SG172181A1 - Derivatives of 6-cycloamino-2,3-di-pyridinyl-imidazo[1,2-b]-pyridazine, preparation and therapeutic application thereof - Google Patents

Description

DERIVATIVES OF 6-CYCLOAMINO-2,3-DIPYRIDINYLIMIDAZO[1 2-bJ-PYRIDAZINE ’ PREPARATION AND THERAPEUTIC APPLICATION THEREOF

The present invention relates to 6-cycloamino-2,3-dihydropyridylimidazo[1,2- blpyridazine derivatives, to a process for preparing them and to their therapeutic use, in the treatment or prevention of diseases involving casein kinase 1 epsilon and/or casein kinase 1 delta.

One subject of the present invention is compounds corresponding to the general formula (I)

Ry

RN

- bY ;N N

L—g 7 < Rs oo in which - R; represents a pyridyl group optionally substituted with one or more substituents chosen from halogen atoms and groups Cis-alkyl; - Rs represents a hydrogen atom or a group Ci.z-alkyl; - - A represents a group C,_r-alkylene optionally substituted with one or two groups R,.

T B represents a group Cs.7-alkylene optionally substituted with a group Ry. - L represents either a nitrogen atom optionally substituted with a group R; or Ry, or a carbon atom substituted with a group Re; and a group Ry or two groups Res: the carbon atoms of A and B being optionally substituted with one or more groups Ry, which may be identical to or different from each other;

3 -2-

Ra. Rp and R; are defined such that: two groups R, may together form a group Cy.g-alkylene;

Ra and Ry, may together form a bond or a group Cis-alkylene;

Ra and R; may together form a bond or a group Ci.s-alkylene;

Ry and R; may together form a bond or a group Cis-alkylene;

Raq represents a group chosen from a hydrogen atom and the groups Csg-alkyl, C3.s- cycloalkyl, Cs.7-cycloalkyl-Ci.g-alkyl, C1g-alkylthio-C-1¢-alkyl, Cy.s-alkyloxy-C.¢- alkyl, C+.e-fluoroalkyl, benzyl, C.c-acyl and hydroxy-Ci.g-alkyl:

Re1 represents a group -NR4Rs or a cyclic monoamine optionally comprising an oxygen atom, the cyclic monoamine being optionally substituted with one or more substituents chosen from a fluorine atom and the groups Cig-alkyl, Cie alkyloxy and hydroxyl; two groups Re; form, with the carbon atom that bears them, a cyclic monoamine optionally comprising an oxygen atom, this cyclic monoamine being optionally substituted with one or more groups Ry, which may be identical to or different from each other;

Rt represents a group Cigalkyl, Csr-cycloalkyl, Cs r-cycloalkyl-Cig-alkyl, Cis- alkyloxy-C-alkyl, hydroxy-C.¢-alkyl, C1.s-fluoroalkyl or benzyl;

Ry and Rs represent, independently of each other, a hydrogen atom or a group Cig alkyl, Cs7-cycloalkyl or Ca 7-cycloalkyl-C.g-alkyl; - Ry and Rg represent, independently of each other, a hydrogen atom or a group Cy.4- alkyl.

The compounds of formula (I) may comprise one or more asymmetric carbon atoms.

They may thus exist in the form of enantiomers or diastereoisomers. These enantiomers and diasterecisomers, and also mixtures thereof, including racemic mixtures, form part of the invention.

© WO 2010/070238 \ PCT/FR2009/052594 ’ The compounds of formula (I) may exist in the form of bases or of acid-addition salts. - Such addition salts form part of the invention. These salts are advantageously prepared with pharmaceutically acceptable acids, but the salts of other acids that are useful, for example, for purifying or isolating the compounds of formula (I) also form part of the invention.

The compounds of formula (I) may also exist in the form of hydrates or solvates, i.e. in the form of associations or combinations with one or more water molecules or with a solvent. Such hydrates and solvates also form part of the invention.

In the context of the invention, the following definitions apply: - Ctz in which t and z may take values from 1 to 7: a carbon-based chain possibly containing from t to z carbon atoms, for example Cy; is a carbon- based chain that may contain from 1 to 7 carbon atoms; - alkyl: a linear or branched, saturated aliphatic group; for example a group C1¢- alkyl represents a linear or branched carbon-based chain of 1 to 6 carbon atoms, for example a methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl or hexyl; EERE - alkylene: a linear or branched, saturated divalent alkyl group, for example a group Cig-alkylene represents a linear or branched divalent carbon-based chain of 1°to 6 carbon atoms, for example a methylene, ethylene, 1- methylethylene or propylene; Sa - cycloalkyl: a cyclic alkyl group, for example a group Cs.r-cycloalkyl represents a cyclic carbon-based group of 3 to 7 carbon atoms, for example a cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl; - acyl: agroup alkyl-C(O)-; - hydroxyl: a group —OH; - cyclic monoamine: a saturated cyclic carbon-based chain comprising 1 nitrogen atom; - hydroxyalkyl: an alkyl group in which a hydrogen atom has been replaced with a hydroxyl group; - alkyloxy: a group —O-alky!; - alkylthio: a group ~S-alkyl:

- fluoroalkyl: an alkyl group in which one or more hydrogen atoms have been ’ replaced with a fluorine atom; : : 0 - fluoroalkyloxy: an alkyloxy group in which one or more hydrogen atoms have been replaced with a fluorine atom: - a halogen atom: a fluorine, chlorine, bromine or iodine atom; - aryl: a monocyclic or bicyclic aromatic group containing between 6 and 10 carbon atoms. Examples of aryl groups that may be mentioned include phenyl and naphthyl groups.

As non-limiting examples of cyclic amines or diamines formed by N, A, L. and B, mention may be made especially of aziridine, azetidine, pyrrolidine, piperidine, -azepine, morpholine, thiomorpholine, homopiperidine, decahydroquinoline, decahydroisoguinoline, azabicycloheptane, azabicyciooctane, azabicyclononane, azaoxobicycloheptane, azathiabicycloheptane, azaoxobicyclooctane, azathiabicyclooctane; piperazine, homopiperazine, diazacyclooctane, diazacyclononane, diazacyclodecane, diazacycloundecane, octahydropyrrolopyrazine, octahydropymrolodiazepine, octahydropyrrolopyrrole, octahydropyrrolopyridine, decahydronaphthyridine, diazabicycloheptane, diazabicyclooctane, diazabicyclononane, diazaspiroheptane, diazaspirooctane, diazaspirononane, diazaspirodecane, diazaspiroundecane and oxadiazaspiroundecane.

Among the compounds of general formula (1) that are subjects of the invention, a first group of compounds is constituted by compounds for which; -L represents either a nitrogen atom optionally substituted with a group R; or R, or a carbon atom substituted with a group Req and a group Re the other substituents being as defined above.

Among the compounds of general formula (I) that are subjects of the invention, a second group of compounds is constituted by compounds for which: : - R2 represents a pyridyl group, optionally substituted with one or more substituents chosen from fluorine and a methyl group; the other substituents being as defined above. -

Cs

Among the compounds of general formula (I) that are subjects of the invention, a } third group of compounds is constituted by compounds for which: - R3 represents a hydrogen atom or a methyl group; the other substituents being as defined above.

Among the compounds of general formula (I) that are subjects of the invention, a fourth group of compounds is constituted by compounds for which:

R7 and Rg represent a hydrogen atom or a methyl group; the other substituents being as defined above.

Among the compounds that are subjects of the invention, a fifth group of compounds is constituted by compounds for which: ~~ Arepresents a group Cs.r-alkylene optionally substituted with one or two groups R;; - B represents a group C.7-alkylene optionally substituted with a group Ry; -L represents a nitrogen atom optionally substituted with a group R; or Ry; the carbon atoms of A and B being optionally substituted with one or more groups Ry, which may be identical to or different from each other:

Ra, Ry and R; are defined such that: ) two groups R, may together form a group Cs.¢-alkylene;

Ra and Ry, may together form a bond or a group C¢-alkylene;

Ra and R; may together form a bond or a group Cqs-alkylene;

Rb and R. may together form a bond or a group Cyg-alkylene;

Rs represents a group chosen from a hydrogen atom and groups Ci.g-alkyl, Cay cycloalkyl, Ca.r-cycloalkyl-C4s-alkyl, Ci.¢-alkylthio-C1.s-alkyl, Cie-alkyloxy-Cq.6- alkyl, C1.¢-fluoroalkyl, benzyl, C¢-acyl or hydroxy-C.s-alkyl;

Ry represents a group Cig-alkyl, Ca.r-cycloalkyl, Cs.r-cycloalkyl-Cyg-alkyl, Ci.c- alkyloxy-C1.g-alkyl, hydroxy-C1.s-alkyl, Ci.e-fluoroalkyl or benzyl; ~ the other substituents being as defined above. :

. WO 2010/070238 PCT/FR2009/052594 . -6-

Among the compounds of general formula (I) that are subjects of the invention, a sixth group of compounds is constituted by compounds for which: - A represents a group C,z-alkylene optionally substituted with one or two groups R;; - B represents a group Cs.7-alkylene optionally substituted with a group Ry; -L represents a carbon atom substituted with a group Req and a group Rg; the carbon atoms of A and B being optionally substituted with one or more groups Ry, which may be identical to or different from each other:

Ra, Ry and R; are defined such that: two groups Ra may together form a group Ci¢-alkylene;

Ra and Ry, may together form a bond or a group Cis-alkylene;

Ra and R; may together form a bond or a group C.¢-alkylene;

Ry and R; may together form a bond or a group Cy.g-alkylene;

Rq represents a group chosen from a hydrogen atom and groups Ci g-alkyl, Caz7- cycloalkyl, Cs.r-cycloalkyl-C¢-alkyi, Ca.g-alkylthio-Cq.g-alkyl, Cig-alkyloxy-Cq.e- alkyl, Cs¢-fluoroalkyl, benzyl, C1-acyl or hydroxy-Cy.¢-alkyl:

Re represents a group -NR4Rs or a cyclic monoamine optionally comprising an oxygen atom, the cyclic monoamine being optionally substituted with one or more substituents chosen from a fluorine atom and groups Cis-alkyl, Cy.g- alkyloxy or hydroxyl;

Ry represents a group Cie-alkyl, Csy-cycloalkyl, Car-cycloalkyl-Cy.gs-alkyl, Cig ~~ alkyloxy-C..s-alkyl, hydroxy-C.¢-alkyl, C4.s-fluoroalkyl or benzyl;

R4 and Rs represent, independently of each other, a hydrogen atom or a group Ci4- alkyl, Cs7-cycloalkyl or Ca.r-cycloatkyl-Cyg-alkyl: 30 . - the other substituents being as defined above. - :

Among the compounds of general formula (1) that are subjects of the invention, a seventh group of compounds is constituted by compounds for which:

- the cyclic amine formed by -N-A-L-B- represents a piperazinyl or ) hexahydropyrrolopyrrolyl group, optionally substituted with one or more groups Cqg- alkyl; - oo the other substituents being as defined above.

Among the compounds of general formula (1) that are subjects of the invention, an eighth group of compounds is constituted by compounds for which; the cyclic amine formed by -N-A-L-B- represents a pyrrolidinylpiperidyl group; - Rz, Ra, Ry and Rg being as defined above.

Among the compounds of general formula (1) that are subjects of the invention, a "ninth group of compounds is constituted by compounds for which: - the cyclic amine formed by —N-A-L-B- represents a (35)-3-methyipiperazin-1-yl, 3,3- dimethylpiperazin-1-y, 4-isopropyipiperazin-1-yl, piperazin-1-yl, (3R)-3- isopropylpiperazin-1-yl or (cis)-5-methylhexahydropyrrolo[3,4-cJpyrrol-2(1 H)-yl group; the other substituents being as defined above.

Among the compounds of general formula (1) that are subjects of the invention, a tenth group of compounds is constituted by compounds for which: ~~ 20 - the cyclic amine formed by —N-A-L-B- represents a 4-pyrrolidin-1-ylpiperidin-1-yl group, . the other substituents being as defined above.

