino-N-methyl-N-phenylethane-1-sulfonamide hydrochloride, 1.144 g; t: 10 h; Automated flash chromatography (Heptane:EtOAc:DCM, product elution 70:15:15% v/v) gave intermediate G4 as a pale yellow solid; weight: 1.53 g; Yield: 90%; Purity: 97.3% (UHPLC-V); mp: 184.3-203.4°C; ^1H -NMR ( _CDCl3 ), δ (ppm): 8.91 (s, 1H), 7.84 (s, 1H), 7.46-7.36 (m, 5H), 7.29 (t , NH), 4.03 (t, 2H), 3.46 (t, 2H), 3.39 (s, 3H); LR-MS (ESI+): m/z= 412.1 Yes [M+H] ⁺ , calc. for C16H15CI2N5O2S: 411.0.

Intermediate G5: 3-(((2,6-dichloropyrido[3,4-yl]pyrimidin-4-yl)amino)methyl)indolin-2one.

RNH2: 3-(aminomethyl)indolin-2-one hydrochloride, 800 mg; t: 20 h. Automated flash chromatography (Heptane:EtOAc:DCM, product elution 60:20:20% v/v) gave intermediate G5 as a yellow solid; weight: 0.553 g; Yield: 37%; Purity: 96.4% (UHPLC-V); mp: 202.2-206.8°C; ^1H -NMR (MeOD), δ (ppm): 8.82 (s, 1H), 8.12 (s, 1H), 7.34 (d, 1H), 7.22 (t, 1H), 7 .01 (t, 1H), 6.91 (t, 1H),

4.11 (dd, 2H), 3.97 (t, 1H); LR-MS (ESI+): m/z= 360.0 Da [M+H] ⁺ , calc. for C ₁₆ H _n Cl ₂ N ₅ O: 359.0.

Step 9: Synthesis of Example 39 and Intermediates H1-H4.

General synthesis method C:

Corresponding intermediate G (1 mmol, 1 eq.), Pd(PPh ₃ ) ₄ (29.2 mg, 0.025 mmol, 0.05 eq.) and the corresponding pinacol boronic acid ester (RBpin, 1.1 mmol, 1.0 eq.) 1 eq.) was loaded into an oven-dried μW reactor. The pW reactor was hermetically sealed with a partition and purged with an Ar atmosphere (3 Ar/vacuum cycles). Anhydrous was added. THF (1.9 ml, 0.27M) and the mixture was stirred until completely dissolved. Na ₂ CO ₃ solution (2M, 0.75 ml, 3 eq.) was added and the reaction mixture was reacted under microwave irradiation at 100°C for 40 min (energy power: 150 W). Complete conversion of intermediate G was confirmed by TLC monitoring (heptane: EtOAc). The crude mixture was transferred to a separatory funnel by adding EtOAc (70 ml). The organic phase was washed with water (3x30 ml) and saturated NaCl solution (1x30 ml), dried over anhydrous Na ₂ SO ₄ and filtered through a layer of Celite® on a filter plate. The solvent was removed under reduced pressure to obtain a crude mixture, which was purified by automated flash chromatography to obtain the corresponding intermediate H1-H4 or the compound of Example 39.

The following compounds were prepared according to the general synthesis method C described above for Example 39 and intermediates H1-H4.

Example 39: 6-chloro-2-(1-methyl-1,2,3,4-tetrahydropyridin-4-yl)-N-(2-(morpholinosulfonyl)ethyl)pyrido[3,4-d]pyrimidin-4 -amine.

- 41 044615

Intermediate G2: 394 mg; RBpin: 1-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-

2-yl)-1,2,3,6-tetrahydropyridine, 250.4 mg. Workup of the crude mixture yielded a mixture of two compounds: the expected cross-coupling product (6-chloro-2-(1-methyl-1,2,3,6-tetrahydropyridin-4-yl)-N(2-(morpholinosulfonyl)ethyl)pyrido[ 3,4-d]pyrimidin-4-amine) and the title compound obtained by isomerization of the parent compound. Automated flash chromatography (EtOAc/DCM/MeOH, title compound eluted 40:40:20% v/v) isolated the title compound as a major product contaminated by cross-coupling byproduct (7.7%); weight: 0.417 g; Yield: 50%; Purity: 90.1% (UHPLC-V); yellow solid; ¹ H-NMR (CDCl3), δ (ppm): 8.84 (s, 1H), 6.16 (t, 1H), 6.03-5.93 (m, 1H), 5.41 (d, 1H), 4.94 (d, 1H), 4.88 (t, 2H), 4.16 (t, 4H), 4.15 (t, 2H), 3.62-3.56 (m, 2H ), 3.44 (s, 3H), 3.34 (dd, 4H), 2.86-2.71 (m, 1H), 2.31 (dt, 1H); LR-MS (ESI+): m/z= 454.0 Da [M+H] ⁺ , calc. for C19H ₂₅ ClN ₆ O ₃ S: 453.0.

Intermediate H1: 6-chloro-2-(1-methyl-1,2,3,6-tetrahydropyridin-4-yl)-N-(thiophen-2ylmethyl)pyrido[3,4-d]pyrimidin-4-amine .

Intermediate G1: 311 mg; RBpin: 1-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan2-yl)-1,2,3,6-tetrahydropyridine, 250.4 mg. Automated flash chromatography (EtOAc:MeOH, product elution 97:3% v/v) gave intermediate H1 as a yellow solid; weight: 0.126 g; Yield: 30%; Purity: 89.1% (UHPLC-V); ¹ H-NMR (MeOD), δ (ppm): 8.90 (s, 1H), 8.08 (s, 1H), 7.04-7.36 (m, 1H), 7.27 (dd, 1H), 7.13 (dd, 1H), 6.97 (dd, 1H), 5.04 (d, 2H), 3.35-3.28 (m, 2H), 2.92-2.84 (m, 2H), 2.82-2.75 (m, 2H), 2.47 (s, 3H); LR-MS (ESI+): m/z= 372.1 Yes [M+H] ⁺ , calc. for Ci8Hi8C1N5S: 371.1.

Intermediate H2: tert-butyl 4-(6-chloro-4-((thiophen-2-ylmethyl)amino)pyrido[3,4d]pyrimidin-2-yl)-3,6-dihydropyridin-1 (2H)- carboxylate.

Intermediate G1: 311 mg; RBpin: N-Boc-1,2,3,6tetrahydropyridine-4-boronic acid pinacol ester, 174 mg. Automated flash chromatography (heptane:EtOAc, product elution 78:22% v/v) gave intermediate H2 as a yellow solid; weight: 0.185 g; Yield: 79%; Purity: 97.8% (UHPLC-V); ¹ H-NMR (CDC13), δ (ppm): 9.00 (s, 1H), 7.55 (s, 1H), 7.35 br.s, 1H), 7.25 (dd, 1H), 7.09 (dd, 1H), 6.98 (dd, 1H), 6.21 (t, NH), 5.03 (d, 2H), 4.21 (dd, 2H), 3.66 (t , 2H), 2.82 (brt, 2H), 1.50 (s, 9H); LR-MS (ESI+): m/z= 458.1 Yes [M+H] ⁺ , calc. for C ₂₂ H ₂ 4ClN5O ₂ S: 457.1.

Intermediate H3: tert-butyl 4-(6-chloro-4-((2-(N-phenylsulfamoyl)ethyl)amino)pyrido[3,4-d]pyrimidin-2-yl)-3,6-dihydropyridin- 1(2H)-carboxylate.

Intermediate G3: 448 mg; RBpin: N-Boc-1,2,3,6tetrahydropyridine-4-boronic acid pinacol ester, 174 mg. Automated flash chromatography (heptane:EtOAc, product elution 65:35% v/v) gave intermediate H3 as a yellow solid; weight: 0.465 g; Yield: 83%; Purity: 97.3% (UHPLC-V); ¹ H-NMR (CDC13), δ (ppm): 8.87 (s, 1H), 7.56 br s, 1H), 7.44 br s, 1H), 7.33-7.12 ( m, 5H), 6.82 (t, NH), 4.14 (lat, 4H), 3.61 (lat,

- 42 044615

4H), 2.70 (brt, 2H), 1.50 (s, 9H); LR-MS (ESI+): m/z= 545.2 Da [M+H] ⁺ , calc. for C25H29CMO4S: 544.2.

Intermediate H4: tert-butyl 4-(6-chloro-4-((2-(N-methyl-N-phenylsulfamoyl)ethyl)amino)pyrido[3,4-d]pyrimidin-2-yl)-3, 6-dihydropyridine-1 (2H)-carboxylate.

Intermediate G4: tetrahydropyridine-4-boronic acid,

422 mg; RBpin: pinacol ester N-Boc-1,2,3,6174 mg. Automated flash chromatography (heptane:EtOAc, product elution 70:30% v/v) gave intermediate H4 as a yellow solid; weight: 0.442 g; Yield: 79%; Purity: 99.9% (UHPLC-A); 1H-NMR ( _CDCl3 ), δ (ppm): 8.93 (s, 1H), 7.65 7.64-7.09 (m, 6H), 4.17-4.09 (m, 4H) , 3.63 (t, 2H), 3.47 (t, 2H), 3.36 (s, 3H), 2.81-2.67 (m, 2H), 1.51 (s, 9H); LR-MS (ESI+): m/z= 559.2 Da [M+H] ⁺ , calc. for C ₂₆ H ₃₁ ClN ₆ O ₄ S: 558.2.

Stage 10: Synthesis of Examples 40-41.

The following compounds were prepared following the Boc deprotection process described above for Examples 1-38.

Example 40: 6-chloro-2-(1,2,3,6-tetrahydropyridin-4-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimidin4-amine.

Intermediate H2: (233 mg, 0.5 mmol, 1 eq.); MeOH (5 ml, 0.1 M); conc. HCl (0.15 ml, 1.5 mmol, 3 eq.), t: 17 h. Workup of the reaction mixture gave the title compound as a yellow solid; weight: 186 mg; Yield: 99%; Purity: 94.9% (UHPLC-V), mp: 248°C (cleavage); ¹ H-NMR (MeOD), δ (ppm): 8.90 (s, 1H), 7.94 (s, 1H), 7.43 br s, 1H), 7.18 (dd, 1H), 7.07 (dd, 1H), 6.94 (dd, 1H), 4.99 (d, 2H), 3.61 (dd, 2H), 3.09 (t, 2H), 2.76-2 .68 (m, 2H); LR-MS (ESI+): m/z= 359.1 Yes [M+H] ⁺ , calc. for C ₁₇ H ₁₆ ClN ₅ S: 358.0.

Example 41: 2-((6-chloro-2-(1,2,3,6-tetrahydropyridin-4-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-Nphenylethan-1-sulfonamide .

Intermediate H3: (279.7 mg, 0.5 mmol, 1 eq.); MeOH (5 ml, 0.1 M); conc. HCl (0.15 ml, 1.5 mmol, 3 eq.), t: 17 h. Workup of the reaction mixture gave the title compound as a yellow solid; weight: 239 mg; Yield: 98%; Purity: 91.0% (UHPLC-A), mp: 243.0247.3°C; ¹ H-NMR (MeOD), δ (ppm): 9.21 (s, 1H), 8.33 (s, 1H), 7.43-7.39 (m, 1H), 7.33-7, 20 (m, 5H), 7.13-7.06 (m, 1H), 4.26 (t, 2H), 4.11 (dd, 2H), 3.68 (t, 2H), 3.54 (t, 2H), 3.04-2.96 (m, 2H); LR-MS (ESI+): m/z= 445.1 Yes [M+H] ⁺ , calc. for C20H21CMO2S: 444.1.

Stage 11: Synthesis of Examples 42-45.

General recovery method:

NHR

Cl

Etc. 39

H1-H4

NHR

Etc. 42-45

Pd(OH)2 20% w/w on coal, H2 (1 ^a ™) θ'

EtOAc:MeOH 2:1%.v/v (7 mM)

In an oven-dried 250 mL round bottom flask, the appropriate compound (Example 39 or Intermediate H1-H4) (0.5 mmol, 1 eq.) was dissolved in a solvent mixture [EtOAc (46 mL) and MeOH (23 mL, HPLC grade )] in an Ar atmosphere. Pd(OH) ₂ 20% w/w was added. on carbon (70.8 mg, 0.1 mmol, 0.1 eq.) and performed three cycles of H ₂ /vacuum to remove residual gases from the solvents. The reaction mixture was stirred at 22°C under an H ₂ atmosphere. The reaction was monitored by TLC (EtOAc:MeOH) until complete conversion was achieved. The crude reaction mixture was filtered through a layer of Celite® on a filter plate and the solvents were removed under reduced pressure. The residue was purified by automated flash chromatography to give the corresponding compounds (Examples 42-45).

The following compounds were prepared according to the general reduction method described above for Examples 42-45.

Example 42: 6-chloro-2-(1-methylpiperidin-4-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimidin-4amine.

Intermediate H1: 208 mg. Automated reverse phase flash chromatography (water:MeOH, product elution 20:80% v/v) gave the title compound as a yellow solid; weight: 0.132 g; Yield: 65%; Purity: 91.5% (UHPLC-A); ¹ H-NMR (CDCl3), δ (ppm): 9.00 (s, 1H), 7.50 (s, 1H), 7.26 (dd, 1H), 7.09 (dd, 1H), 6 .98 (dd, 1H), 6.02 (t, NH), 5.04 (d, 2H), 3.052.94 (m, 2H), 2.87-2.74 (m, 1H), 2. 34 (s, 3H), 2.17-1.98 (m, 6H); LR-MS (ESI+): m/z= 374.1 Da [M+H] ⁺ , calc. for C18H ₂₀ ClN ₅ S: 373.1.

Example 43: 6-chloro-2-(1-methylpiperidin-4-yl)-N-(2-(morpholinosulfonyl)ethyl)pyrido[3,4d]pyrimidin-4-amine.

Example 39: 252 mg. Automated reverse phase flash chromatography (water:MeOH, product elution 60:40% v/v) gave the title compound as a yellow solid; weight: 0.414 g; Yield: 55%; Purity: 60.4% (UHPLC-A); ¹ H-NMR (CDCl3), δ (ppm): 8.91 (s, 1H), 8.12 (s, 1H), 4.65 (t, 2H), 4.13 (t, 4H), 3 .77 (t, 2H), 3.32 (dd, 4H), 3.06-2.93 (m, 2H), 2.86-2.73 (m, 1H), 2.18-1.96 (m, 6H), 2.43 (s, 3H); LR-MS (ESI+): m/z= 455.0 Da [M+H] ⁺ , calc. for C19H ₂₇ ClN ₆ O ₃ S: 454.1.

Example 44: 6-chloro-2-(piperidin-4-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimidin-4-amine.

Intermediate H2: 189 mg. Automated flash chromatography (heptane:EtOAc, elution 89:11% v/v) gave tert-butyl 4-(6-chloro-4-((thiophen-2-ylmethyl)amino)pyrido[3,4d]pyrimidine -2-yl)piperidine-1-carboxylate as a yellow solid; weight: 205 mg; Yield: 74%; Purity: 82.9% (UHPLC-A); 1H-NMR (CDCl ₃ ), δ (ppm): 9.00 (s, 1H), 7.54 (s, 1H), 7.26 (dd, 1H), 7.09 (dd, 1H), 6 .99 (dd, 1H), 6.19 (t, 1H), 5.04 (d, 2H), 4.22 (dd, 2H), 3.66 (t, 1H), 3.05-2, 76 (m, 3H), 2.10-1.84 (m, 3H), 1.48 (s, 9H); LR-MS (ESI+): m/z= 460.2 Da [M+H]+, calc. for C ₂ 2H26ClN ₅ O ₂ S: 459.1. This compound (205 mg, 0.37 mmol) was reacted according to the Boc deprotection method described above for Examples 1-38 to obtain the title compound as a yellow solid; weight: 92 mg; Yield: 69%; Purity: 100% (UHPLC-A); 1H-NMR (MEOD), δ (ppm): 8.92 (s, 1H), 8.23 (s, 1H), 7.28 (dd, 1H), 7.13 (dd, 1H), 6. 92 (dd, 1H), 5.12 (d, 2H), 3.59-3.40 (m, 4H), 3.31-3.09 (m, 1H), 2.30-2.17 ( m, 1H); LR-MS (ESI+): m/z= 360.1 Da [M+H] ⁺ , calc. for C^H^Cl^S: 359.1

Example 45: 2-((6-chloro-2-(piperidin-4-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N-methyl-Nphenylethan-1-sulfonamide.

Intermediate H4: 280 mg. Automated flash chromatography (heptαn:EtOAc, product elution 10:90% v/v) gave tert-butyl 4-(6-chloro-4-((2-(N-methyl-Nphenylsulfamoyl)ethyl)amino)pyrido [3,4-d]pyrimidin-2-yl)piperidin-1-carboxylate as a yellow solid; weight: 238 mg; Yield: 85%; Purity: 99.0% (UHPLC-A); 1H-NMR (CDCl ₃ ), δ (ppm): 8.96 (s, 1H), 7.54 (s, 1H), 7.38-7.24 (m, 5H), 4.27-4, 04 (m, 4H), 3.41-3.34 (m, 1H), 3.36 (s, 3H), 2.96-2.65 (m, 4H), 2.00-1.63 ( m, 4H), 1.47 (s, 9H); This compound (238 mg, 0.43 mmol) was reacted according to the Boc deprotection method described above for Examples 1-38 to obtain the title compound as a yellow solid; weight: 152 mg; Yield: 75%; Purity: 97.7%

- 44 044615

(UVELC-A); 1H-NMR (MeOD), δ (ppm): 9.14 (s, 1H), 8.37 (s, 1H), 7.57-7.17 (m, 5H), 4.37-4.16 (m, 2H), 3.763.58 (m, 1H), 3.62 (t, 2H), 3.51 (t, 2H), 3.39 (s, 3H), 3.30-3.10 ( m, 2H), 2.54-2.10 (m, 4H); LR-MS (ESI+):

m/z= 461.2 Yes [M+N] ⁺ , calc. for C ₂₁ H ₂₅ ClN ₆ O ₂ S: 460.1.

Stage 12: Synthesis of Examples 46-61.

General synthesis method D.

The general dehalogenation method described in the present invention was adapted from methods extracted from the protocols described on the following websites -PEPPSI™ CATALYST: Website: www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Aldrich/Bulletin/ al_peppsi_activation_guide.pdf (uploaded 2018/07/20) PEPPSI™ activation guide: Website:

https://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Aldrich/Bulletin/al_peppsi_activation_guide.pdf

NHR

PEPPSI™-IP catalyst^ LiCI

R ³ MX ------------------------DME (4-6 mM), 70 °C, overnight ^^^^N^^R ² r3MX : Examples 46-61

MeMgBr, PrMgCI, PrZnBr, IPrZnBr, IPrMgCI, t-BuZnBr, i-BuZnBr

An oven-dried Schlenk flask was loaded with a stirrer, PEPPSI™-IPr (7 mg, 2 mol%) and LiCl (69 mg, 1.6 mmol, 3.2 eq.) under Ar atmosphere and sealed with a septum. DME (0.8 mL, freshly dried over 4A molecular sieves, oven-activated Schlenk flask, heated at 650°C under vacuum (<1 mmHg) immediately before use) was added and the suspension stirred until the PEPPSI-IPr dissolved . After this time, an organohalide compound (RX, 0.5 mmol, 1 eq.) was added and the mixture was stirred until RX was completely dissolved. In some cases, additional DME 0.2-0.4 ml was necessary to dissolve RX. After obtaining a homogeneous solution, the organometallic compound (R3MX, 0.8 mmol, 1.6 eq.) was added dropwise through a syringe under Ar atmosphere. The reaction mixture turned orange-brown in color, indicating efficient activation of the catalyst. The septum was replaced with a glass screw cap under an Ar atmosphere and stirred at 70°C for 18 hours. The reaction mixture was allowed to cool to 22°C and 10 ml of saturated NH ₄ Cl solution was added. The reaction mixture was stirred at this temperature for 5 min to quench unreacted organometallic (R3MX) species. The mixture was transferred to a separatory funnel with 80 ml EtOAc and 20 ml saturated NH ₄ Cl solution. The phases were separated and the organic phase was washed with water (2x20 ml) and saturated NaCl solution (1x20 ml). The organic phase was dried over anhydrous Na ₂ SO ₄ and filtered through a pad of Celite®. Volatiles were removed under reduced pressure to give a yellow oil, which was purified using an automated flash column (EtOAc:MeOH) to give the corresponding product (Examples 46-61).