Among the compounds of general formula (I) that are subjects of the invention, an eleventh group of compounds is constituted by compounds for which: - the cyclic amine formed by —N-A-L-B- represents a (38)-3-methylpiperazin-1 -yl, 3,3- dimethylipiperazin-1-yl, 4-isopropylpiperazin-1-yl, piperazin-1 -yl, (3R)-3- isopropylpiperazin-1-yl, (cis)-5-methythexahydropyrrolo[3,4-c]pyrrol-2(1H)-yl or 4- pyrrolidin-1 -ylpiperidin-1-yl group; - R2 represents a pyridyl group, optionally substituted with one or more substituents chosen from fluorine and a methyl group; =~ Rs represents a hydrogen atom or a methyl group; ~~ Ryand Rg represent a hydrogen atom or a methyl group; in the form of the base or of an acid-addition salt.

Among the compounds that are subjects of the invention, mention may be made especially of: + B6-[(3S)-3-Methylpiperazin-1 -¥il-3~(pyrid-4-yl)-2-(pyrid-3-yl)imidazof1 ,2-b]pyridazine; 6-[(3S)-3-Methylpiperazin-1 -¥1)-3-(2-methylpyrid-4-yl)-2-(pyrid-3-yl)imidazo[1 ,2- blpyridazine; 6-(3,3-Dimethylpiperazin-1 -y1)-3~(pyrid-4-yl}-2-(pyrid-3-yl)imidazo[ 1 .2-blpyridazine; 6-(4-Isopropylpiperazin-1-yl)-3- pyrid-4-yl}-2-(pyrid-3-yl)imidazo[ 1 .2-b)pyridazine: 6-(4-Isopropylpiperazin-1 -yI)-3-(2-methyl pyrid-4-yl)-2-(pyrid-3-yl)imidazo[1,2- blpyridazine; 2-(5-Fluoropyrid-3-y1)-6-[( 3S)-3-methylpiperazin-1 -yl}-3-(pyrid-4-yl)imidazo[1,2- blpyridazine; : 2-(5-Fluoropyrid-3-y1}-6-[(3S)-3-methylpiperazin-1-yl}-3-(2-methylpyrid-4- yhimidazo[1,2-blpyridazine:; 2~(5-Fluoropyrid-3-yl)-6-(4-isopropylpiperazin-1 -yl)-3-(pyrid-4-yl)imidazo[1,2- blpyridazine; 6-(4-Isopropylpiperazin-1 -¥1}-3-(2-methyipyrid-4-yl)-2-(5-methylpyrid-3-yl)imid azo[1,2- blpyridazine: 6-Piperazin-1 -yl-2,3-bis(pyrid-4-yl)imidazo[1 .2-blpyridazine; :

6-[(35)-3-Methylpiperazin-1 -¥I)-3-(2-methylpyrid-4-yl)-2-(pyrid-4-yl)imidazo[1 ,2- blpyridazine; 6-(3,3-Dimethylpiperazin-1 -yl)-2,3-bis(pyrid-4-yl)imidazo[1 .2-b]pyridazine; 6+(3,3-Dimethylpiperazin-1-yl)-3-(2-methylpyrid-4-yl)-2-(pyrid-4-yl)imidazo[1 2- blpyridazine;

6-(3,3-Dimethylpiperazin-1 -yi)-8-methyl-2,3-bis(pyrid-4-yl)imidazo[1 2-blpyridazine: 6-[(3R)-3-Isopropylpiperazin-1 -¥1}-2,3-bis(pyrid-4-yl)imidazo[1 ,2-b]pyridazine: 6-(4-1sopropylpiperazin-1 -y1)-2,3-bis(pyrid-4-yl)imidazo[1 ,2-blpyridazine: 6-(4-Isopropylpiperazin-1 -¥1)-3-(2-methylpyrid-4-yl)-2-(pyrid-4-yl)imidazo[1 2- b]pyridazine: 6-I(cis)-5-Methylhexahydropyrrolo[3,4-clpyrrol-2-yl]-2,3-bis(pyrid-4-ylimidazo[ 1 2- blpyridazine: 2,3-Bis(pyrid-4-yl)-6-(4-pyrrolidin-1 -Ylpiperidin-1-yl)imidazo[1,2-b]pyridazine: 2-(2-Fluoropyrid-4-yl}-6-[( 3S)-3-methylpiperazin-1 -YI}-3-(pyrid-4-yl)imidazo[1,2- blpyridazine;

2-(2-Fluoropyrid-4-yl}-6-[(3S)-3-methylpiperazin-1-yl]-3-(2-methylpyrid-4- } yl)imidazo[1,2-b]pyridazine: 2~(2-Fluoropyrid-4-yl)-6-(4-isopropylpiperazin-1 -yl)-3-(pyrid-4-yl)imidazo[1,2- blpyridazine; 2-(2-Fluoropyrid-4-yl)-6-(4-isopropylpiperazin-1 ~yl)-3-(2-methylpyrid-4-yl)imidazo[1,2- blpyridazine.

In accordance with the invention, the compounds of general formula (I) may be prepared according to the general process described in Scheme 1 below.

SCHEME 1 oo 3 | eb - Rp FN =N rr R

To CT xg” ON | X, (IV) ny " = R,

R, (Ila)

CR A) Cr

RA NN -E I NY Re rr k xn os - a \ NP

ON Rs am

M

In general and as illustrated in Scheme 1, the 6-cycloamino-2,3-di-pyridylimidazo[ 1 ,2- blpyridazine derivatives of general formula (I) in which Ry, Rs, A, L, B, Ry and Rg are : as defined above may be prepared from a 3~(pyrid-4-yl)imidazo[1,2-b]pyridazine derivative of general formula (1), in which Ry, Rs, Ry and Rg are as defined above and

Xe represents a leaving group such as a halogen, by treatment with an amine of general formula (lla) in which A, L and B are as defined previously. This reaction may be performed by heating the reagents in a polar solvent such as pentanol or dimethyl sulfoxide.

The imidazo[1,2-bjpyridazine derivatives of general formula (ll) may be prepared by metal-catalysed coupling between a 3-haloimidazo[1,2-b]pyridazine derivative of general formula (lil), in which Rs, Xe, Ry, and Rg are as defined above and Xs represents a halogen such as bromine or iodine and more particularly iodine, and a pyridine derivative of general formula (Ia) in which R; is as defined above and M represents a trialkylstannyi group, usually a tributylstannyl group or a dihydroxyboryl or dialkyloxyboryl group, usually a 4.,4.5,5-tetramethy!-1,3,3,2-dioxaborolan-2-yi group, under the Stille or Suzuki conditions.

The couplings according to the Stille method are performed, for example, by heating in the presence of a catalyst such as tetrakis(triphenylphosphine)palladium or copper fodide, in a solvent such as N,N-dimethylacetamide.

The couplings according to the Suzuki method are performed, for example, by heating in the presence of a catalyst such as 1,1- bis(diphenylphosphino)ferrocenedichloropalladium and a mineral base such as caesium carbonate, in a solvent mixture such as dioxane and water.

The 3-haloimidazo[1,2-b]pyridazine derivatives of general formula (Nl) are obtained by regioselective bromination or iodination of an imidazo[1,2-b]pyridazine derivative of general formula (IV), in which Raz, Xe, Rr and Rg are as defined above. This ~ reaction may be performed using N-bromo- or iodosuccinimide or iodine monochloride in a polar solvent such as acetonitrile, tetrahydrofuran, methanol or chioroform.

The imidazo[1,2-b]pyridazine derivatives of general formula (IV) are known (Journal of Heterocyclic Chemistry (2002), 39(4), 737-742) or may be prepared by analogy with methods known to those skilled in the art. oo

In a second alternative, according to Scheme 2, the 6-cycloamino-2,3- dipyridylimidazo[1,2-bjpyridazine derivatives of general formula (i) as defined above oe

. Co -11- : -may be prepared in two steps from an imidazo[1,2-blpyridazine derivative of general ) formula (V) in which R,, A, L, B, R7 and Rg are as defined previously. oo

- WO 2010/070238 | PCT/FR2009/052594 . -42- ’ SCHEME 2

Re

R, ZN x _N J R, mi

L—B Vv)

Cdn § = Ry _Alkyl -

N oo y (Va)

Rg R,

Or PN / R, - R

A—N a Nf [1 A—N N (Vil) - \ Rs

JAlkyl

M : Po

Oy wn =N" Rs

Ch (lla) Rg / 0 cl

R, = ~=N « _N / R, 0” cl

AN N Cl

L—B J } — R, (h

I5 According to a first approach, the reattion of an imidazo[1,2-b]pyridazine derivative of general formula (V) with the mixture of a pyridine derivative of general formula (Va) in which Rj is as defined previously, and of an alkyl chloroformate in which the alkyl group represents a Cq¢-alkyl, for example ethyl chloroformate, leads to the derivative of general formula (V1) in which R,, A, L, B, Rs, Ry and Rs are as defined above. The derivative of general formula (V1) is then oxidized using ortho-chloranil in a solvent such as toluene, to give the 6-cycloamino-2,3-bis-pyridylimidazo[1,2-b]pyridazine derivatives of general formula (1).

According to a second approach, a regioselective aromatic bromination or iodination of imidazo[1,2-b]pyridazine derivatives of general formula (V) gives the 3-bromo- or iodoimidazo[1,2-blpyridazine derivatives of general formula (VII) in which R;, A, L, B,

Rz and Rg are as defined above and X; represents a halogen such as bromine or iodine, more particularly iodine. This reaction may be performed using N-bromo- or iodosuccinimide or iodine monochloride in a polar solvent such as acetonitrile, tetrahydrofuran, methanol or chloroform.

The 6-cycloamino-2,3-di-pyridylimidazo[1 ,2-b]pyridazine derivatives of general formula (i) are then prepared by metal-catalysed coupling between these 3-bromo- or iodoimidazo[1,2-b]pyridazine derivatives of general formula (Vil) and a pyridine derivative of general formula (Illa) as defined above, under the Stille or Suzuki conditions.

In a third alteative, according to Scheme 3, the 6-cycloamino-2,3-di- pyridylimidazo[1,2-b]pyridazine derivatives of general formula (I) as defined above may be prepared in three steps from a 2-bromoimidazo[1,2-b]pyridazine derivative of general formula (VIH) in which A, L, B, Ry; and Rg are as defined previously. ~ Regioselective aromatic iodination of imidazo[1,2-b]pyridazine derivatives of general formula (VIII) gives the 2-bromo-3-iodoimidazo[1,2-b]pyridazine derivatives of general formula (IX) in which A, L, B, R; and Re are as defined above. This reaction may be performed using N-iodosuccinimide or iodine monochloride in a polar solvent such as acetonitrile, tetrahydrofuran, methanol or chloroform.

Co :

- WO 2010/070238 : i» PCT/FR2009/052594

SCHEME 3

Re Rg

Can NL uo An Sef or 4 I (VII) (IX) : M

I) (lla) = R,

Ry | | CR To < _N / R, (Xa) A—N XN

A Ld = Rs =N ’ 0 (X)

A first regioselective metal-catalysed coupling reaction between these 2-bromo-3-iodo- imidazo[1,2-blpyridazine of general formula (IX) and a pyridine derivative of general formula (lila) as defined above, under the Stille or Suzuki conditions, leads to the 2- bromoimidazo[1,2-b]pyridazine derivatives of general formula (X) in which A, L, B, Rs, Ry and Rg are as defined above.

Finally, a second metal-catalysed coupling reaction between a 2-bromo-3- iodoimidazo[1,2-b]pyridazine derivative of general formula (X) and a pyridine : derivative of general formula (Xa) in which R; is as defined above and M represents a trialkylstannyl group, usually ja tributylstannyl group or a dihydroxyboryl or dialkyloxyboryl group, usually a 4,4,5,5-tetramethyl-1,3,3,2-dioxaborolan-2-y| group, under the Stile or Suzuki conditions, leads to the 6-cycloamino-2,3-di- pyridylimidazo[1,2-b]pyridazine derivatives of general formula (1) as defined above.

SE

The couplings according to the Stille methods are performed, for example, by heating in the presence of a catalyst such as tetrakis(triphenylphosphine) palladium or copper ~ fodide, in a solvent such as N,N-dimethylacetamide.