The following compounds were prepared in accordance with the general method of synthesis D described above for examples 46-61.

Example 46: 6-methyl-2-(4-methylpiperazin-1-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimidin-4amine.

RX: 6-chloro-2-(4-methylpiperazin-1-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimidin-4-amine (Example 3), 187 mg; R3MX: methylmagnesium bromide (3M in Et ₂ O), 0.27 ml, 0.8 mmol, 1.6 eq.; Automated flash chromatography (EtOAc:MeOH, product elution 93:7% v/v) gave the title compound as a yellow solid; weight: 0.104 g; Yield: 56%; Purity: 96.7% (UHPLC-A), yellow solid; mp: 214.0-217.0°C; 1H-NMR ( _CDCl3 ), δ (ppm): 8.80 (s, 1H), 7.22 (dd, 1H), 7.14 (s, 1H), 7.04 (d, 1H), 6 .95 (dd, 1H), 6.36 (t, NH), 4.94 (d, 2H), 3.97 (t, 4H), 2.51 (s, 3H), 2.50 (t, 4H), 2.35 (s, 3H); LR-MS (ESI+): m/z= 355.1 Yes [M+H] ⁺ , calc. for C ₁₈ H ₂₂ N ₆ S: 354.1.

Example 47: N-(furan-2-ylmethyl)-6-methyl-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4amine.

- 45 044615

RX: 6-chloro-N-(furan-2-ylmethyl)-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-amine (example 4), 179 mg; R3MX: methylmagnesium bromide (3M in Et ₂ O), 0.27 ml, 0.8 mmol, 1.6 eq.; Automated flash chromatography (EtOAc:MeOH, product elution 95:5% v/v) gave the title compound as a yellow solid; weight: 0.080 g; Yield: 45%; Purity: 92.5% (FRESH); ¹ H-NMR (CDCl3), δ (ppm): 8.80 (s, 1H), 7.39 (dd, 1H), 7.011 (s, 1H), 6.36 (dd, 1H), 6.31 (dd, 1H), 5.97 (t, NH), 4.77 (d, 2H), 3.95 (t, 4H), 3.42 (s, 3H), 2.50 (t, 4H) , 2.35 (s, 3H); LR-MS (ESI+): m/z= 339.1 Yes [M+H] ⁺ , calc. for C ₁₆ H ₂₂ N ₆ O: 338.1.

Example 48: 6-methyl-2-(4-methylpiperazin-1-yl)-N-(2-(thiophen-2-yl)ethyl)pyrido[3,4-d]pyrimidin-4 amine.

RX: 6-chloro-2-(4-methylpiperazin-1-yl)-N-(2-(thiophen-2-yl)ethyl)pyrido[3,4-d]pyrimidin-4-amine (Example 6), 194 mg; R3MX: methylmagnesium bromide (3M in Et ₂ O), 0.27 ml, 0.8 mmol, 1.6 eq.; Automated flash chromatography (EtOAc:MeOH, product elution 97:3% v/v) gave the title compound as a yellow solid; weight: 0.161 g; Yield: 82%; Purity: 97.2% (UHPLC-A), yellow solid; mp: 171.1-176.6°C; ¹ H-NMR (CDCl3), δ (ppm): 8.80 (s, 1H), 7.19 (dd, 1H), 7.03 (s, 1H), 6.98 (dd, 1H), 6 .86 (d, 1H), 5.92 (dd, NH), 3.95 (t, 4H), 3.86 (dd, 2H), 3.23 (t, 2H), 2.55 (s, 3H), 2.50 (t, 4H), 2.35 (s, 3H); LR-MS (ESI+): m/z= 369.1 Yes [M+H] ⁺ , calc. for C19H ₂₄ N ₆ S: 368.1.

Example 49: 2-(4-methylpiperazin-1-yl)-6-propyl-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimidin-4 amine.

RX: 6-chloro-2-(4-methylpiperazin-1-yl)-X-(thiophen-2-ylmethyl)pyrido[3,4-pyrimidin-4amine (example 3), 187 mg; R3MX: n-propylzinc bromide (0.5M in THF), 1.6 ml, 0.8 mmol, 1.6 eq.; Automated flash chromatography (EtOAc:MeOH, product elution 95:5% v/v) gave the title compound as a yellow solid; weight: 0.185 g; Yield: 97%; Purity: 95.1% (UHPLC-A); mp: 54.4-62.3°C; ¹ H-NMR (CDCl3), δ (ppm): 8.83 (s, 1H), 7.24 (dd, 1H), 7.09 (s, 1H), 7.05 (d, 1H), 6 .97 (dd, 1H), 6.17 (t, NH), 4.95 (d, 2H), 3.99 (t, 4H), 2.75 (t, 2H), 2.54 (t, 4H), 2.37 (s, 3H), 1.79-1.66 (m, 2H), 0.92 (t, 3H); LR-MS (ESI+): m/z= 383.2 Da [M+H] ⁺ , calc. for C2oH ₂₆ N ₆ S: 382.2.

Example 50: 2-(4-methylpiperazin-1-yl)-6-propyl-N-(2-(thiophen-2-yl)ethyl)pyrido[3,4-d]pyrimidin4-amine.

O G

NH _Λ 1

Ν /А A ζν Ν Ν ι kA

RX: 6-chloro-2-(4-methylpiperazin-1-yl)-N-(2-(thiophen-2-yl)ethyl)pyrido[3,4-d]pyrimidin-4-amine (example 6), 194 mg; R ³ MX: n-propylmagnesium chloride (2M in Et2O), 0.4 ml, 0.8 mmol, 1.6 eq.; Automated flash chromatography (EtOAc:MeOH, product elution 90:10% v/v) gave the title compound as a yellow oil; weight: 0.023 g; Yield: 12%; Purity: 95.4% (UHPLC-A); ¹ H-NMR (CDCl3), δ (ppm): 8.83 (s, 1H), 7.20 (dd, 1H), 6.98 (s, 1H), 6.98 (d, 1H), 6 .87 (d, 1H), 5.78 (t, NH), 3.96 (t, 4H), 3.87 (dd, 2H), 3.24 (t, 2H), 2.77 (t, 2H), 2.51 (t, 4H), 2.36 (s, 3H), 1.79-1.71 (m, 2H), 0.95 (t, 3H); LR-MS (ESI+): m/z= 397.2 Da [M+H] ⁺ , calc. for C ₂₁ H ₂₈ N ₆ S: 396.2.

Example 51: N-(furan-2-ylmethyl)-6-isopropyl-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin4-amine.

RX: 6-chloro-N-(furan-2-ylmethyl)-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-amine (example 4), 179 mg; R3MX: iso-propylzinc chloride (1M in MeTHF), 0.8 mL, 0.8 mmol, 1.6 eq.; Automated flash chromatography (EtOAc:MeOH, product elution 97:3% v/v) gave the title compound as a yellow solid; weight: 0.030 g; Yield: 13%; Purity: 95.4% (UHPLC-A); ¹ H-NMR (CDCl ₃ ), δ (ppm): 8.85 (s, 1H), 7.41 (dd, 1H), 7.06 (s, 1H), 6.37 (dd, 1H), 6.33 (dd, 1H),

5.83 (t, NH), 4.79 (d, 2H), 3.96 (t, 4H), 3.09 (sept, 1H), 2.51 (t, 4H), 2.36 (s , 3H), 1.32 (d, 6H); LR-MS (ESI+): m/z= 367.2 Da [M+H] ⁺ , calc. for C ₂₀ H ₂₆ N ₆ O: 366.2.

Example 52: 6-isopronyl-2-(4-methylniperazin-1-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4d]pyrimidin-4-amine.

RX: 6-chloro-2-(4-methylpiperazin-1-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimidin-4amine (Example 3), 187 mg; R3MX: iso-propylzinc bromide (0.5M in THF), 1.6 ml, 0.8 mmol, 1.6 eq.; Automated flash chromatography (EtOAc:MeOH, eluting product with EtOAc 100% v/v) gave the title compound as a yellow solid; weight: 0.177 g; Yield: 93%; Purity: 96.4% (UHPLC-A); ¹ H-NMR (CDCl3), δ (ppm): 8.84 (s, 1H), 7.22 (dd, 1H), 7.15 (s, 1H), 7.04 (d, 1H), 6 .95 (dd, 1H), 6.47 (t, NH), 4.95 (d, 2H), 3.98 (t, 4H), 3.05 (sept, 1H), 2.50 (t, 4H), 2.34 (s, 3H), 1.27 (d, 6H); LRMS (ESI+): m/z= 383.1 Da [M+H] ⁺ , calc. for C2oH26N ₆ S: 382.2.

Example 53: 6-isopropyl-2-(4-methylpiperazin-1-yl)-N-(2-(thiophen-2-yl)ethyl)pyrido[3,4d]nirimidin-4-amine.

from ²

I NH

ΛΫΐ

Ν<·Ν ^Λ νΑ

RX: 6-chloro-2-(4-methylpiperazin-1-yl)-N-(2-(thiophen-2-yl)ethyl)pyrido[3,4-d]pyrimidin-4-amine (example 6), 194 mg; R ³ MX: iso-propylzinc bromide (0.5M in THF), 1.6 ml, 0.8 mmol, 1.6 eq.; Automated flash chromatography (EtOAc:MeOH, eluting product with EtOAc 100% v/v) gave the title compound as a yellow oil; weight: 0.164 g; Yield: 79%; Purity: 95.0% (UHPLC-A); 1H-NMR (CDCl3), δ (ppm): 8.83 (s, 1H), 7.18 (dd, 1H), 7.12 (s, 1H), 6.97 (dd, 1H), 6. 86 (d, 1H), 6.36 (t, NH), 3.97 (t, 4H), 3.85 (dd, 2H), 3.06 (sept, 1H), 2.53 (t, 4H ), 2.35 (s, 3H), 1.28 (d, 6H); LR-MS (ESI+): m/z= 397.1 Yes [M+H] ⁺ , calc. for C21H ₂₈ N ₆ S: 396.2.

Example 54: 2-((6-isopropyl-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-Nphenylethan-1-sulfonamide.

QN, NH% ^Ph

Yeah?

N

RX: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N-phenylethan-1sulfonamide (Example 16), 231 mg ; R3MX: iso-propylzinc bromide (0.5M in THF), 1.6 ml, 0.8 mmol, 1.6 eq.; Automated flash chromatography (EtOAc:MeOH, product elution 95:5% v/v) gave the title compound as a yellow oil; weight: 0.131 g; Yield: 68%; Purity: 95.7% (UHPLC-A); 1H-NMR (CDCl3), δ (ppm): 8.79 (s, 1H), 7.14 (s, 1H), 7.21-7.07 (m, 5H), 6.74 (t, NH ), 4.03 (dd, 2H), 3.84 (t, 4H), 3.54 (t, 2H), 3.05 (sept, 1H), 2.49 (t, 4H), 2.35 (s, 3H), 1.27 (d, 6H); LR-MS (ESI+): m/z= 470.2 Da [M+H] ⁺ , calc. for C ₂₃ H ₃₁ N ₇ O ₂ S: 469.2.

Example 55: 2-((6-isopropyl-2-(4-methylπpiperazin-1-yl)pyrido[3,4-d]πpyrimidin-4-yl)amino)-Nmethyl-N-phenylethan-1-sulfonamide.

RX: 2-((6-chloro-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-yl)amino)-N-methyl-Nphenylethane-1-sulfonamide (Example 17 ), 238 mg; R3MX: iso-propylzinc bromide (0.5M in THF), 1.6 ml, 0.8 mmol, 1.6 eq.; Automated flash chromatography (EtOAc:MeOH, product elution 95:5% v/v) gave the title compound as a yellow oil; weight: 0.0616 g; Yield: 57%; Purity: 95.8% (UHPLC-A); 1H-NMR ( _CDCl3 ), δ (ppm): 8.84 (s, 1H), 7.37-7.35 (m, 5H), 7.01 (s, 1H), 6.27 (t, NH), 4.09 (dd, 2H), 3.90 (t, 4H), 3.39 (t, 2H), 3.36 (s, 3H), 3.10 (sept, 1H), 2, 50 (t, 4H), 2.37 (s, 3H), 1.32 (d,

- 47 044615

6H); LR-MS (ESI+): m/z= 484.3 Da [M+H] ⁺ , calc. for C24H33N7O2S: 483.2.

Example 56: 6-(tert-butyl)-N-(furan-2-ulmethyl)-2-(4-methylpiperazin-1-yl)pyrido[3,4d]pyrimidin-4-amine.

NH%r°\ f J to ϊΓΎ to ^Ν Ν k^h%

RX: 6-chloro-N-(furan-2-ylmethyl)-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-amine (example 4), 179 mg; R3MX: tert-butylzinc bromide (0.5M in THF), 1.6 mL, 0.8 mmol, 1.6 eq.; Automated flash chromatography (EtOAc:MeOH, eluting product with EtOAc 100% v/v) gave the title compound as a yellow oil; weight: 0.036 g; Yield: 16%; Purity: 85.5% (UHPLC-A); ¹ H-NMR (CDCl3), δ (ppm): 8.14 (d, 1H), 7.39 (dd, 1H), 7.12 (d, 1H), 6.35 (dd, 1H), 6 .30 (dd, 1H), 5.79 (t, NH), 4.76 (d, 2H), 3.96 (t, 4H), 2.50 (t, 4H), 2.36 (s, 3H), 1.61 (with 9H); LR-MS (ESI+): m/z= 381.2 Da [M+H] ⁺ , calc. for C ₂₁ H ₂₈ N ₆ O: 380.2.

Example 57: 6-(tert-butyl)-2-(4-methylpiperazin-1-yl)-N-(thiophene-2-ulmethyl)pyrido[3,4d]pyrimidin-4-amine.

RX: 6-chloro-2-(4-methylpiperazin-1-yl)-N-(thiophene-2-ylmethyl)pyrido[3,4-d]pyrimidin-4amine (example 3), 187 mg; R3MX: tert-butylzinc bromide (0.5M in THF), 1.6 mL, 0.8 mmol, 1.6 eq.; Automated flash chromatography (EtOAc:MeOH, eluting product with EtOAc 100% v/v) gave the title compound as a brown oil; weight: 0.006 g; Yield: 2%; Purity: 74% (UHPLC-A); ¹ H-NMR (CDCl3), δ (ppm): 8.14 (d, 1H), 7.24 (dd, 1H), 7.09 (d, 1H), 7.07 (d, 1H), 6 .98 (dd, 1H), 5.82 (t, NH), 4.95 (d, 2H), 4.00 (t, 4H), 2.54 (t, 4H), 2.37 (s, 3H), 1.61 (with 9H); LR-MS (ESI+): m/z= 397.3 Da [M+H] ⁺ , calc. for C ₂₁ H ₂₈ N ₆ S: 396.2.

Example 58: N-(furan-2-ylmethyl)-6-isobutyl-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4amine.

RX: 6-chloro-N-(furan-2-ylmethyl)-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrumidin-4-amine (example 4), 179 mg; R3MX: iso-butylzinc bromide (0.5M in THF), 1.6 mL, 0.8 mmol, 1.6 eq.; Automated flash chromatography (EtOAc:MeOH, product elution 94:6% v/v) gave the title compound as a brown oil; weight: 0.089 g; Yield: 35%; Purity: 90.7% (UHPLC-A); ¹ H-NMR (CDCl3), δ (ppm): 8.77 (s, 1H), 7.33 (dd, 1H), 6.98 (s, 1H), 6.29 (dd, 1H), 6 .25 (dd, 1H), 5.88 (t, NH), 4.70 (d, 2H), 3.89 (t, 4H), 2.58 (d, 2H), 2.45 (t, 4H), 2.29 (s, 3H), 2.04 (m, 1H), 0.83 (d, 6H); LR-MS (ESI+): m/z= 381.2 Da [M+H] ⁺ , calc. for C2iH28N6O: 380.2.

Example 59: 6-u-isobutyl-2-(4-methylpiperazin-1-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimudin4-amine.

RX: 6-chloro-2-(4-methylpiperazin-1-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimidin-4amine (example 3), 187 mg; R3MX: iso-butylzinc bromide (0.5M in THF), 1.6 mL, 0.8 mmol, 1.6 eq.; Automated flash chromatography (EtOAc:MeOH, product elution 95:05% v/v) gave the title compound as a yellow oil; weight: 0.0198 g; Yield: 9%; Purity: 88.1% (FRESH); 1H-NMR ( _CDCl3 ), δ (ppm): 8.85 (s, 1H), 7.26 (dd, 1H), 7.09 (s, 1H), 7.01-6.98 (m, 2H), 5.84 (t, NH), 4.97 (d, 2H), 3.98 (t, 4H), 2.65 (d, 2H), 2.50 (t, 4H), 2. 35 (s, 3H), 2.17-2.06 (m, 1H), 0.91 (d, 6H); LR-MS (ESI+): m/z= 397.3 Da [M+H] ⁺ , calc. for C2iH28N ₆ S: 396.2.

Example 60: 6-methyl-2-(piperazin-1-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrumidin-4-amine.

τΎvn ΝχΛ.Α,,ΖΧ Ν Ν > k,NH

The compound was prepared by the reaction of 6-chloro-2-(piperazin-1-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4H]pyrimidin-4-amine (example 24) (0.414 g, 1 mmol, 1 equiv.) with di-tert-butyl dicarbonate (241 mg, 1.1 mmol, 1.1 equiv.) in tert-butanol (0.7 ml, 0.7 M) at 50°C for 16 hours. After this time, the mixture was diluted with 50 ml of dichloromethane and the organic phase was washed with hot water (6x20 ml). The organic phase was dried over anhydrous Na ₂ SO ₄ and the volatiles were removed under reduced pressure to give tert-butyl 4-(6-chloro-4-((thiophen-2-ylmethyl)amino)pyrido[3,4-d]pyrimidin- 2yl)piperazine-1-carboxylate as a yellow solid; weight: 0.404 g; Yield: 78%; Purity: 89% (UHPLC-A). The product thus obtained was used without further purification as reagent RX in the general synthesis method D; RX: tert-butyl 4-(6-chloro-4-((thiophen-2ylmethyl)amino)pyrido[3,4-d]pyrimidin-2-yl)piperazine-1-carboxylate, 231 mg; R3MX: methylmagnesium bromide (3M in Et ₂ O), 0.27 ml, 0.8 mmol, 1.6 eq.; Workup of the reaction mixture gave tert-butyl 4-(6methyl-4-((thiophen-2-ylmethyl)amino)pyrido[3,4-d]pyrimidin-2-yl)piperazine-1-carboxylate with a high purity of 87% (UHPLC -A). The product thus obtained, without further purification, was reacted according to the Boc deprotection method described above for Examples 1 to 38 to obtain the title compound as a yellow solid; weight: 0.148 g; Yield: 82.0%; Purity: 88.2% (UHPLC-A); ¹ H-NMR (MeOD), δ (ppm): 8.62 (s, 1H), 7.62 (s, 1H), 7.26 (dd, 1H), 7.09 (d, 1H), 6 .96 (dd, 1H), 4.93 (d, 2H), 4.0 (t, 4H), 3.01 (t, 4H), 2.57 (t, 3H); LR-MS (ESI+): m/z= 341.1 Yes [M+H] ⁺ , calc. for C ₁₇ H ₂₀ N ₆ S: 340.2.