Precursors

The 3-pyrid-4-ylimidazo[1,2-b]pyridazine derivatives of general formula (V) as defined above may be prepared by condensation between a pyridazin-3-ylamine derivative of : general formula (XI) in which A, L, B, R; and Rs are as defined above and a 2-bromo, chloro- or iodoethan-1-one derivative of general formula (Xia) in which Rz is as defined above and X represents a bromine, chlorine or iodine atom.

The reaction may be performed by heating the reagents in a polar solvent such as ethanol or butanol.

The pyridazin-3-ylamine derivatives of general formula (XI) are known (Journal of

Medicinal Chemistry (2008), 51(12), 3507-3525) or may be prepared by analogy with methods known to those skilled in the art.

The 3-pyrid-4-ylimidazo[1,2-b]pyridazine derivatives of general formula (V) as defined ~ 20 above may also be prepared via a metal-catalysed coupling reaction between the 2- bromoimidazo[1,2-b]pyridazine derivatives of general formula (VIll) as defined previously and a pyridine derivative of general formula (Xa) as defined above, under the Stille or Suzuki conditions.

The 2-bromoimidazo[1,2-b]pyridazine derivatives of general formula (VI) may be prepared from a 2-bromoimidazo[1,2-blpyridazine derivative of general formula (XII), in which R; and Rg are as defined above and Xs represents a leaving group such as a halogen, more particularly chlorine, by treatment with an amine of general formula (lla) as defined previously. This reaction may be performed by heating the reagents ina polar solvent such as pentanol or dimethyl sulfoxide. “The 2-bromoimidazo[1,2-bjpyridazine derivatives of general formula (XII) are obtained in two steps from a S-halopyridazin-3-ylamine of general formula (XIV) in which Xs represents a leaving group such as a halogen, more particularly chlorine,

and Ry and Rg are as defined previously. Thus, the 5-halopyridazin-3-ylamine ' derivatives of general formula (XI) are alkylated using an alkyl 2-bromo-or 2- chloroacetate, for example ethyl 2-bromoacetate, to give a 6-amino-3-halo-1- (alkyloxycarbonylmethyt)pyridazin-1-ium hydrobromide or hydrochloride of general 5S formula (Xill) for which Xs represents a leaving group such as a halogen, more particularly chlorine, while R; and Rs are as defined previously. The 6-amino-3-halo- ~_ 1-(alkyloxycarbonylmethyl)pyridazin-1-ium hydrobromides or hydrochlorides of general formula (Xlil) are cyclized using phosphorus oxybromide to give the 2-bromo- 3~(pyrid-4-yl)imidazo[1,2-b]pyridazine derivatives of general formula (XII). . 0

Ry OR Rg

R, — | NH, X R, = —=N } : —_— R x UN | N a 2

A—N N A—N N 4 0 4

RM

H (Xa)

A R

Rg LB < 8 (Ila) 7 N :

R, NN = ON Br - NJ) A—N XN J

XT NT BR oo

L—B : (XID) oo (VII)

Br : : Oo

Rs or Re :

Rin NH: Og Ri ANH, _N__ Br -

Xs” ON” 1 ‘ x SN

Et 0” to” (XIV) (XH)

In the text hereinabove, the term “leaving group” means a group that can be readily cleaved from a molecule by breaking a heterolytic bond, with loss of an electron pair.

This group may thus be readily replaced with another group during a substitution ’ reaction, for example. Such leaving groups are, for example, halogens or an activated hydroxyl group such as a mesyl, tosyl, triflate, acetyl, etc. Examples of leaving groups and references for preparing them are given in “Advances in Organic Chemistry”,

J. March, 3" Edition, Wiley Interscience, pp. 310-316.

Protecting groups

For the compounds of general formula (1) or (lla) as defined above and in the case where the group N-A-L-B comprises a primary or secondary amine function, this function may be optionally protected during the synthesis with a protecting group, for example a benzyl or a t-butyloxycarbonyl.

The examples that follow describe the preparation of certain compounds in accordance with the invention. These examples are not limiting, but serve merely to illustrate the invention. The numbers of the illustrated compounds refer to those given in Table 1 hereinbelow, which illustrate the chemical structures and physical properties, respectively, of a number of compounds according to the invention.

Example 1 (compound 13): 6-(3,3-Dimethylpiperazin-1-yl)-3-(2-methylpyrid-4-yi)- 2-(pyrid-4-yl)imidazo[1,2-b]pyridazine

H.C N i _] ’ \ CH : ==N 3

Step 1.1. 6-Chloro-2-(pyrid-4-yl)imidazo[1,2-b]pyridazine

N x N JNJ

Cl N

To a solution of 24.0 g (85.3 mmol) of 3-amino-6-chloropyridazine in 1.5 L of refluxing ethanol are added portionwise 33.2 g (256 mmol) of 2-bromo-1-(pyrid-4-yl)ethanone hydrobromide (CAS 5469-69-2) and then 12.0 ml (85.4 mmol) of triethylamine, } dropwise over 45 minutes. The mixture is refluxed for 3 hours. After cooling, the solvent is evaporated off under reduced pressure and the red-brown residue is taken up in chloroform and 300 ml of 1N sodium hydroxide solution. After stirring for 15 minutes, the mixture is filtered and the solid residue is washed with chloroform. The organic phase is separated out, washed with water and dried over sodium sulfate to give 13 g of a brown solid, after evaporating off the solvent. The residue is purified on a column of 500 g of silica gel, eluting with a mixture of dichloromethane, methanol and aqueous ammonia (97/3/0.3) to give 10.1 g of 6-chloro-2-(pyrid-4-ylYimidazo[1,2- blpyridazine in the form of a dark beige solid, after triturating in diisopropyl ether, : filtering off and drying under reduced pressure. m.p. 203-205°C 'H NMR (DMSO-de) &: 9.15 (s, 1H); 8.70 (d, 2H); 8.30 (d, 1H); 8.0 (d, 2H); 7.45 (d, 1H) ppm. : . Step1.2. = 6-Chloro-3-iodo-2-(pyrid-4-yl)imidazo[1 ,2-blpyridazine

AN =N —

Cl N .

To a solution of 10.4 g (45.1 mmol) of 6-chloro-2-(pyrid-4-yl)imidazo[1,2-b]pyridazine in 1 L of chloroform are added, at room temperature, 21.9 g (135 mmol) of iodine chloride in 100 ml of methanol. After reaction for 24 hours, the mixture is poured into saturated sodium bicarbonate solution and the resulting mixture is decolorized by adding aqueous 5% sodium thiosulfate solution. The organic phase is separated out, dried over sodium sulfate and concentrated under reduced pressure to give 14.4 g of

B-chloro-3-iodo-2-(pyrid-4-yl)imidazo[1,2-b]pyridazine in the form of a beige-coloured solid, containing about 10% of 8-chloro-2-(pyrid-4-yt)imidazo[1 ,2-blpyridazine, after triturating in 200 mi of acetonitrile, filtering off and drying. "HNMR (DMSO-dg) 6: 8.75 (d, 2H); 8.30 (d, 1H); 8.15 (d, 2H); 7.50 (d, 1H) ppm.

Step 1.3. 8-Chloro-3-(2-methylpyrid-4-yl)-2-( pyrid-4-yl)imidazo[1,2-bjpyridazine

NN —

Jon 7 NJ

Cl N 7 \ =v

To a mixture of 2.85 g (6.39 mmol) of 6-chloro-2-(pyrid-4-yl)imidazo[1 .2-blpyridazine, 1.14 g (6.12 mmol} of (2-methyl-4-pyridyl)boronic acid (CAS 579476-63-4) and 6.3 g (19 mmol) of caesium carbonate in 400 ml of a mixture of tetrahydrofuran and water (9/1) is added, after degassing with argon, 0.47 g (0.58 mmol) of 1,1- bis(diphenylphosphino)ferrocenedichloropalladium (Il) (CAS 72287-26-4). The : mixture is stirred at reflux for 18 hours. The mixture is concentrated under reduced pressure and the residue is taken up in chloroform. The organic phase is washed with water and dried over sodium sulfate, and the solvent is evaporated off under reduced pressure. The residue is purified on a column of 110 g of silica gel, eluting with a mixture of dichloromethane, methanol and aqueous ammonia (96/4/0.4) to give 1.35 g of 6-chloro-3-(2-methylpyrid-4-yl)-2-(pyrid-4-yhimidazo[1,2-b]pyridazine in the form of a white powder, after triturating in acetonitrile, filtering off and drying. m.p.: 218-222°C 'H NMR (DMSO-dg) 8: 8.60 (d, 1H); 8.55 (d, 2H); 7.95 (d, 1H); 7.50 (d, 2H); 7.35 (s, 1H), 7.25 (d, 1H); 7.15 (d, 1H); 2.60 (s, 3H) ppm.

Step 1.4. 6-(3,3-Dimethylpiperazin-1 -yl)-3-(2-methylpyrid-4-yi)-2-(pyrid-4- yl)imidazo[1,2-blpyridazine

ZN =N — ~ ng J ) = CH

A mixture of 0.500 g (1.55 mmol) of 6-chloro-3-(2-methylpyrid-4-yl)-2-(pyrid-4- yl)imidazo[1,2-b]pyridazine and 0.52 g (4.7 mmol} of 2,2-dimethylpiperazine in 5 ml of pentanol is refluxed for 24 hours at 150°C. The reaction medium is cooled and poured into aqueous 2N hydrochloric acid solution. The aqueous phase is washed with diethyl ether and then basified with aqueous 2N sodium hydroxide solution, and the product is extracted with chloroform. The organic phase is dried over sodium sulfate and the solvent is evaporated off under reduced pressure. The solid obtained is purified on 35 g of silica gel, eluting with a mixture of dichloromethane, methanol and aqueous ammonia (94/6/0.6) to give 0.17 g of 6-(3,3-dimethylpiperazin-1-yi)-3-(2- methylpyrid-4-yl}-2-(pyrid-4-yl)imidazo[ 1 ,2-blpyridazine in the form of a beige- coloured powder, after dissolving in 10 ml of acetonitrile and crystallizing by addition of diethyl ether, filtering off and drying. m.p.: 185-187°C 'H NMR (CDCl) 8: 8.60 (m, 3H); 7.80 (d, 1H); 7.60 (d, 2H); 7.50 (s, 1H); 7.40 (d, 2H); ~~ 6.95(d, 1H); 3.45 (dd, 2H); 3.30 (s. 2H); 3.10 (dd, 2H); 2.65 (s, 3H); 1.2 (s, 6H) ppm.

Example 2 (compound 14): 6-(3,3-Dimethylpiperazin-1-yl)-8-methy}-2.3- bis(pyrid-4-yllimidazo[1,2-b]pyridazine

CH,

L0G

Ho SN {NJ

HN. 7 =N

Step 2.1. 3-Amino-6-chloro-4-methylpyridazine and 3-amino-6-chioro-5-methyi- pyridazine

CH, rr ot

Co SY a SN

In an autoclave, a suspension of 50.0 g (307 mmol) of 3,6-dichioro-4- methylpyridazine in 170 ml 30% aqueous ammonia is heated at 120°C for 18 hours.

After cooling, the mixture is poured into 200 ml of water and the solid is recovered by filtration. After drying under reduced pressure, the mixture of products is recrystallized from ethyl acetate to give 40 g of a mixture of 3-amino-6-chloro-4- methylpyridazine and 3-amino-6-chloro-5-methylpyridazine (32/68).