Example 61: 2-(piperazin-1-yl)-6-propyl-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimidin-4-amine.

The compound was prepared by reacting 6-chloro-2-(niperazin-1-yl)-N-(thiophen-2ylmethyl)pyrido[3,4-d]pyrimidin-4-amine (Example 24) (0.414 g, 1 mmol, 1 eq. .) di-tert-butyl dicarbonate (241 mg, 1.1 mmol, 1.1 eq.) in tert-butanol (0.7 ml, 0.7 M) at 50°C for 16 hours. After this time, the mixture was diluted with 50 ml dichloromethane and the organic phase was washed with hot water (6x20 ml). The organic phase was dried over anhydrous Na ₂ SO ₄ and the volatiles were removed under reduced pressure to give tert-butyl 4-(6-chloro-4-((thiophen-2-ylmethyl)amino)pyrido[3,4d]pyrimidin-2- yl)piperazine-1-carboxylate as a yellow solid; weight: 0.329 g; Yield: 65%; Purity: 91% (UHPLC-A). The product thus obtained was used without further purification as reagent RX in the general synthesis method D; RX: tert-butyl 4-(6-chloro-4-((thiophen-2ylmethyl)amino)pyrido[3,4-d]pyrimidin-2-yl)piperazine-1-carboxylate, 232 mg; R3MX: n-propylzinc bromide (0.5M in THF), 1.6 ml, 0.8 mmol, 1.6 eq.; Automated flash chromatography (eluting product with 100% v/v EtOAc) gave tert-butyl 4-(6-propyl-4-((thiophen-2ylmethyl)amino)pyrido[3,4-d]pyrimidin-2- yl)piperazine-1-carboxylate as a yellow solid; weight: 0.087 g; Yield: 36%; Purity: 96.3% (UHPLC-A); ¹ H-NMR (CDCl3), δ (ppm): 8.84 (s, IH), 7.24 (dd, 1H), 7.09 (s, 1H), 7.07 (d, 1H), 6 .97 (t, 1H), 6.13 (t, NH), 4.96 (d, 2H), 3.93 (t, 4H), 3.52 (t, 4H), 2.76 (t, 2H), 1.80-1.68 (m, 2H), 1.50 (s, 9H), 0.93 (t, 3H); LR-MS (ESI+): m/z= 469.3 Da [M+H] ⁺ , calc. for C24H ₃₂ N ₆ O ₂ S: 468.2.

Tert-butyl 4-(6-propyl-4-((thiophen-2-ylmethyl)amino)nirido[3,4-d]pyrimidin-2-yl)niperazine-1carboxylate (87 mg, 0.18 mmol) was reacted according to the Boc deprotection method described above for Examples 1-38 to obtain the title compound as a yellow solid; weight: 0.068 g; Yield: 95.0%; Purity: 91.5% (UHPLC-A); mp: 70.1-81.6°C; ¹ H-NMR (MeOD), δ (ppm): 8.64 (d, IH), 7.61 (d, 1H), 7.25 (ddd, 1H), 7.08 (dd, 1H), 6 .94 (dd, 1H), 4.92 (d, 2H), 3.92 (t, 4H), 2.89 (t, 4H), 2.78 (t, 2H), 1.83-1, 71 (m, 2H), 0.98 (t, 3H); 1H-NMR (CDCl3), δ (ppm): 8.83 (s, 1H), 7.25 (t, 1H), 7.08 (s, 1H), 7.07 (d, 1H), 6. 97 (t, 1H), 6.10 (t, NH), 4.95 (d, 2H), 3.98 (t, 4H), 3.01 (t, 4H), 2.76 (t, 2H ), 2.50 (t, NH), 1.80-1.68 (m, 2H), 0.93 (t, 3H); LR-MS (ESI+): m/z= 369.1 Yes [M+H] ⁺ , calc. for C ₁₉ H ₂₄ N ₆ S: 368.2.

Step 13: Synthesis of Examples 62-67.

General dehalogenation method.

The general dehalogenation method described in the present invention was adapted from a method published by Jang et al., Tet. Lett. 2006, 47, 8917-8920.

NHR _M pi Г Pd/C, ( ^1a ™) A, ^U ϊΐ^Ί N ------------------------------- -“ fl J У

N m X EtOAc:MeOH 2:1% o6/vol (7 mM) N^A..A_ ₂ R ^{2 NR}

Etc. 3, 4, 6, 18, 42, 43 Ave. 62-67

In an oven-dried 250 mL round bottom flask, the appropriate compound (Example 3, 4, 6, 18, 42, or 43) (0.5 mmol, 1 eq.) was dissolved in a solvent mixture [EtOAc (46 mL) and MeOH (23 ml, HPLC quality)] in an Ar atmosphere. Pd/C 10% w/w was added. (26 mg, 0.025 mmol, 0.05 eq.) and performed three cycles of H ₂ /vacuum to remove residual gases from the solvents. The reaction mixture was stirred at 22°C under an H ₂ atmosphere. The progress of the reaction was monitored using TLC

- 49 044615 (EtOAc:MeOH 90:10%v/v). When complete conversion was achieved (1-3 days), the reaction mixture was filtered through a Celite® pad on a filter plate and the solvents were removed under reduced pressure to give a yellow oil, which was purified by automated flash chromatography (EtOAc:MeOH) to give examples (62- 67).

The following compounds were prepared according to the general dehalogenation method described above for Examples 62-67.

Example 62: 2-(4-methylpiperazin-1-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimidin-4-αmin.

Example 3 (187 mg, 0.5 mmol, 1 eq.). Automated flash chromatography (EtOAc:MeOH, product elution 90:10% v/v) gave the title compound as a yellow solid; weight: 113 mg; Yield: 60%; Purity: 90.2% (UHPLC-A); ¹ H-NMR (CDCl ₃ ), δ (ppm): 8.86 (s, 1H), 8.18 (d, 1H), 7.26 (d, 1H), 7.24 (dd, 1H), 7.06 (d, 1H), 6.97 (dd, 1H), 6.18 (t, NH), 4.94 (d, 2H), 4.0 (t, 4H), 2.54 (t , 3H), 2.37 (s, 3H); LR-MS (ESI+): m/z= 341.2 Da [M+H] ⁺ , calc. for C^NS 340.2.

Example 63: N-(furan-2-ylmethyl)-2-(4-methylpiperazin-1-yl)pyrido[3,4-d]pyrimidin-4-amine.

Example 4 (179 mg, 0.5 mmol, 1 eq.). Automated flash chromatography (EtOAc:MeOH, product elution 90:10% v/v) gave the title compound as a yellow solid; weight: 129 mg; Yield: 67%; Purity: 83.9% (UHPLC-A); ¹ H-NMR (CDCl3), δ (ppm): 8.86 (s, 1H), 7.20 (d, 1H), 7.39 (dd, 1H), 7.29 (t, 1H), 6 .34 (dt, 2H), 6.03 (t, NH), 4.78 (d, 2H), 3.99 (t, 4H), 2.53 (t, 4H), 2.38 (s, 3H); LR-MS (ESI+): m/z= 325.1 Da [M+H] ⁺ , calc. for Ci7H2oN ₆ O: 324.1.

Example 64: 2-(4-methylpiperazin-1-yl)-N-(2-(thiophen-2-yl)ethyl)pyrido[3,4-d]pyrimidin-4-amine.

HN

Example 6 (194 mg, 0.5 mmol, 1 eq.). Automated flash chromatography (EtOAc:MeOH, product elution 90:10% v/v) gave the title compound as a yellow solid; weight: 111.2 mg; Yield: 62%; Purity: 98.8% (UHPLC-A); ¹ H-NMR (CDCl3), δ (ppm): 8.86 (s, 1H), 8.19 (d, 1H), 7.20 (dd, 1H), 7.14 (d, 1H), 6 .98 (dd, 1H), 6.87 (dd, 1H), 5.75 (t, NH), 3.98 (t, 4H), 3.88 (q, 2H), 3.24 (t, 2H), 2.52 (t, 4H), 2.37 (s, 3H); LR-MS (ESI+): m/z= 355.1 Yes [M+H] ⁺ , calc. for C18H ₂₂ N ₆ S: 354.2.

Example 65: 2-(4-methylpiperazin-1-yl)-N-(2-(morpholinosulfonyl)ethyl)pyrido[3,4-d]pyrimidin4-amine.

o o

Example 18 (228 mg, 0.5 mmol, 1 eq.). Automated flash chromatography (EtOAc:MeOH, product elution 80:20% v/v) gave the title compound as a yellow solid; weight: 160 mg; Yield: 72%; Purity: 94.6% (UHPLC-A); ¹ H-NMR (CDCl3), δ (ppm): 8.71 (s, 1H), 8.17 (d, 1H), 7.73 (dd, 1H), 4.04 (dd, 2H), 3 .98 (t, 4H), 3.73 (dd, 4H), 3.45 (dd, 2H), 3.27 (dd, 4H), 2.55 (t, 4H), 2.37 (s, 3H); LR-MS (ESI+): m/z= 422.1 Yes [M+H] ⁺ , calc. for C18H ₂₇ N ₇ O ₃ S: 421.2.

Example 66: 2-(1-methylpiperidin-4-yl)-N-(thiophen-2-ylmethyl)pyrido[3,4-d]pyrimidin-4-amine.

Example 42 (187 mg, 0.5 mmol, 1 eq.). Automated reverse phase flash chromatography (water/MeOH, product elution 70:30% v/v) gave the title compound as a yellow solid; weight: 124 mg; Yield: 68%; Purity: 93.2% (UHPLC-A); ¹ H-NMR (CDCl ₃ ), δ

- 50 044615 (ppm): 9.21 (s, 1H), 8.55 (d, 1H), 7.46 (d, 1H), 7.25 (dd, 1H), 7.11 (dd, 1H ), 6.98 (dd, 1H), 6.22 (t, NH), 5.05 (d, 2H), 3.26-3.14 (m, 2H), 3.02-2.88 ( m, 1H), 2.51 (s, 3H), 2.40-2.14 (m, 6H); LR-MS (ESI+): m/z= 340.2 Yes

[M+N] ⁺ , calc. for C ₁₈ H ₂₀ N ₅ S: 339.5.

Example 67: 2-(1-methylpiperidin-4-yl)-N-(2-(morpholinosulfonyl)ethyl)pyrido[3,4-d]pyrimidin4-amine.

o %ΝΜβ

Example 43 (227 mg, 0.5 mmol, 1 eq.). Automated reverse phase flash chromatography (water/MeOH, product elution 70:30% v/v) gave the title compound as a yellow solid; weight: 0.181 g; Yield: 25%; Purity: 58% (UHPLC-A); ¹ H-NMR (CDCl ₃ ), δ (ppm): 9.10 (s, 1H), 8.58 (d, 1H), 7.99 (d, 1H), 4.65 (t, 2H), 4.13 (t, 4H), 3.77 (t, 2H), 3.33 (dd, 4H), 3.06-2.98 (m, 2H), 2.95-2.81 (m, 1H), 2.41 (s, 3H), 2.38-2.14 (m, 6H); LR-MS (ESI+): m/z= 421.1 Yes [M+H] ⁺ , calc. for C19H28N6O3S: 420.1.

Biological analyses.

_H4 binding assay.

Materials.

JNJ7777120, imetite, thioperamide, histamine and chemical reagents such as Tris-HCl and EDTA were supplied by Sigma-Aldrich, VUF10947 was synthesized by FAES FARMA (Lamiako-Leioa, Spain), JNJ10191584 was purchased from Tocris Bioscience, Multiscreen Microplates (MSFBN6B50) were purchased Ali from Merck Millipore, scintillation fluid (Microscint 20), human H ₄ membranes (ES-393-M400UA) and ³ H-histamine (NET 732) were supplied by PerkinElmer.

Ways.

Affinity for the histamine H4 receptor was determined using an H4 binding assay:

Membranes from Cho-Κι cells transfected with the human _H4 receptor and microplates of 96-well format were used.

For competition studies, cell membranes were homogenized in Tris-HCl 50 mM, EDTA 5 mM, pH 7.4 and added to the microplate at a concentration of approximately 15 μg/well. Membrane suspensions were incubated with test compounds for 15 min at 25°C, and the binding reaction was initiated by adding the specific radioligand H ₄ [ ³ H] histamine at a final concentration of 5-8 nM (K _D = 11.1 nM; B _max = 4. 13 pmol/mg protein). Nonspecific binding was determined using 10 μM unlabeled histamine, and the total incubation volume was 275 μl per well.

Incubation was carried out with gentle stirring at 25°C for 60 min and completed by rapid vacuum filtration using pre-impregnated filters (0.5% polyethylenimine). After ten quick washes with cold wash buffer (50 mM Tris-HCl buffer), the filter plates were dried at room temperature for 30 min.

Finally, scintillation liquid (Microscint 20) was added to the entire microplate to measure the radioactivity retained on the filters using a dedicated scintillation counter (Top Count-NXT). Curve analysis and IC ₅₀ values were determined using Graph Pad Prism (GraphPad Software, San Diego, USA).

Test compounds were initially assessed at a single concentration (1 μM) and then, if a significant bias was observed (>40%), a concentration-effect curve was generated. Each test concentration was measured in triplicate.

JNJ7777120, JNJ10191584, imethite, thioperamide and VUF-10497 were used as reference compounds.

Hi binding assay.

Materials.

Cetirizine and pyrilamine were supplied by Sigma-Aldrich, bilastine was synthesized at FAES FARMA (Lamiako-Leioa, Spain), chemical reagents such as Na2HPO4, KH2PO4 or polyvinylpyrrolidone, and multiscreen microplates (MSFBN6B50) were purchased from Merck Millipore, scintillation liquid (Microscint 20 ), human H, membranes (ES-390-M400UA) and ³ H-pyrylamine (NET 594) were supplied by PerkinElmer.

Ways.

Affinity for the histamine III receptor was determined using a Hi binding assay.

Membranes from CHO-K1 cells transfected with the human Hi-receptor and microplates of 96-well format were used.

For competition studies, cell membranes were homogenized in 50 mM phosphate buffer (Na ₂ HPO ₄ and KH2PO4 mixed to pH 7.4 at 25°C) and added to the microplate at a concentration of approximately 5 μg/well. Membrane suspensions were incubated with test compounds for 15 min at 25°C, and the binding reaction was initiated by adding a specific radioligand

- 51 044615

Hi[ ^3H ]pyrylamine at a final concentration of 0.75 nM (KD=1.9 nM; _Bmax =16.1 pmol/mg protein). Nonspecific binding was determined using 10 μM unlabeled pyrilamine, and the total incubation volume was 275 μl per well.

Incubation was carried out with gentle stirring at 25°C for 60 min and completed by rapid vacuum filtration using pre-impregnated filters (5% polyvinylpyrrolidone). After ten quick washes with cold wash buffer (50 mM phosphate buffer), the filter plates were dried at room temperature for 30 min.

Finally, scintillation liquid (Microscint 20) was added to the entire microplate to measure the radioactivity retained on the filters using a dedicated scintillation counter (Top Count-NXT). Curve analysis and IC ₅₀ values were determined using Graph Pad Prism (GraphPad Software, San Diego, USA).

Test compounds were initially assessed at a single concentration (1 μM) and then, if a significant bias was observed (>40%), a concentration-effect curve was generated. Each test concentration was measured in triplicate.

Pyrilamine, cetirizine and bilastine were used as reference compounds.

Table 1

Histamine _H4 and Hi receptor affinity for the compounds of the invention

Example Structure ACTIVITY CLASS hH ₄ R ACTIVITY CLASS hHiR 3 O % CZ 0 O / A IN

- 52 044615

4 / /—2 ° ^l / \ y o Α Β 5 O MO 0 2_' and / Β Β 6 / __ /^ ^z ω-χ -ζ.—/ y o Β - 7 oh I LA / Β _ 8 / Ύ.Ρ V o Β - 14 O A L / ( 2 Ο=ω-Ο ζ^ ΙΖ / \ Α - 15 (/ΖΤ/ζ ο-Άο ς Μ ο Α - 16 Α / ^ζχ /^ ^ζ OW=O ) Μ ο Α -

- 53 044615

17 0 ΗΝ^-Ν'™ ^c vrS kA. A IN 18 О v HN^b ^С1 ^н A - 22 ΗΝ^'·^''· ^α ν0ϊ IN - 24 0 0% ο A IN 25 ο I ¹ xs Ο ο X IN V 26 ο 00 ρ h A - 27 Ph <010 HN^b ^c, V0v 0,ΝΗ A - 28 O it ^r ^ ^r > 0 ¹ Q A -

- 54 044615

37 Ph %NH ^ci Y^On 00 A - 38 %-V HN~> ₀ ^С, ^н 0 A - 41 o /\ ' Ό 0 e- A - 46 τΎ> ^N '^ _n ^ _n -^s Ok IN - 49 7 0 O / IN IN 50 0 O / IN - 51 r ό IN - 52 I TIj kGuk A -

- 55 044615

53 +. 0 C / V - 54 h JI, NH^ ^{Ph N} '^ _N ^ _N ^ A IN 60 YV^N ⁿ '^n ^<< _n -0 0ΝΗ IN IN 68 About Hz s g / IN IN 69 ^ν ^· _ν ^ _ν ^ o. V V 70 P n N αγγ^ ’Άν, Μκ V - 71 Ν ό V ο A - 72 C'^p ^Η %0 ΗΝ-~% CIyPn ^N ArSp A V

- 56 044615

73 hn^q HN^% UK A - 74 O A. A IN 75 O to Z /)-Z I 0 4¾ IN - 76 XkV C° V O A - 77 F ₃ CO 0 HN X) HN^b ^c Wn n^SAm^ IN - 78 0 P <9 ¢7 ¹ A -

- 57 044615

79 0 V O A - 80 MeO 0 ™ 0 HN^'b ^C Wn A - 81 MeS 0 ^H V ΗΝ^ 'b ^Ν ·^Ν ^Α Ν^ Uk A - 82 oh I G A - 83 o k k* % 0 o<P / o IN -

- 58 044615

84 O A - 86 ύ ABOUT A - 87 d O I > 7^ O IN - 88 ί A - 90 η Η / %Ν N ΗΝ'^' % |JN Wn Λ IN - 93 Ω %d A IN 94 o J- ^x %d 0 ok ' d A IN 95 About Sh o 'b A V 98 0 ΗΝ'^0'Ν' Cl _Λ 1 Η ^C YVN Mk IN -

Activity class range:

A: Ki <100 nM

B: Ki<1000 nM

Finally, the histamine _H4 receptor affinity of the compound in Example 3 was compared with the corresponding quinazoline 3Q and pyrido[4,3-d]pyrimidine isomer 3P by binding studies with re-

Claims (13)