'H NMR (CDCl3): 7.15 and 6.75 (s and s, 1H); 5.0 (broad signal, 2H); 2.35 and 2.25 ’ (s and s, 3H). :

Step2.2. 6-Amino-3-chloro-1 -ethoxycarbonylmethyl-5-methylpyridazin-1-ium bromide and 6-amino-3-chloro-1-ethoxycarbonylmethyl-4-methylpyridazin-1-ium bromide

CH,

HC _~ NH, | _ NH,

CI” °N 1 Br cl "1 Br

HC” 0 Oo : He” 0 O

To a solution of 36.0 g (251 mmol) of a mixture of 3-amino-6-chloro-4- methyipyridazine and 3-amino-6-chloro-5-methylpyridazine (32/68) in 350 ml of refluxing ethanol are added portionwise 30.6 ml (275 mmol) of ethyl 2-bromoacetate and heating is continued for 24 hours. After cooling, the reaction medium is partially concentrated under reduced pressure and then diluted with 200 ml of acetone, the suspension is cooled to 0°C and the precipitate is separated out by filtration. The filtrate is then partially concentrated under reduced pressure and diluted with 150 ml of acetone, and the suspension is again cooled to 0°C. The precipitate is separated out by filtration and combined with the first crop. After drying, 29.8 g of a mixture of 6- amino-3-chioro-1-ethoxycarbonylmethyl-4-methylpyridazin-1-ium bromide and 6- amino-3-chloro-1-ethoxycarbonylmethyl-5-methylpyridazin-1-ium bromide (30/70) are obtained in total.

TH NMR (MeOD): 7.90 and 7.55 (s and s, 1H); 5.30 and 5.25 (s and s, 2H); 4.35 (q, 2H); 2.50 and 2.45 (s and s, 3H); 1.35 (t, 3H).

Step 2.3. 2-Bromo-6-chloro/bromo-7-methylimidazo[1,2-b]pyridazine and 2- bromo-6-chloro/bromo-8-methylimidazo[1,2-b]pyridazine :

CH, “rr or ;

Br ) r

Br/CI SI BrCl SN 7

A mixture of 27.8 g (89.5 mmol) of 6-amino-3-chloro-1-ethoxycarbonylmethyl-4- o methylpyridazin-1-ium, 6-amino-3-chloro-1 -ethoxycarbonylmethyl-5-methylpyridazin- 1-ium (30/70) and 82 g (286 mmol) of phosphorus oxybromide in 100 ml of toluene is heated at 160°C for 1 hour in a sealed tube. After cooling, the solid deposited on the walls is detached and the mixture is poured into 500 ml of water at 0°C. The aqueous phase is then basified by addition of aqueous ammonia and, after stirring for 1 hour, the product is dissolved in chloroform. The organic phase is separated out, dried over sodium sulfate and concentrated under reduced pressure to give 22 g of a brown solid. The solid is then purified by chromatography on a column of 450 g of silica gel, eluting with dichloromethane, to give 5.0 g of 2-bromo-6-chloro-8-methylimidazo[1,2- b]pyridazine containing 2,6-dibromo-8-methylimidazo[1,2-b]pyridazine in the form of a white powder (41/59). oo "HNMR (CDCl5): 7.80 (s, 1H); 6.85 and 7.00 (s and s, 1H); 2.55 (s, 3H).

Continuing the elution with a mixture of dichloromethane, methanol and aqueous ammonia (80/10/1) gives 15.2 g of 2-bromo-6-chloro/bromo-7-methylimidazo[1,2- blpyridazine containing 2,6-dibromo-7-methylimidazo[1,2-b]pyridazine, in the form of a pink powder. "HNMR (CDC): 7.95 (s, 1H); 7.75 (s, 1H); 2.55 (s, 3H),

Step 2.4. 2-Bromo-6-(3,3-dimethylpiperazin-1-yl)-8-methylimidazo[1 ,2-

CH, joe 1 Va i blpyridazine

A mixture of 4.95 g (about 20 mmol) of 2-bromo-6-chloro-8-methylimidazo[1,2- blpyridazine containing 2,8-dibromo-8-methylimidazo[1 (#blpyridazine, 25 g (22 mmol) of 2,2-dimethylpiperazine and 2.8 ml of triethylamine in 60 ml of pentanol is heated at 150°C for 3 days in a sealed tube. After cooling, the reaction medium is poured into aqueous 1N hydrochloric acid solution. The aqueous phase is washed with ethyl acetate and then basified with aqueous ammonia solution and the product is extracted with dichloromethane. The organic phase is dried over sodium sulfate oo -23- and the solvent is evaporated off under reduced pressure. The beige-coloured solid obtained is purified on a column of 80 g of silica gel, eluting with a mixture of dichloromethane, methanol and aqueous ammonia (95/65/0.5) to give 4.6 g of 2- bromo-6-(3,3-dimethylpiperazin-1-y1)-8-methylimidazo[1 ,2-blpyridazine in the form of -awhite powder, m.p.: 139-141°C 'H NMR (CDCl3) 8: 7.65 (s, 1H); 7.65 (s, 1H); 3.5 (m, 2H); 3.30 (s, 2H); 3.10 (m, 2H); 2.60 (s, 3H); 1.25 (s, 6H) ppm.

Step 2.5. 6-(3,3-Dimethylpiperazin-1 -yl}-8-methyl-2-(pyrid-4-yl)imidazo[1, 2- blpyridazine : ) CH, a LC oo

LS x TO)

HCY ON N

HN.

To a mixture of 4.64 g (14.3 mmol) of 2-bromo-6-(3,3-dimethylipiperazin-1-yl)-8- methylimidazo[1,2-b]pyridazine and 2.5 g (17 mmol) of (4-pyridyl)boronic acid (CAS 1692-15-5) in 100 ml of a mixture of tetrahydrofuran and water (9/1), are added, after degassing with argon, 14 g (43 mmo!) of caesium carbonate and 1.05 g (1.29 mmol) of a complex of 1,1"-bis(diphenylphosphino)ferrocenedichloropalladium (1) and dichloromethane (PdClx(dppf).CH.Cl,). After stirring for 8 hours at reflux, the reaction medium is poured into aqueous 1N hydrochloric acid solution. The aqueous phase is washed with ethyl acetate and then basified with aqueous ammonia solution and the product is extracted with dichloromethane. The organic phase is dried over sodium sulfate and the solvent is evaporated off under reduced pressure. The black oil obtained is purified by chromatography on a column of 120 g of silica gel, eluting with a mixture of dichloromethane, methanol and aqueous ammonia (95/65/0.5) to give 3.1gof 6-(3,3-dimethylpiperazin-1-yl}-8-methyl-2-(pyrid-4-yl)imidazo[1 ,2-blpyridazine in the form of an oil. : 'H NMR (CDCls) 6: 8.70 (d, 2H); 8.15 (s, 1H); 7.85 (d, 2H); 6.70 (s, 1H); 3.55 (m, 2H); 3.30 (s, 2H); 3.15 (m, 2H); 2.70 (s, 3H); 1.30 (s, 6H) ppm.

Step 2.6. 6-(3,3-Dimethylpiperazin-1-yl)-3-iodo-8-methyl-2-(pyrid-4-ylimidazo[1 ,2- ’ blpyridazine

CH, dnc ey A

HN.

To a solution of 3.13 g (9.71 mmol) of 6-(3,3-dimethylpiperazin-1-yl)-8-methyl-2- (pyrid-4-yl}imidazo[1,2-b]pyridazine in 80 ml of dichloromethane are added at room temperature 19.4 mi (19.4 mmol) of a 1M solution of iodine chloride in dichloromethane. After reaction for 2 hours, the solution is poured into 150 mi of water and basified by addition of sodium bicarbonate, and the resulting mixture is decolorized by portionwise addition of sodium thiosulfate. The organic phase is separated out, dried over sodium sulfate and concentrated under reduced pressure to give a brown oil, which is purified by chromatography on a column of 120 g of silica gel, eluting with a mixture of dichloromethane, methanol! and aqueous ammonia (90/1011), to give 3.35 g of 6~(3,3-dimethylpiperazin-1-yl)-3-iodo-8-methyl-2-(pyrid-4- yl)imidazo[1,2-b]pyridazine in the form of a beige-coloured solid. m.p.:153-155°C

TH NMR (CDCl) 8: 8.75 (d, 2H); 8.15 (d, 2H); 6.75 (s, 1H); 3.70 (m, 2H); 3.40 (s, 2H); 3.20 (m, 2H); 2.70 (s, 3H); 1.30 (s, 6H) ppm.

Step 2.7. 6-(3,3-Dimethylpiperazin-1 -y1)-8-methyl-2,3-bis(pyrid-4-yl)imidazo[1,2- blpyridazine

CH, =~ =N —

He— ON N

ARSE

=N

To a mixture of 0.40 g (0.89 mmol) of 6-(3,3-dimethylpiperazin-1-yl)-3-iodo-8-methyl- 2-(pyrid-4-yl)imidazo[1,2-b]pyridazine and 0.155 g (1.07 mmol) of (4-pyridyhboronic acid (CAS 1692-15-5) in 15 ml of a mixture of tetrahydrofuran and water (9/1) are added, after degassing with argon, 0.87 g (2.7 mmol) of caesium carbonate and ’ 0.057 g (0.08 mmol) of a complex of 1,1'- bis(diphenylphosphino)ferrocenedichloropalladium (I) and dichloromethane (PdCl(dppf).CH.Cl, - CAS 851232-71-8). After reaction for 18 hours, the reaction medium is poured into 150 ml of water and the product is extracted with dichloromethane. The organic phase is dried over sodium sulfate and the solvent is evaporated off under reduced pressure. The black oil obtained is purified by chromatography on a column of 40 g of silica gel, eluting with a mixture of dichloromethane, methanol and aqueous ammonia (95/65/0.5) to give 0.039 g of 6- (3,3-dimethylpiperazin-1-yi)}-8-methyl-2,3-bis(pyrid-4-yl)imidazo[1,2-blpyridazine in the form of a beige-coloured powder after recrystallizing from acetonitrile, filtering off and drying. : m.p. = 211-213°C 'H NMR (CDCl) 6: 8.70 (d, 2H); 8.60 (d, 2H); 7.60 (m, 4H); 6.75 (s, 1H); 3.45 (m, 2H); 3.25 (s, 2H); 3.05 (m, 2H); 2.70 (s, 3H); 1.20 (s, 6H) ppm.

Examp le 3 (compound 12): 6-(3,3-Dimethylpiperazin-1-yl)-2,3-bis(pyrid-4- yllimidazo[1,2-b]pyridazine

NN —

MPN rx 7

H.C N N :

HN 7 \ =N

Step 3.1. 6-Chloro-2-(pyrid-4-yl)imidazo[1 ,2-blpyridazine

ZN =N —

Cl N

A mixture of 3.80 g (28.1 mmol) of 3-amino-6-chloropyridazine and 5.00 g (17.8 mmol) of 2-bromo-1-(pyrid-4-yl)ethanone hydrobromide in 50 ml of ethanol is heated by microwave 140°C for 50 minutes. After cooling, the solvent is evaporated off under reduced pressure and the residue is taken up in saturated aqueous sodium hydrogen carbonate solution. The solid is separated out by filtration, washed with water and then chromatographed on a column of silica gel, eluting with a mixture of dichloromethane and methanol (95/5), to give 1.87 g of 6-chloro-2-(pyrid-4- } ylhiimidazo[1,2-b]pyridazine in the form of a yellow powder.

LC/MS: M+H" = 231 "H NMR (CDCls) &: 8.71 (dd, 2H); 8.33 (d, 1H); 7.93 (dd, 1H), 7.82 (dd, 2H); 7.11 (d, 1H). :

Step 3.2. 6-(3,3-Dimethylpiperazin-1 -yl)-2-(pyrid-4-yl)imidazo[1,2-b]pyridazine

LI)

H,C N nN

A mixture of 1.95 g (8.45 mmol) of 6-chloro-2-(pyrid-4-yl)imidazo[1,2-b]pyridazine and 2.4 g (21 mmol) of 2,2-dimethylpiperazine is heated in a microwave oven at 150°C for 13 hours. The medium is then cooled and the solvent is evaporated off under reduced pressure. The orange oil obtained is chromatographed on a column of silica gel, eluting with a mixture of dichloromethane and a 1M solution of ammonia in . methanol (95/5), to give 1.63 g of 6-(3,3-dimethylpiperazin-1-yl)-2-(pyrid-4- yl)imidazo[1,2-b)pyridazine in the form of a yellow foam. .

LC/MS: M+H" = 309 *H NMR (DMSO-d): 8.67 (d, 1H); 8.57 (dd, 2H); 7.86 (m, 3H); 7.23 (d, 1H); 3.41 (m, 2H); 3.25 (s, 2H); 3.17 (d, 1H); 2.84 (m, 2H); 1.95 (bs, 1H); 1.07 (s, 6H).