H ₄ receptor using the same protocol as described above. The Ki values, % inhibition and IC50 are shown in Table. 2. table 2 Histamine _H4 receptor affinity for reference compounds Compound Ki (nM) % ING. 1C ₅₀ (nM) ν Ave. 3 0.75 94 1.74 ΗΝ^^< ³ \ ΎΎχ 3Q 7.6 - - ϊ Ν ^Χ Ν 7 1 ϊ Cl Ν Ν 3Ρ 339.8 68 889 As shown above, the compounds of formula (I) of the invention provide improved affinity for the human H ₄ -histamine receptor compared to the corresponding quinazoline and isomeric compounds. CLAIM 1. Compound of formula (I') Where R ¹ is selected from hydrogen; halogen; C1-6alkyl, optionally substituted with halogen, C1-6alkyl, C1-6haloalkyl, -N(Ra)(Rb), -ORc or -SRd; where Ra, Rb, Rc and Rd are independently selected from hydrogen, C1-6alkyl, C1-6haloalkyl, C6-10aryl and (C6-10)aryl(C1-6)alkyl; OR ⁴ ; SR ⁴ ; NR4R ⁵ ; where R ⁴ and R ⁵ are independently selected from H and C 1-6 alkyl, optionally substituted with halogen, C _1-6 alkyl, C _1-6 haloalkyl, -N(Ra)(R _b ), -ORc or -SR _d ; X is selected from -O- and -NH-; R ² selected from: With _1-6 alkyl, optionally substituted: _C3-7 cycloalkyl, optionally substituted with halogen, _C1-6 alkyl, _C6-1oaryl or ( _C6-10 )aryl( _C1-6 )alkyl, With _6-10 aryl, optionally substituted with halogen, With _1-6 alkyl, With _6-10 aryl or (C _6-10 )aryl(C _1-6 )alkyl, 5-10 membered heterocyclyl, optionally substituted with halogen, C _1-6 alkyl, C _6-10 aryl or (C _6-10 )aryl(C _1-6 )alkyl, 5-10 membered heteroaryl, optionally substituted with halogen, C _1-6 alkyl, C _3-7 cycloalkyl, C _6-10 aryl or (C _6-10 )aryl(C _1-6 )alkyl, 5-10 membered heterocyclyl , 5-10 membered heteroaryl, -N(R _a )(R _b ), -OR _c or -SR _d ; SOR ¹³ , where R ¹³ is selected from C _1-6 alkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, 5-10 membered heterocyclyl and 510 membered heteroaryl, optionally substituted with C _1-6 alkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl, halogen, -N(R _a )(R _b ), -ORc or -SR _d ; SO2R ¹⁴ , where R ¹⁴ is selected from C _1-6 alkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 ) alkyl, 5-10 membered heterocyclyl and - 60 044615 5-10 membered heteroaryl, optionally substituted with C _1- balkyl, Cb.1oaryl, (Cb _-1 o)aryl(C _1- b)alkyl, halogen, -N(R _a )(R _b ), -ORc or - SRd; SO2NR15R ¹⁶ , where R ¹⁵ and R ¹⁶ are independently selected from H and _{C1_b} alkyl, C3_7cycloalkyl _{, Cb_10 aryl, (Cb. 10 ) aryl ( C1 . b} )alkyl, 5-10-membered heterocyclyl and 5-10-membered heteroaryl, optionally substituted with _{C1_b alkyl, C1_b haloalkyl, C6_10 aryl, (Cb. 10 ) aryl ( C1.b )} alkyl, 5-10-membered heterocyclyl, _5-10 -membered heteroaryl, halogen, -N(R _a )(R _b ), -ORc or -SRd; And SO(=NH)NHR ¹⁷ , where R ¹⁷ is selected from H and C1_ _b alkyl, C ₃ _ ₇ cycloalkyl, C _b _ ₁₀ aryl, (C _{b 10} )aryl(C _{1 b} )alkyl, 5-10- membered heterocyclyl and 5-10-membered heteroaryl, optionally substituted with C1_ _b alkyl, C ₁ - _b haloalkyl, C _b - ₁₀ aryl, (C _b . ₁₀ )aryl(C ₁ . _b ) alkyl, 5-10 membered heterocyclyl, 5-10 membered heteroaryl, halogen, -N(R _a )(R _b ), -OR _c or -SRd; C _3-7 cycloalkyl, optionally substituted with halogen, C ₁ - _b alkyl, C _b _ ₁₀ aryl or (C _{b 10} )aryl(C _{1 b} ) alkyl; C _b - ₁₀ aryl, optionally substituted with halogen, C ₁ - _b alkyl, C _b _ ₁₀ aryl or (C _{b 10} )aryl(C _{1 b} )alkyl; and (C _b . ₁₀ )aryl(C ₁ . _b )alkyl, optionally substituted with halogen, C 1_ _b alkyl, C 1_ _b haloalkyl, C _b _ ₁₀ aryl or (C _b . ₁₀ )aryl(C ₁ . _b )alkyl; R ³ selected from: 5-10 membered heterocyclyl, optionally substituted with halogen, C1_ _b alkyl, C1_ _b haloalkyl, -N(R _a )(R _b ), -ORc, -SRd, -C(O)R _e , -C(O)OR _f , -C(O)N(R _g )(R _h ) or -OC(O)Rj; where R _e , Rf, Rg, R _h and Rj are independently selected from hydrogen, _{C1_b} alkyl, _{C1_b} haloalkyl, _{Cb_10} aryl and ( _{Cb 10} )aryl(C ₁ . _b ) _alkyl , and NR18R ¹⁹ , where R ¹⁸ is selected from H and C1-balkyl, and ^R19 is selected from _C1-6 alkyl, optionally substituted with 5-10 membered heterocyclyl, optionally substituted with _C1-6 alkyl, or 5-10 membered heteroaryl _, optionally substituted C1-balkyl; and wherein the terms 5-10 membered heterocyclyl and 5-10 membered heteroaryl refer to rings that consist of carbon atoms and 1 to 4 heteroatoms selected from nitrogen, oxygen and sulfur; with the proviso that the compound of formula (I') is not (4-fluorobenzyl)-(2-piperidin-1ylpyrido[3,4-th]pyrimidin-4-yl)amine; [2-(3,4-dihydro-1H-isoquinolin-2-yl)pyrido[3,4-th]pyrimidin4-yl]pyridin-4-ylmethylamine. 2. A compound according to claim 1, where R ¹ is selected from hydrogen, halogen and C1_ _b alkyl. 3. The connection according to any one of claims 1, 2, where R ² is selected from: C1-balkyl, optionally substituted: With _3-7 cycloalkyl, optionally substituted with halogen or C ₁ - _b alkyl, With _b - ₁₀ aryl, optionally substituted with halogen or C ₁ - _b alkyl, 5-10 membered heterocyclyl, optionally substituted with halogen or C ₁ - _b alkyl, 5-10-membered heteroaryl, optionally substituted with halogen or C ₁ - _b alkyl, SOR ¹³ , where R ¹³ is selected from C ₁ - _b alkyl, C _b - ₁₀ aryl and (C _{b 10} )aryl(C ₁ . _b )alkyl, optionally substituted with halogen, C 1_ _b alkyl, C _b _ ₁₀ aryl or ( _{With b.10} )aryl( _C1.b )alkyl _; SO2R ¹⁴ , where R ¹⁴ is selected from _{C1_b alkyl , Cb_10} aryl _{and (Cb_10)aryl(C1.b)alkyl, optionally substituted with halogen, C1_b alkyl , Cb_10 aryl or} ( _{Cb 10} )aryl( _C1b ) _alkyl ; SO2NR15R ¹⁶ , where R ¹⁵ and R ¹⁶ are independently selected from H and C ₁ _ _b alkyl, _C _ ₁₀ aryl, (C ₁ . ₁₀ )aryl(C ₁ . _b ) alkyl and 5-10 membered heteroaryl, optionally substituted C1_ _b alkyl, C1_ _b haloalkyl, C ₆ _ ₁₀ aryl, (C _{b 10} )aryl(C ₁ . _b ) alkyl, 5-10 membered heteroaryl, halogen, -N(R _a )(R _b ), - OR _c or -SRd, where R _a , R _b , Rc and Rd are independently selected from hydrogen, C ₁ - _b alkyl, C ₁ - _b haloalkyl, C ₆ - ₁₀ aryl and (C _b . ₁₀ )aryl(C ₁ . _b )alkyl; And SO(=NH)NHR ¹⁷ , where R ¹⁷ is selected from H and C ₁ - _b alkyl, C ₆ - ₁₀ aryl, (C _{b 10} )aryl(C _{1 b} ) alkyl and 5-10 membered heteroaryl, optionally substituted with C ₁ - _b alkyl, C ₁ - _b haloalkyl, C ₆ _ ₁₀ aryl, (C _{b 10} )aryl(C ₁ . _b ) alkyl, 5-10 membered heteroaryl, halogen, -N(R _a )(R _b ), -OR _c or -SRd; C _3-7 cycloalkyl, optionally substituted with halogen or C ₁ - _b alkyl; C ₆ - ₁₀ aryl, optionally substituted with halogen or C1_ _b alkyl; and ( _Cb . ₁₀ )aryl( _C1.b )alkyl, optionally substituted with halogen or _{C1_b} alkyl _. 4. The connection according to any one of claims 1-3, where R ² is selected from: With _1-3 alkyl, optionally substituted: With _3-7 cycloalkyl, With _{6_10 aryl} , optionally substituted with halogen or C1_ _b alkyl, 5-10 membered heteroaryl, optionally substituted with halogen or C ₁ - _b alkyl; SOR ¹³ , where R ¹³ is selected from C ₁ - _b alkyl, C ₆ - ₁₀ aryl and (C _{b 10} )aryl(C ₁ . _b )alkyl, optionally substituted with C 1 -balkyl or halogen; SO2R ¹⁴ , where R ¹⁴ is selected from C ₁ - _b alkyl, C ₆ - ₁₀ aryl, (C 1 . _{b )} aryl(C ₁ . _b ) alkyl and 5-10 membered heterocyclyl, optionally substituted with C ₁ - _b alkyl or halogen; SO2NR15R ¹⁶ , where R ¹⁵ and R ¹⁶ are independently selected from H and C ₁ - _b alkyl, C ₆ - ₁₀ aryl, (C _b . ₁₀ ) aryl (C ₁ . _b ) alkyl and 5-10 membered heteroaryl, optionally substituted C1_ _b alkyl, C1_ _b haloalkyl, C ₆ _ ₁₀ aryl, 5-10-membered heteroaryl, halogen, -N(R _a )(R _b ), -OR _c or -SR _d , where R _a , R _b , R _c and R _d are independently selected from hydrogen, C _1-6 alkyl and C _1-6 haloalkyl; And SO(=NH)NHR ¹⁷ , where R ¹⁷ is selected from H and C _1-6 alkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl and 5-10 membered heteroaryl, optionally substituted with C _1-6 alkyl, C _1-6 haloalkyl, C _6-10 aryl, 5-10 membered heteroaryl, halogen, -N(R _a )(R _b ), -ORc or -SRd; C _3-7 cycloalkyl, optionally substituted with halogen or C _1-6 alkyl; C _6-10 aryl, optionally substituted with halogen or C _1-6 alkyl; and (C _6-10 )aryl(C _1-3 )alkyl, optionally substituted with halogen or C _1-6 alkyl. 