Step 3.3. 6-(3,3-Dimethylpiperazin-1 -yl}-3-iodo-2-(pyrid-4-yl)imidazo[1,2- blpyridazine

ZN =N — ’ N 1G x NZ \ J

J

:

To a solution of 1.37 g (4.45 mmol) of. 6-(3,3-dimethylpiperazin-1-yl)-2-(pyrid-4- yl)imidazo[1,2-b]pyridazine in 20 mi of chloroform is added a solution of 1.80 g (11.1 mmol) of iodine monochloride in 5 ml of methanol. The suspension obtained is stirred for 2 hours. Saturated aqueous sodium hydrogen carbonate solution is added, followed by portionwise addition of sodium thiosulfate until the reaction medium remains yellow. The solid is separated out by filtration and air-dried to give 1.95 g of ’ the product 6-(3,3-dimethylpiperazin-1 -yl)-3-iodo-2-(pyrid-4-yl)imidazo[1,2- b]pyridazine in the form of a yellow powder. 'H NMR (DMSO-d): 9.0 (bs, 2H); 8.70 (d, 2H); 8.10 (d, 2H); 8.00 (d, 1H); 7.38 (d, 1H); 3.85 (m, 2H); 3.70 (m, 2H); 3.3 (m, 2H); 1.40 (s, 6H).

Step 3.4. 6-(3,3-Dimethylpiperazin-1 ~yI}-2,3-bis(pyrid-4-yl)imidazo[1 ,2-

Za —

MPN EO)

H,C N N

HN. 7/3 ~ blpyridazine_ =N )

After degassing, a mixture of 0.28 g (0.55 mmol) of 6~(3,3-dimethylpiperazin-1-y|)-3- iodo~2-(pyrid-4-yl)imidazo[1,2-b]pyridazine, 0.095 g (0.77 mmol) of (pyrid-4-yl)boronic acid, 0.89 g (2.7 mmol) of caesium carbonate and 45 mg (0.055 mmol) of a complex of 1,1"-bis(diphenylphosphinoferrocene)dichloropalladium (i) and dichloromethane : (PdClx{dppf).CH.Cl, — CAS 851232-71-8) in 4 ml of a mixture of 1,4-dioxane and water (75/2) is heated in a microwave oven at 105°C for 30 minutes. After cooling, - the mixture is diluted with dichloromethane and washed with water. The ‘organic phase is then dried over magnesium sulfate and filtered, and the solvent is evaporated off. The oil obtained is chromatographed on silica gel, eluting with a mixture of a 1M solution of ammonia in a mixture of methanol and dichloromethane (3/97), to give 0.070 g of a yellow powder.

LC/MS: M+H" = 386

H NMR (DMSO-d): 8.70 (d, 2H); 8.54 (d, 2H): 7.96 (d, 1H); 7.60 (d, 2H); 7.51 (4, 2H); 7.34 (d, 1H); 3.45-3.10 (m, 4H); 2.83 (m, 2H); 1.05 (6H).

Example 4 (compound 3): 6-(3.3-Dimethylpiperazin-1-yl)-2-(pyrid-3-yl)-3-(pyrid- 4-yllimidazo[1,2-b]pyridazine

’ H,C 4 \ 7 > NN

HO nN" N

HN. 4 \ =N

Step 4.1. 6-Chloro-2-(pyrid-3-yl)imidazo[1 ,2-b]pyridazine = —N — nS _N J \ / }

Cl” ON N

A suspension of 2.80 g (11.9 mmol) of 3-amino-6-chloropyridazine, 3.69 g (13.2 : mmol) of 2-bromo-1-(pyrid-3-yi)ethanone hydrobromide and 3.7 ml (26 mmol) of triethylamine in 45 ml of ethanol is heated by microwave at 140°C for 50 minutes. . After cooling, the solvent is evaporated off under reduced pressure and the residue is purified by chromatography on a column of 120 g of silica gel, eluting with a mixture of dichloromethane and methanol (95/5) to give 0.77 g of product in the form of a beige-coloured powder, after triturating in heptane, filtering off and drying under reduced pressure.

LC/MS: M+H" = 231 "H NMR (DMSO-d): 9.25 (s, 1H); 9.00 (s, 1H); 8.60 (d, 1H); 8.40 (dt, 1H); 8.25 (d, 1H); 7.50 (dd, 1H); 7.40 (d, 1H). : :

Step 4.2. 6-(3,3-Dimethylpiperazin-1 -yi}-2-(pyrid-3-yl)imidazo[1,2-b]pyridazine

LIC)

H,C /

HN]

A mixture of 0.77 g (3.3 mmol) of 6-chloro-2-(pyrid-3-yl)imidazo[1,2-b)pyridazine and 11 g (9.6 mmol) of 2,2-dimethylpiperazine in 7 ml of ethanol is heated in a microwave oven at 150°C for 13 hours. The medium is then cooled and the solvent is evaporated off under reduced pressure. The orange oil obtained is chromatographed on a column of silica gel, eluting with a mixture of dichloromethane and a 1M solution of ammonia in methanol (97/3), to give 0.89 g of 6-(3,3-dimethylpiperazin-1-y)-2- (pyrid-3-yljimidazo[1,2-b]pyridazine in the form of a yellow powder.

eo -29-

LC/MS: M+H" = 309 'H NMR (DMSO-ds): 9.14 (d, 1H); 8.56 (s, 1H); 8.48 (d, 1H); 8.23 (d, 1H); 7.85 (d,

TH); 7.45 (dd, 1H); 7.20 (d, 1H); 3.41 (t, 2H); 2.86 (t, 2H); 1.95 (bs, 2H); 1.08 (s, 6H).

Step4.3. 6-(3,3-Dimethylpiperazin-1-yl)-3-iodo-2-(pyrid-3-yl)imidazo[1 2- b]pyridazine r—C

H.C / 3 x J \

HO NI

HN. I

To a solution of 0.870 g (2.82 mmol) of 6-(3,3-dimethylpiperazin-1-yl)-2-(pyrid-3- yhimidazo[1,2-b]pyridazine in 10 ml of chloroform Is added a solution of 0.600 g (3.70 mmol) of iodine monochloride in 4 ml of methanol. The orange-coloured suspension is then stirred for 3 hours and the solvent is evaporated off under reduced pressure to give a residue. Saturated aqueous sodium hydrogen carbonate solution is then added, followed by portionwise addition of sodium thiosulfate until the reaction mixture remains yellow. The solid is separated out by filtration and air-dried to give 0.90 g of product 6~(3,3-dimethylpiperazin-1-yl)-3-icdo-2-(pyrid-3-yl)imidazo[1 ,2- b]pyridazine in the form of a beige-coloured powder.

LC/MS: M+H" = 435

H NMR (DMSO-dg): 9.26 (s, 1H); 8.57 (d, 1H); 8.39 (d, 1H); 7.92 (d, 1H); 7.52 (dd, 1H); 7.31 (d, 1H); 3.75-3.10 (m, 6H); 1.25 (s, 6H).

Step 4.4. 6-(3,3-Dimethylpiperazin-1 -y1)-2,3-bis(pyrid-3-yl)imidazo[1,2- blpyridazine =

H.C /

HC SN 4N / \ N

HN 7 \

As

After degassing, a mixture of 0.400 g (0.92 mmol) of 6-(3,3-dimethylpiperazin-1-yl)-3- iodo-2-(pyrid-3-yl)imidazo[1 .2-blpyridazine, 0.150 g (1.22 mmol) of (pyrid-4-yl)boronic acid, 0.89 g (2.7 mmol) of caesium carbonate and 75 mg (0.092 mmol) of a complex of 1,1-bis(diphenylphosphinoferrocenedichioropalladium (I) and dichloromethane (PdClx(dppf).CH.Cl) in 6 ml of a mixture of 1,4-dioxane and water (3/1) is heated in a microwave oven at 105°C for 30 minutes. After cooling, the mixture is diluted with dichloromethane and washed with water. The organic phase is then dried over magnesium sulfate and filtered, and the solvent is evaporated off to give a green oil. iN

The oil obtained is chromatographed on a column of 25 g of silica gel, eluting with a mixture of a 1M solution of ammonia in methanol and dichloromethane (5/95) to give 0.170 g of 6-(3,3-dimethylpiperazin-1-yl}-2,3-bis(pyrid-3-yl)imidazo[1 ,2-b]pyridazine in the form of a grey powder.

LC/MS: M+H" = 386 oo "HNMR (DMSO-d): 8.70 (d, 1H); 8.67 (d, 2H); 8.52 (d, 1H); 7.96 (d, 1H); 7.90 (d, ~ 1H); 7.58 (d, 2H); 7.41 (dd, TH); 7.33 (d, 1H); 3.40 (t, 2H); 3.25 (s, 2H); 2.84 (t, 2H); 1.06 (s, 6H).

Example 5 (compound 22): 2-(2-Fluoropyrid-4-yi)-6-(4-isopropylpiperazin-1-yl)- 3-(pyrid-4-yl)imidazo[1,2-b]pyridazine

F

. ZN =N — yo x N J \

ON N

CH, N

Step 5.1. 6-Amino-3-chloro-1 -(ethoxycarbonylmethyl)pyridazin-1-ium bromide

Cx x NC Br cl” TN” 1 07 0" cH,

A mixture of 25.6 g (198 mmol) of 3-amino-8-chloropyridazine in 230 ml of hot ‘ ethanol is treated with 34.0 g (206 mmol) of ethyl bromoacetate. After refluxing for 24 hours, the mixture is cooled and the crystals are separated out by filtration. 36.6 g of product are isolated after drying. A further 7.1 g are isolated by evaporating off the 9 solvent under reduced pressure and recrystallizing from ethanol. 'H NMR (DMSO-dg) &: 9.8 (broad signal, 1H); 9.4 (broad signal, 1H); 8.0 (d, AH), 7.7 (d, 1H); 6.3 (s, 1H); 4.1 (d, 2H); 1.2 (t, 3H) ppm. me

Step 5.2. 2-Bromo-6-chloroimidazo[1,2-b]pyridazine and 2,6-dibromoimidazo[1,2- bjpyridazine / Br NY NJ) r a SN Br” “N7

A mixture of 20 g (65 mmol) of 6-amino-3-chloro-1-(ethoxycarbonylmethyl)pyridazin- 1-ium bromide and 63 g of phosphorus oxybromide in 50 ml of toluene is heated at 160°C for 3 hours. The mixture is then poured onto ice (300 ml). After stirring, the solid is separated out by filtration and then purified by chromatography on a column of 120 g of silica gel, eluting with a mixture of 0 to 10% of methanol in dichloromethane. 8.05 g of a mixture of the two products are thus obtained, and are : used without further purification for the rest of the synthesis. 'H NMR (CDCl) 8: 7.92 (s, 1H); 7.83 (d, 1H); 7:1 (d, 1H) : :

Step 5.3. 2-Bromo-6-(4-isapropylpiperazin-1-yl)imidazo[1,2-b]pyridazine

ZN

Br

NS ND

ON N

Hos

CH, :

The mixture of 3.98 g (14.4 mmol) of 2-bromo-6-chloroimidazo([1,2-blpyridazine and 2,6-dibromoimidazo[1,2-blpyridazine obtained in the preceding step and 3.7 g (28.5 mmol) of 1-isoproylpiperazine in 15 ml of ethanol is heated at 160°C for 8 hours in a sealed tube in a microwave reactor. The mixture is diluted with ethanol and then filtered to give 249 ¢g of 2-bromo-6-(4-isopropylpiperazin-1-yl)imidazo[1,2- ’ blpyridazine. : 'H NMR (CDCl3) 5: 7.62 (s, TH); 7.60 (d, 1H); 6.2 (d, 1H); 3.5 (m, 4H); 2.73 (m, 1H); 2.64 (m, 4H); 1.1 (d, 6H)

Step 5.4. 2-Bromo-3-iodo-6-(4-isopropylpiperazin-1-yl)imidazo|1 ,2-blpyridazine

LX

Sy SN 4

Ho

CH,

A solution of 2.45 g (14.8 mmo!) of iodine chloride in 2 ml of methanol is added dropwise to a solution of 2.45 g (7.56 mmol) of 2-bromo-6-(4-isopropylpiperazin-1- yl)imidazo[1,2-b]pyridazine in 20 ml of chloroform at 0°C. The mixture is stirred at room temperature for 4 hours. The mixture is then triturated with sodium thiosulfate.