5. A compound according to any one of claims 1 to 4, where XR ² represents a group of the formula -NH-(CH ₂ ) _n SO ₂ NR ¹⁵ R ¹⁶ , where: n selected from 1, 2 and 3; R ¹⁵ is selected from H and C _1-6 alkyl, optionally substituted by -N(R _a )(Rb) or -ORc, where Ra, Rb and R _c are independently selected from hydrogen and C _1-6 alkyl; R ¹⁶ is selected from C _1-6 alkyl, C _6-10 aryl, (C _6-10 )aryl(C _1-6 )alkyl and 5-10 membered heteroaryl, optionally substituted with C _1-6 alkyl, C _1-6 haloalkyl, C _6-10 aryl, 5-10 membered heteroaryl, halogen, -N(R _a )(R _b ), -ORc, or -SRd, where Ra, R _b , Rc and Rd are independently selected from hydrogen, C _1-6 alkyl and C _1-6 haloalkyl. 6. A compound according to any one of claims 1 to 4, where XR ² represents a group of the formula -NH-(CH ₂ )nZ, where: n selected from 1, 2 and 3; Z is selected from 5- or 6-membered heterocyclyl and 5- or 6-membered heteroaryl, optionally substituted with halogen or C _1-6 alkyl. 7. A compound according to any one of claims 1 to 6, where R ³ is selected from: 5-10 membered heterocyclyl, optionally substituted with C _1-6 alkyl or -N(R _a )(R _b ), where Ra and R _b are independently selected from hydrogen and C _1-6 alkyl; And -NR7R ⁸ wherein R ⁷ is H and R ⁸ is C _1-6 alkyl, optionally substituted with 5-10 membered heterocyclyl, optionally substituted with C _1-6 alkyl. 8. A compound according to any one of claims 1 to 7, where R ³ is an N-containing 5-10 membered heterocyclyl, optionally substituted with C _1-6 alkyl or -N(R _a )(Rb), where Ra and Rb are independently selected from hydrogen and C _1-6 alkyl. 9. A compound according to any one of claims 1 to 8, wherein the compound of formula (I') is selected from: - 62 044615 - 63 044615 - 64 044615 - 65 044615 - 66 044615 o o o 10. Use of the compound of formula (I) (I) where R ¹ is selected from hydrogen; halogen; C1-6alkyl, optionally substituted with halogen, C1-6alkyl, C1-6haloalkyl, -N(Ra)(Rb), -ORc or -SRd; where Ra, Rb, Rc and Rd are independently selected from hydrogen, C1-6alkyl, C1.6haloalkyl, C6.10aryl and (C6.10)aryl(C1.6)alkyl; OR ⁴ ; SR ⁴ ; NR ⁴ _R ⁵ where R ⁴ and R ⁵ are independently selected from H and _{C1_6} alkyl, optionally substituted with halogen, _{C1_6} alkyl, _{C1_6} haloalkyl, -N( _Ra )(Rb), -ORc or -SRd ; X is selected from -O- and -NH-; R ² selected from: C ₁ . ₆ alkyl, optionally substituted: C ₁ _ ₆ alkyl, C3.7cycloalkyl, _{optionally substituted} with halogen, _{C1_6alkyl , C6_10aryl} or ( _{C6_10} ) _aryl ( _{C1_6} )alkyl, From ₆ . ₁₀ aryl, optionally substituted with halogen, C ₁ _ ₆ alkyl, C ₆ _ ₁₀ aryl or (C ₆ - ₁₀ )aryl(C ₁ . ₆ ) alkyl, - 67 044615 5-10 membered heterocyclyl, optionally substituted with halogen, Ci-balkyl, Cb-yuaryl or (Cb-1o)aryl(C1.b)alkyl, 5-10 membered heteroaryl, optionally substituted with halogen, C^alkyl, C ₃ . ₇ cycloalkyl, C ₆ yuaryl, (Cb-u)aryl(C1.b)alkyl, 5-10 membered heterocyclyl, 5-10 membered heteroaryl, -N(R _a )(R _b ), -OR _C or _-SRd ; SOR ¹³ , where R ¹³ is selected from C^alkyl, _C6.yuaryl , (Cb-1)aryl(C1.b)alkyl, 5-10-membered heterocyclyl and 510-membered heteroaryl, optionally substituted with C^alkyl, _C6 .yuaryl, (Cb-u)aryl(C1.b)alkyl, halogen, -N(R _a )(R _b ), -OR _C or -SR _d ; SO2R ¹⁴ , where R ¹⁴ is selected from C^alkyl, Cb-yuaryl, (Cb-u)aryl(C1.b)alkyl, 5-10 membered heterocyclyl and 5-10 membered heteroaryl, optionally substituted with Ci-balkyl, Cb -yuaryl, (Cb-u)aryl(C1.b)alkyl, halogen, -N(R _a )(R _b ), -ORc or -SR _d ; SO2NR ¹⁵ R ¹⁶ , where R ¹⁵ and R ¹⁶ are independently selected from H, Scvalkil, C ₃ . ₇ cycloalkyl, Cb-yuaryl, (Cb-1o)aryl(C1-b)alkyl, 5-10-membered heterocyclyl and 5-10-membered heteroaryl, optionally substituted with Ci-balkyl, Ci-bhaloalkyl, Cb-yuaryl, (Cb-yuaryl -ω)aryl(C1.b)alkyl, 5-10 membered heterocyclyl, 5-10 membered heteroaryl, halogen, -N(R _a )(R _b ), -ORc or -SR _d ; And SO(=NH)NHR ¹⁷ , where R ¹⁷ is selected from H and C^alkyl, C ₃ . ₇ cycloalkyl, Cb-yuaryl, ( _C6.iu )aryl(C1^)alkyl, 510-membered heterocyclyl and 5-10-membered heteroaryl, optionally substituted with C^alkyl, Ci-bhalogenalkyl, Cb-yuaryl or (Cb-uaryl )aryl(C1.b)alkyl, 5-10 membered heterocyclyl, 5-10 membered heteroaryl, halogen, -N(R _a )(R _b ), -ORc or -SR _d ; C ₃ . ₇ cycloalkyl, optionally substituted with halogen, C^alkyl, Cb-yuaryl or (Cb-1 o)aryl(C1_b)alkyl; Sb-yuaryl, optionally substituted with halogen, Scvalkyl, Sb-yuaryl or (Sb-u)aryl(C1.b)alkyl; and (Cb-o)aryl(C1-b)alkyl, optionally substituted with halogen, Scvalkyl, Ci-bhaloalkyl, Cb-yuaryl or (Cb-o)aryl(C1-b)alkyl; R ³ selected from: 5-10 membered heterocyclyl, optionally substituted with halogen, C^alkyl, C^haloalkyl, -N(Ra)(Rb), -ORc, -SR _d , -C(O)Re, -C(O)OR _f , -C(O)N(Rg)(R _h ) or -OC(O)R,; where Re, _Rf , _Rg , _Rh and R are independently selected from hydrogen, C^alkyl, C^haloalkyl, Cb-yuaryl and (Cb-u)aryl(C1.b)alkyl, and NR ¹⁸ R ¹⁹ , where R ¹⁸ is selected from H and C1.6 alkyl, and R ¹⁹ is selected from C1.6 alkyl, optionally substituted with 5-10 membered heterocyclyl, optionally substituted with C^alkyl, or 5-10 membered heteroaryl, optionally substituted Scvalkilom; and wherein the terms 5-10 membered heterocyclyl and 5-10 membered heteroaryl refer to rings that consist of carbon atoms and 1 to 4 heteroatoms selected from nitrogen, oxygen and sulfur; with the proviso that the compound of formula (I) is not [2-(3,4-dihydro-1H-isoquinolin-2yl)pyrido[3,4-4]pyrimidin-4-yl]pyridin-4-ylmethylamine; for the prevention or treatment of an H4 receptor mediated condition selected from inflammatory diseases; allergic diseases; dermatological diseases; autoimmune diseases; pruritic disorders, lymphatic disorders, immunodeficiency diseases, respiratory diseases, heart diseases, kidney diseases, pain disorders, overactive bladder conditions, vestibular disorders, joint diseases and degenerative macular diseases. 11. Use according to claim 10, wherein the inflammatory diseases are selected from inflammatory skin diseases, inflammatory diseases of the gastrointestinal tract and inflammatory diseases of the eyes. 12. Use according to claim 10, where the condition is selected from allergy, asthma, dry eye, conjunctivitis, uveitis, allergic rhinitis, rhinoconjuntivitis, chronic obstructive airways disease (COPD), atopic dermatitis, psoriasis, pruritus, uremic pruritus, urticaria, rheumatoid arthritis, psoriatic arthritis, colitis, Crohn's disease and ulcerative colitis, myocardial ischemia, diabetic nephropathy, inflammatory pain, neuropathic pain, dizziness, tinnitus, atherosclerosis, multiple sclerosis, mastocytosis and inflammatory or systemic lupus erythematosus. 13. Application according to any one of paragraphs. 10-12, where the compound of formula (I) is not (4-fluorobenzyl)-(2piperidin-1-ylpyrido[3,4-4]pyrimidin-4-yl)amine. ^gj) Eurasian Patent Organization, EAPO Russia, 109012, Moscow, Maly Cherkassky lane, 2