This mixture is concentrated under reduced pressure in the presence of 15 g of silica gel. The residue is deposited on a column of 80 g of silica gel and is purified by chromatography, eluting with a gradient of from 0 to 10% methanol in dichloromethane, to give 2.07 g of 2-bromo-3-iodo-6-(4-isopropylpiperazin-1- yl)imidazo[1,2-b]pyridazine in the form of an orange-coloured solid. "MH NMR (CDCls) 6: 7.5 (d, 1H); 6.9 (d, 1H); 3.55 (m, 4H); 3.19 (m, 4H), 3.17 (m, 1H); 1.32 (d, 6H)

Step 5.5. 2-Bromo-6-(4-isopropylpiperazin-1 -yi)-3-(pyrid-4-yl}Yimidazo[1,2- blpyridazine cr Br

ON SN { : Ho Ne 4 \

CH, =N

A mixture of 0.089 g (0.12 mmol) of 2-bromo-3-iodo-6-(4-isopropylpiperazin-1- yl)imidazo[1 ,2-b]pyridazine, 3 mg (0.004 mmol} of 1.1- bis(diphenylphosphino)ferrocenepalladium dichloride (CAS 72287-26-4), 18 mg (0.15

: | -33- mmol) of pyrid-4-ylboronic acid (CAS 1692-15-5), 0.9 ml of aqueous 2M caesium ’ carbonate solution and 1.5 ml of 1,4-dioxane in a sealed tube is heated at 110°C for 30 minutes in a microwave oven. 1 ml of saturated sodium chloride solution and 4 ml of ethyl acetate are added. After stirring, the mixture is percolated through a sodium sulfate cartridge.

The solvent is evaporated off to dryness in the presence of silica gel. The absorbed residue is deposited on a column of 4 g of silica gel and diluted with a gradient of from 0 to 6% methanol and 1% aqueous ammonia in dichloromethane, to give 8.5 mg of 2-bromo-6-{4-isopropylpiperazin-1 -yl)-3~(pyrid-4-yl)imidazo[1,2-b]pyridazine.

H NMR (CDCls) 8: 8.74 (d, 2H); 7.94 (d, 2H); 7.7 (d.1H); 6.93 (d, 1H); 3.5 (m, 4H); 2.75 (m, 1H); 2.65 (m, 4H); 1.10 (d, 6H).

Step 5.6. 2-(2-Fluoropyrid-4-yf)-6-(4-isopropylpiperazin-1 -yl}-3~(pyrid-4- ybhimidazo[1,2-blpyridazine

F

TC cr 7 NN oN N

H,C NS 4 ) 1. =N : :

A mixture of 2.65 g (6.6 mmol) of 2-bromo-6-(4-isopropylpiperazin-1-yl)-3-(pyrid-4- yllimidazo[1,2-b]pyridazine, 0.46 g (0.65 mmol) of 1,1- bis(diphenylphosphino)ferrocene palladium (CAS 72287-26-4), 1.12 g (9.10 mmol) of pyridine-4-boronic acid (CAS 169215-1 5-5) and 15 ml of aqueous 2M caesium carbonate solution in 25 ml of 1,4-dioxane in a sealed tube is heated at 120°C for 20 minutes. A further 0.237 g (2.7 mmol) of pyridine-4-boronic acid is added and the reaction mixture is heated at 110°C for 30 minutes. The reaction medium is then diluted with water and the product is extracted with Sthyl acetate. The organic phase is washed with saturated aqueous sodium chloride solution and then dried over sodium sulfate. The solvent is stripped off under reduced pressure and the residue is adsorbed on silica gel. The product is purified by chromatography on a column of 80 g of silica gel, eluting with a gradient of from 0 to 10% methanol in dichloromethane to give 1.85 g of 2~(2-fluoropyrid-4-yl)-6-(4-isopropylpiperazin-1-yl)-3-(pyrid-4- ’ yhiimidazo[1,2-b]pyridazine, after recrystallizing from isopropanol. m.p. = 196-198°C 'H NMR (CDCl3) 8: 8.74 (d, 2H); 8.15 (d, 1H); 7.80 (d, 1H); 7.56 (d, 2H); 7.39 (d, 1H); 7.25(d, 1H); 6.98 (d, 1H); 3.50 (m, 4H); 2.76 (m, 1H); 2.62 (m, 4H); 1.08 (d, 6H).

Table 1 below illustrates the chemical structures and the physical properties of a number of compounds according to the invention.

In this table: - the column “m.p. °C” indicates the melting points of the products in degrees Celsius. “N.D" means that the melting point is not determined, - the column “[a]y” indicates the result of analysis of the optical rotation of the compounds of the table at a wavelength of 580 nm; the solvent indicated in parentheses corresponds to the solvent used for measuring the optical rotation, in degrees, and the letter “¢” indicates the concentration of the solvent in g/100 ml. “N.A." means that the optical rotation measurement is not applicable, - the column “m/z” indicates the molecular ion (M+H") observed by analysis of the products by mass spectrometry, either by LC-MS (liquid chromatography coupled to

Mass Spectroscopy) performed on a machine of Agilent LC-MSD Trap type in positive ES] mode, or by direct introduction by MS (Mass Spectroscopy) on an - Autospec M (EBE) machine using the DCI-NH3 technique or using the electron impact technique on a machine of Waters GCT type. - “CHs-" means methyl, -“CH3OH” means methanol, - "DMSO" means dimethyl sulfoxide, !

TABLE 1 . Ry - 5

NN

B 4 \ ~N Rs [alo (°)

R m.p m/z . | (solvent -N-A-L-B- (M+H 7 .°C c; in ) g/100 m) 1 (35)-3-Methylpiperazin-1-yl [H [H | Pyrid- 196 | 372 +9.0 3-vl - (CH30H; : 202 0.535) 2 | (3S)-3-Methylpiperazin-1-yl |[H [H Pyrid- | CH [129 | 386 2.2 3-yi 3 |- (CH30H; 130 0.37) 3 | 3,3-Dimethylpiperazin-1-yl H Pyrid- | H 169 | 386 N.A. 3-yl - - 171 } 4-lsopropylpiperazin-1-yl HH Pyrid- 139 | 400 N.A. 3yl - 148 o Z-Isopropylpiperazin-i -yl H |H Pyrid- [CH [63- | 414 N.A.

Ce re Te (35)-3-Methylpiperazin-1-yl [| H | H | 5- H 172 | 390 +8.2

Fluoro - (CH30H; pyrid- 173 0.51) 3-yl oe | RO] i m.p . | (solvent -N-A-L-B- : Rs (M+H .°C cin ) g/100 m) 7 | (35)-3-Methylpiperazin-1-yl | H | H 5- CH | 147 | 404 -3.5

Fluoro | 3 - (CH30H; pyrid- 148 0.54)

KY

4-Isopropylpiperazin-1-yi H 5- H 1171 | 418 N.A.

Fluoro - pyrid- 182 3-vi 4-Isopropylpiperazin-1-yl H|H 5- CH | 142 | 428 N.A.

Methyl | 2 - pyrid- 147 3-yl

Piperazin-1-yl H Pyrid- | H 183 | 358 N.A. 4-yl - 189 11 | (35)-3-Methylpiperazin-1-yl [H |H |Pyrid- | CH | 55- | 386 Not me a 12 | 3,3-Dimethylpiperazin-1-yl |H | H Pyrid- | H 149 | 386 N.A, 4-yl - 152 13 | 3,3-Dimethylpiperazin-1-yl |H | H Pyrid- | CH | 185 | 400 N.A. 4-yl 3 -

TERRE

14 | 3,3-Dimethylpiperazin-i-yl |H | CH [Pyrid- |H [211 | 400 N.A. : 3 4-yl - 213 | (3R)-3-Isopropyipiperazin- | H Pyrid- 189 | 400 +2.9 1-yl 4-yl - (DMSO; : 191 0.847)

wo 2010/070238 PCT/FR2009/052594 : _37- [ado (°)

R m.p m/z . (solvent -N-A-L-B- (M+H 7 .°C Cc; in ) g/100 my) 16 | 4-Isopropylpiperazin-1-yl Pyrid- 66- | 400 N.A.

CE EE

17 | 4-Isopropylpiperazin-1-yl |H | H Pyrid- | CH [195 [414 [NA

Cm eT 18 | (cis)-5- HH Pyrid- [H 189 | 398 N.A.

EF

4-c]pyrrol-2(1H)-yl 4-Pyrrolidin-1-ylpiperidin-1- {[H | H Pyrid- 187 | 426 N.A. vi 4-yl - 189 | (35)-3-Methylpiperazin-1-yl | H | H 2- H 1150 | 390 +8.2 : Fluoro |= (CH30H; pyrid- 152 0.51) 4-yl 21 | (3S)-3-Methylpiperazin-1-yl [H [H | 2- CH [128 | 404 -0.9

Fluoro | 3 - (CH;0H;

So pyrid- 135 0.53) 4-y 22 | 4-Isopropylpiperazin-1-yl 1H |H | 2- H [196 [418 | N.A.

Fluoro - pyrid- 198 4-yl 23 | 4-lsopropylpiperazin-1-yl HH 2- CH | 129 | 432 N.A.

Fluoro | 3 - pyrid- 130 4-yl

Biological examples

The capacity of the compounds of the invention to inhibit the phosphorylation of casein by casein kinases 1 epsilon and delta may be evaluated according to the procedure described in document US 2005/0 131 012.

Filter-plate assay of ATP-**P for the screening of CK1epsilon inhibitors:

The effect of the compounds on inhibition of the phosphorylation of casein by the enzyme casein kinase 1 epsilon (CK1 epsilon) is measured, using a casein assay via filtration of ATP-*P in vitro.

Casein kinase 1 epsilon (0.58 mg/ml) is obtained via fermentation and purification processes performed according to methods that are well known to those skilled in the art, or may also be obtained from Invitrogen Corporation™ (human CK1 epsilon).

The compounds are tested at five different concentrations so as to generate ICs values, i.e. the concentration at which a compound is capable of inhibiting the enzymatic activity by 50%, or alternatively the percentage of inhibition at a concentration of 10 micromolar. oo “U-bottomed Falcon plates are prepared by placing 5 pL of solutions of the compounds according to the invention at concentrations of 10, 1, 0.1, 0.01 or 0.001" uM in different wells.

The solutions of the compounds according to the invention .at these various concentrations are prepared by diluting in a test buffer (Tris 50 mM pH 7.5, MgCl, 10

M, DTT 2 mM and EGTA 1 mM) a stock solution in DMSO at a concentration of 10 mM. Next, 5 pL of dephosphorylated casein are added to a final concentration of 0.2 pg/pL, 20 pL of CK1 epsilon to a final concentration of 3 ng/uL, and 20 uL of ATP-3p to a final concentration of 0.02 pCi/uL mixed with cold ATP (10 pM final - approximately 2x10% CPM per well). The final total test volume per well is equal to 50 aL.

i -39-

The “U’-bottomed Falcon® test plate mentioned above is vortexed, and then incubated at room temperature for 2 hours. After 2 hours the reaction is stopped by adding an ice-cold solution of 65 pL of cold ATP (2 mM) prepared in test buffer. 100 pL of the reaction mixture are then transferred from the “U"-bottomed Falcon® plate into Millipore® MAPH filter plates, preimpregnated with 25 pL of ice-cold 100%

TCA.

The Millipore MAPH filter plates are agitated gently and are left to stand at room temperature for at least 30 minutes to precipitate the proteins.

After 30 minutes, the filter plates are sequentially washed and filtered with 2x150 pL of 20% TCA, 2x150 pL of 10% TCA and 2x150 HL of 5% TCA (6 washes in total per plate/900 pL per well). : co

The plates are left to dry overnight at room temperature. Next, 40 uL of Microscint-20

Packard® scintillation liquid are added per well and the plates are closed in a leaktight manner. The radiation emitted by each well is then measured for 2 minutes in a TopCount NXT Packard® scintillation counter, in which the values of CPM/well are measured.

The percentage inhibition of the capacity of the enzyme fo phosphorylate the substrate (casein) is determined for each concentration of test compound. These ‘25 inhibition data expressed as percentages are used to calculate the ICsq value for each compound compared with the controls.

The kinetic studies determined the Kyl value for ATP as being 21 uM in this test system.

Table 2 below gives the ICs, values for the inhibition of phosphorylation of casein kinase 1 epsilon for a number of compounds according to the invention.

Table 2 i -40-

No. : [TT me

Under these conditions, the compounds of the invention that are the most active have 1Csy values (concentrations that inhibit 50% of the enzymatic activity of casein : kinase 1 epsilon) of between 1 nM and 2 UM. 5 . .

The capacity of the compounds of the invention to inhibit the phosphorylation of casein by the casein kinases 1 epsilon and delta may be evaluated using an FRET (Fluorescence Resonance Energy Transfer) fluorescence test with the aid of the "Z'Lyte™ kinase assay kit” (reference PV3670: Invitrogen Corporation™) according to the manufacturer's instructions.

The casein kinases 1 used are obtained from Invitrogen Corporation (human CK1 epsilon PV3500 and human CK1 delta PV3665).

A peptide substrate labelled at both ends with a fluorophore-donating group (coumarin) and a fluorophore-accepting group (fluorescein) constituting an FRET system is dephosphorylated in the presence of ATP by casein kinase 1 epsilon or delta in the presence of increasing concentrations of compounds of the invention.

The mixture is treated with a site-specific protease that specifically cleaves the substrate peptide to form two fluorescent fragments having a large fluorescence “emission ratio.

The fluorescence observed is thus related to the capacity of the products of the invention to inhibit the phosphorylation of the substrate peptide by casein kinase 1 epsilon or casein kinase 1 delta. :

The compounds of the invention are dissolved at different concentrations starting with a 10 mM stock solution in DMSO diluted in a buffer containing 50 mM HEPS, pH 7.5, 1 mM EGTA, 0.01% Brij-35, 10 mM MgCl; for casein kinase 1 epsilon and supplemented with Trizma Base (50 mM), pH 8.0 and NaN; (0.01% final) for casein kinase 1 delta.

The phosphorylation of the substrate peptide SER/THR 11 obtained from Invitrogen

Corporation™ is performed at a final concentration of 2 MM. The ATP concentration is 4 times the Ky, this value being 2 uM for casein kinase 1 epsilon and 4 uM for casein kinase 1 delta. .

The emitted fluorescence is measured at wavelengths of 445 and 520 nm (excitation at 400 nm).

Table 3 below gives the ICs, values for the inhibition of phospharylation of casein kinase 1 delta for a number of compounds according to the invention.

Table 3

Compound | 411 delta ICs (nM)

No.

Under these conditions, the compounds of the invention that are the most active have ICs values (concentration that inhibits 50% of the enzymatic activity of casein kinase 1 delta) of between 1 nM and 2 uM.

It is thus seen that the compounds according to the invention have inhibitory activity on the enzyme casein kinase 1 epsilon or casein kinase 1 delta. | .

Experimental protocols for circadian cell assay

‘WO 2010/070238 PCT/FR2009/052594 . -49-

Mperi-luc Rat-1 (P2C4) fibroblast cultures were prepared by dividing the cultures every 3-4 days (about 10-20% of confluence) on 150 cm? degassed polystyrene tissue culture flasks (Falcon® # 35-5001) and maintained in growth medium [EMEM (Celigro #10-010-CV); 10% foetal bovine serum (FBS; Gibco #16000-044); and 50 [.U./mL of penicillin-streptomycin (Cellgro #30-001-Cl)] at 37°C and under 5% CO,.

Cells obtained from Rat-1 fibroblast cultures at 30-50% of confluence as described above were co-transfected with vectors containing the selection marker for resistance to zeocin for a stable transfection and a luciferase reporter gene directed by the promoter mPer-1. After 24 to 48 hours, the cultures were divided on 96-well plates and maintained in growth medium supplemented with 50-100 Mg/mL of zeocin (Invitrogen® #45-0430) for 10-14 days. The zeocin-resistant stable transfectants were evaluated for expression of the reporter by adding to the growth medium luciferin 100 uM (Promega® #E1603®) and by assaying the luciferase activity on a

TopCount® scintillation counter (Packard model #C384V00). The Rat-1 cell clones expressing both zeocin resistance and luciferase activity directed by mPer1 were : serum-shock-synchronized with 50% horse serum [HS (Gibco® #1 6050-122)] and the activity of the circadian reporter was evaluated. The P2C4 clone of fibroblasts

Mper1-iuc Rat-1 was selected to test the compound. oo

The Mper1-luc Rat-1 (P2C4) fibroblasts at 40-50% of confluence obtained according to the protocol described above were plated out onto 96-well opaque tissue culture plates (Perkin Elmer® #6005680). The cultures are maintained in growth medium supplemented with 100 pg/mL of zeocin (Invitrogen #45-0430) until they reached 100% of confluence (48-72 hours). The cultures were then synchronized with 100 pL of synchronization medium [EMEM (Cellgro #10-010-CV); 100 I.U./mL of penicillin- streptomycin (Celigro #30-001-C1); 50% HS (Gibco #16050-122)] for 2 hours at 37°C and under 5% CO,. After synchronization, the cultures were rinsed with 100 ML of

EMEM (Celigro #1 0-010-CV) for 10 minutes at room temperature. After rinsing, the

Bh medium is replaced with 300 WL of CO-independent medium [CO,l (Gibco #18045- 088); L-glutamine 2 mM (Cellgro #25-005-C1); 100 U.L/mL of penicillin-streptomycin (Cellgro #30-001-C1); luciferin 100 HM (Promega #E 1603)]. The compounds of the invention tested for the circadian effects were added to COz-independent medium in : DMSO at 0.3% (final concentration). The cultures were immediately closed in a leaktight manner with TopSeal-A® film (Packard #6005185) and transferred for the luciferase activity measurement.

After synchronization, the test plates were maintained at 37°C in a tissue culture oven (Forma Scientific Model #3914). The in vivo luciferase activity was estimated by measuring the relative light emission on a TopCount scintillation counter (Packard model #C384V00).

The period analysis was performed either by determining the interval between the relative light emission minima over several days or by Fourier transform. The two methods produced a virtually identical period estimation on a range of circadian periods. The power is given in EC Delta (t+1h), which is presented as the effective micromolar concentration that induce a 1-hour prolongation of the period. The data were analysed by adjusting a hyperbolic curve to the data expressed as change of period (y-axis) as a function of the concentration of the test compound (x-axis) in the

XLfit™ software and the EC Delta (t+1h) was interpolated from this curve.

Table 4 below gives the EC Delta (t+1h) for a number of compounds according to the invention.

Table 4

No. : vm 3

Under these conditions, the compounds of the invention that are the most active have EC Delta (t+1h) values (effective micromolar concentration that induced a 1- hour prolongation of the period) of between 1 nM and 2 pM.

By inhibiting the enzymes CK1 epsilon and/or CK1delta, the compounds that are the ’ subject of the invention modulate the circadian periodicity, and may be useful for treating circadian rhythm disorders.

The compounds according to the invention may especially be used for the preparation of a medicament for preventing or treating sleep disorders; circadian rhythm disorders, especially such as those caused by jetlag or shift work.

Among the sleep disorders that are especially distinguished are primary sleep disorders such as dyssomnia (for example primary insomnia), parasomnia, hypersomnia (for example excessive somnolence), narcolepsy, sleep disorders related to sleep apnoeia, sleep disorders related to the circadian rhythm and other unspecified dyssomnias, sleep disorders associated with medical/psychiatric disorders. ~The compounds that are the subject of the invention also cause a circadian phase shift and such a property may be useful in the context of a potential monotherapy or combined therapy that is clinically effective in the case of mood disorders.

Among the mood disorders that are especially distinguished are depressive disorders : (unipolar depression), bipolar disorders, mood disorders caused by a general medical complaint and also mood disorders induced by pharmacological substances.

Among the bipolar disorders that are especially distinguished are bipolar | disorders and bipolar ll disorders, especially including seasonal affective disorders.

The compounds that are the subject of the invention, which modulate the circadian periodicity, may be useful in the treatment of anxiety and depressive disorders caused in particular by an impairment in the secretion of CRF.

Among the depressive disorders that are especially distinguished are major depressive disorders, dysthymic disorders and other unspecified depressive disorders.

The compounds that are the subject of the invention, which modulate the circadian ' periodicity, may be useful for preparing a medicament for treating diseases related to dependency on abuse substances such as cocaine, morphine, nicotine, ethanol and cannabis.

By inhibiting casein kinase 1 epsilon and/or casein kinase 1 delta, the compounds according to the invention may be used for preparing medicaments, especially for preparing a medicament for preventing or treating diseases related to hyperphosphorylation of the tau protein, especially Alzheimer's disease.

These medicaments also find their use in therapy, especially in the treatment or prevention of diseases caused or exacerbated by the proliferation of cells and in particular of tumour cells.

As tumour cell proliferation inhibitors, these compounds are useful in the prevention . and treatment of liquid tumours such as leukaemias, solid tumours that are both primary and metastatic, carcinomas and cancers, in particular: breast cancer: lung cancer; small intestine cancer and colorectal cancer; cancer of the respiratory pathways, of the oropharynx and of the hypopharynx; cancer of the oesophagus; liver cancer, stomach cancer, cancer of the bile ducts, cancer of the bile vesicle, pancreatic cancer; cancers of the urinary pathways including the kidney, urothelium and bladder; cancers of the female genital tract, including cancer of the uterus, of the cervix, of the ovaries, choriocarcinoma and trophoblastoma; cancers of the male genital tract, including cancer of the prostate, of the seminal vesicles, of the testicles and germinal cell tumours; cancers of the endocrine glands, including cancer of the thyroid, of the pituitary and of the adrenal glands; skin cancers including : haemiangiomas, melanomas and sarcomas, including Kaposi's sarcoma; brain, nerve, eye or meningeal tumours, including astrocytomas, gliomas, glioblastomas, retinoblastomas, neurinomas, neuroblastomas, schwannomas and meningiomas; malignant haematopoietic tumours; leukaemias (Acute Lymphocytic Leukaemia (ALL), Acute Myeloid Leukaemia (AML), Chronic Myeloid Leukaemia (CML), Chronic lymphocytic leukaemia (CLL)) chloromas, plasmocytomas, T or B cell leukaemias,

Hodgkin or non-Hodgkin lymphomas, myelomas and various malignant haemopathies.

~~ -46-

The compounds according to the invention may also be used for the preparation of medicaments, especially for the preparation of a medicament for preventing or treating inflammatory diseases especially such as inflammatory diseases of the central nervous system, for instance multiple sclerosis, encephalitis, myelitis and encephaiomyelitis, .and other inflammatory.. diseases, for instance vascular pathologies, atherosclerosis, joint inflammations, arthrosis and rheumatoid arthritis.

The compounds according to the invention may thus be used for the preparation of medicaments, in particular of medicaments for inhibiting casein kinase 1 epsilon and/or casein kinase 1 deita.

Thus, according to another of its aspects, a subject of the invention is medicaments comprising a compound of formula (lI), or an addition salt thereof with a pharmaceutically acceptable acid, or alternatively a hydrate or solvate of the compounds of formula (1).

According to another of its aspects, the present invention relates to pharmaceutical compositions comprising, as active principle, a compound according to the invention.

These phamaceutical compositions contain an effective dose of at least one ‘compound according to the invention or a pharmaceutically acceptable salt, a hydrate or solvate of the said compound, and also at least one pharmaceutically acceptable excipient.

The said excipients are chosen, according to the pharmaceutical form and the desired mode of administration, from the usual excipients known to those skilled in the art.

In the pharmaceutical compositions of the present invention for oral, sublingual, subcutaneous, intramuscular, intravenous, topical, local, intratracheal, intranasal, transdermal or rectal administration, the active principle of formula (I) above, or the possible salt, solvate or hydrate thereof, may be administered in unit administration form, as a mixture with standard pharmaceutical excipients, to man and animals for the prophylaxis or treatment of the above disorders or diseases.

The appropriate unit administration forms include oral-route forms such as tablets, soft or hard gel capsules, powders, granules and oral solutions or suspensions, sublingual, buccal, intratracheal, intraocular and intranasal administration forms, inhalation forms, topical, transdermal, subcutaneous, intramuscular or intravenous administration forms, rectal administration forms and implants. For topical administration, the compounds according to the invention may be used in creams, gels, ointments or lotions.

By way of example, a unit administration form of a compound according to the invention in tablet form may comprise the following components:

Compound according to the invention 50.0 mg :

Mannitol . 223.75mg

Croscarmellose sodium 6.0 mg

Corn starch 15.0 mg

Hydroxypropylmethyiceliulose 2.25 mg

Magnesium stearate 3.0 mg

Via the oral route, the dose of active principle administered per day may range from

Co 0.1 to 20 mg/kg, in one or more dosage intakes.

There may be particular cases in which higher or lower dosages are appropriate; such dosages are not outside the context of the invention. According fo the usual practice, the dosage that is appropriate to each patient is determined by the practitioner according to the mode of administration and the weight and response of the said patient.

According to another of its aspects, the present invention also relates to a method for treating the pathologies indicated above, which comprises the administration to a patient of an effective dose of a compound according to the invention, or a pharmaceutically acceptable salt or hydrate or solvate thereof.

Claims (14)

1 - 48 = } Claims

1. Compound of general formula (1) Rg R, ZN =N R A x Nf 2 7 N N Lg 7 =p R, in which: ~ Ra represents a pyridyl group optionally substituted with one or more substituents chosen from halogen atoms and groups Cqg-alkyl; - Rs represents a hydrogen atom or a group Cjz-alkyl; - Arepresents a group Ci-7-alkylene optionally substituted with one or two groups Ry; - B represents a group C,.-alkylene optionally substituted with a group Ry; - L represents either a nitrogen atom optionally substituted with a group R; or Ry, or a carbon atom substituted with a group Re1 and a group Ry or two groups Rep; the carbon atoms of A and B being optionally substituted with one or more groups Rj, which may be identical to or different from each other; - Ra, Ry and R; are defined such that: two groups Rs, may together form a group Ci.g-alkylene; Ra and R, may together form a bond or a group Cie-alkylene; Ra and R; may together form a bond or a group Cig-alkylene; Rp and R; may together form a bond or a group Cqe-alkylene; Rg represents a group chosen from a hydrogen atom and groups Cis-alkyl, Cs7- cycloalkyl, Cs.7-cycloalkyl-Cq¢-alkyl, Cie-alkylthio-C1¢-alkyl, Cis-alkyloxy-C.c- alkyl, Cy.e-fluoroalkyl, benzyl, C+.g-acyl or hydroxy-C.s-alky!; Re1 represents a group -NR4Rs or a cyclic monoamine optionally comprising an oxygen atom, the cyclic monoamine being optionally substituted with one or more substituents chosen from a fluorine atom and groups Csg-alkyl, Cie ’ alkyloxy or hydroxy; two Rez form, with the carbon atom that bears them, a cyclic monoamine optionally comprising an oxygen atom, this cyclic monoamine being optionally substituted with one or more groups R;, which may be identical to or different from each other; Rr represents a group Ci.g-alkyl, Ca.r~cycloalkyl, Cs.r-cycloalkyl-Ci.¢-alkyl, Cie alkyloxy-C..¢-alkyl, hydroxy-C1.c-alkyl, Cie-fluoroalky! or benzyt; Rs and Rs represent, independently of each other, a hydrogen atom or a group Ci¢- alkyl, Cs.7-cycloalkyl or Cs.7-cycloalkyl-Cy.¢-alkyl; Ry and R; represent, independently of each other, a hydrogen atom or a group Cig alkyl; in the form of the base or of an acid-addition salt.

2. Compound of general formula (1) according to Claim 1, characterized in that: -L represents either a nitrogen atom optionally substituted with a group R;or Ry, ora carbon atom substituted with a group Res and a group Ry. oo

3. Compound of general formula (1) according to any one of the preceding claims, characterized in that: - Rp represents a pyridyl group, optionally substituted with one or more substituents chosen from fluorine and a methyl group.

4. Compound of general formula (I) according to any one of the preceding claims, characterized in that: Rrand Rg represent a hydrogen atom or a group Cy.¢-alkyl.

5. Compound of general formula (1) according to any one of the preceding claims, characterized in that: - A represents a group C4.7-alkylene optionally- substituted with one or two groups R,: -Brepresents a group Ci7-alkylene optionally substituted with a group Ry;

i - 50 - - L represents a nitrogen atom optionally substituted with a group R; or Ry: the carbon atoms of A and B being optionally substituted with one or more groups R;, which may be identical to or different from each other;

Ra. Rp and R; are defined such that: two groups R, may together form a group Ciealkylene; Ra and Ry, may together form a bond or a group Cyg-alkylene; Ra and R; may together form a bond or a group Ci.g-alkylene; Ry and R; may together form a bond or a group Cq-alkylene; Rq represents a group chosen from a hydrogen atom and groups Cis-alkyl, Cas cycloalkyl, Cz.r-cycloalkyl-Ci.¢-alkyl, C1.g-alkylthio-Cy.e-alkyl, Ci.g-alkyloxy-Ci.¢- alkyl, C+.¢-fluoroalkyl, benzyl, C,.¢-acyl or hydroxy-C.¢-alkyl; Rr represents a group Ci.e-alkyl, Cs.7-cycloalkyl, Caz-cycloalkyl-Cy.¢-alkyl, Cie alkyloxy-Cy.¢-alkyl, hydroxy-C4.-alkyl, Ci-e-fluoroalkyl or benzyl.

6. Compound of general formula (1) according to any one of the preceding claims, characterized in that: ~~ Arepresents a group Cy7-alkylene optionally substituted with one or two groups R,; ~ B represents a group Cy.7-alkylene optionally substituted with a group Ry; - L represents a carbon atom substituted with a group Res and a group Rg; the carbon atoms of A and B being optionally substituted with one or more groups Ry, which may be identical to or different from each other: Ra, Rp and R; are defined such that: two groups R; may together form a group Cqe-alkylene; Ra and Ry, may together form a bond or a group Cig-alkylene; Ra and R; may together form a bond or a group Cq.g-alkylene; Rb and R; may together form a bond or a group C.g-alkylene;

Ra represents a group chosen from a hydrogen atom and groups Cig-alkyl, Css- : cycloalkyl, Cs.r-cycloalkyl-C1.g-alky, Cis-alkylthio-Cy.s-alkyl, C4¢-alkyioxy-C¢- alkyl, Cq¢-fluoroalkyl, benzyl, C1.¢-acyl or hydroxy-Cs.g-alkyl; Res represents a group -NRsRs or a cyclic monoamine optionally comprising an oxygen atom, the cyclic monoamine being optionally substituted with one or ‘more substituents chosen from a fluorine atom and groups Cie-alkyl, Cis alkyloxy or hydroxy; Rs represents a group Cisalkyl, Cs.r-cycloalkyl, Csr-cycloalkyl-Cig-alkyl, Ci. alkyloxy-C1.¢-alkyl, hydroxy-C1¢-alkyl, C+.s-fluoroalkyl or benzyl; R4 and Rs represent, independently of each other, a hydrogen atom or a group Cis alkyl, Cs.7-cycloalkyl or Ca.r-cycloalkyl-Ce-alkyl.

7. Compound of general formula (1) according to any one of the preceding claims, characterized in that: | : - the cyclic amine formed by —N-A-L-B- represents a (38)-3-methylpiperazin-1-yl, 3,3- dimethylpiperazin-1-y, 4-isopropyipiperazin-1-yl, piperazin-1-yl, (3R)-3- isopropylpiperazin-1-yl, (cis)-5-methylhexahydropyrrolof3,4-clpyrrol-2(1H)-yl or 4- pyrrolidin-1-ylpiperidin-1-yl group; - Ra represents a pyridyl group, optionally substituted with one or more substituents chosen from fluorine and a methyl group; - Rs represents a hydrogen atom or a methyl group; -RrandRg represent a hydrogen atom or a methyl group; in the form of the base or of an acid-addition sal.

8. Process for preparing a compound of general formula (I) according to Claim 1, characterized in that a compound of general formula (an t - = 52 = Re R, AN =N oo x oN / Re Xs N : 7 \ (I = in which Ry, Rs, R7 and Rg are as defined in Claim 1 and Xe represents a halogen, is reacted with an amine of general formula (111) AN [1 (Ha ls oo inwhich A, L and B are as defined in Claim 1.

9. Process for preparing a compound of general formula (I) according to Claim 1, characterized in that a compound of general formula (V) Re JR W AN SAND L—B in which A, L, B, Ry, Ry and Rg are defined according to Claim 1, is reacted with a . mixture of a pyridine derivative of general formula (Va) — R N 3 a MA (Va) in which R3 is defined according to Claim 1 and an alkyl chioroformate, in which the alkyl group represents a Cs.g-alkyl, to obtain a compound of general formula (VI) Ry R, = =N x Nf Rs Amy L—B \ Dr, - } Ve Alkyl 0 0 (Vh)

in which A, L, B, Ry, Rs, Ry and Rg are defined according to Claim 1, the said compound of general formula (V1) is then oxidized using ortho-chloranil.

10. Process for preparing a compound of general formula (I) according to Claim 1, characterized in that a compound of general formula (V) Rg R V oS JR WM L—B in which A, L, B, Rz, Ry and Rg are defined according to Claim 1, is reacted according to an aromatic bromination or iodination reaction, to obtain a compound of general formula (VII) iy “ J (VII) A LB Xs in which A, L, B, Rz, Ry and Rg are defined according to Claim 1 and Xs represents a bromine or iodine atom, and in that a metal-catalysed coupling is camied out between the compound of general formula (VII) obtained and a pyridine derivative of general formula (lla) M FL (lila) = R, in which Rj; is as defined in Claim 1 and M represents a trialkylstannyl group or a dihydroxybonyl or dialkyloxyboryl group

11. Process for preparing a compound of general formula (I) according to Claim 1, characterized in that: ~~ a) a compound of general formula (VIII)

Rg R; = —N Br “_n Pa ATT L—B in which A, L, B, R; and Rg are defined according to Claim 1, is reacted is reacted according to an aromatic iodination reaction to obtain a compound of general formula (1X) R, R; =N Br < _N J (IX) = oN — I LB in which A, L, B, R; and Rs are defined according to Claim 1; b) the compound of general formula (IX) obtained in a) is reacted with a compound of ~ general formula (lla) M OF) (lia) =N Ry in which Rj is defined according to Claim 1 and M represents a trialkylstannyl group or a dihydroxyboryl or dialkyloxyboryl group, to obtain a compound of general formula X) Ry R, ZN =N ~ _N / Br Amy ® L—B / — } Ry N in which A, L, B, Rs, R7 and Rg are defined according to Claim 1; ¢) the compound of general formula (X) obtained in b) is reacted with a compound of general formula (Xa) Ro-M (Xa) in which R; is defined according to Claim 1 and M represents a trialkylstannyl group or a dihydroxyboryl or dialkyloxyboryl group, in the presence of a catalyst.

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12. Medicament, characterized in that it comprises a compound of formula (I) according to any one of Claims 1 to 7, in the form of the base or of a pharmaceutically acceptable acid-addition salt.

13. Pharmaceutical composition, characterized in that it comprises a compound of formula (1) according to any one of Claims 1 to 7, in the form of the base or of a pharmaceutically acceptable acid-addition salt, and also at least one pharmaceutically acceptable excipient. :

14. Use of a compound of general formula (1) according to any one of Claims 1 to 12, for the preparation of a medicament for preventing or treating sleep disorders or circadian rhythm disorders, mood disordes, anxiety and depressive disorders, diseases associated with dependence on abuse substances, diseases related to hyperphosphorylation of the tau protein, diseases caused or exacerbated by cell proliferation or inflammatory diseases.