OA16462A

OA16462A - Diarylpyridazinone derivatives, preparation thereof and use thereof for the treatment of humans.

Info

Publication number: OA16462A
Application number: OA1201300258
Authority: OA
Inventors: Christophe Pignier; Elisabeth Dupontpasselaigue; Roy Isabelle Le; Samuel Mialhe
Original assignee: Pierre Fabre Medicament
Priority date: 2010-12-22
Filing date: 2011-12-20
Publication date: 2015-10-15

Abstract

The present invention relates to diarylpyridazinone derivatives that block the potassium Kv channels (specifically the Kv1.5, Kv4.3, and Kv11.1 channels) and to the use thereof for the treatment of humans. Said compounds have the general formula (I), where R1 and R2 are simultaneously or independently one or more groupings such as : halogen, such as F, Br, C1, a straight or branched C1-C4 alkyl, hydroxy, a straight or branched C1-C4 alkoxy, arylsulfonamido, in which the aryl is optionally replaced with a straight or branched C1-C4 alkyl, or nitrile, as well as the various enantiomers and the mixtures thereof in any proportion, and the pharmaceutically acceptable salts thereof.

Description

DIARYLPYRIDAZINONE DERIVATIVES, PREPARATION

THEREOF AND USE THEREOF FOR THE TREATMENT OF HUMANS

The présent invention concerns diarylpyridazinone dérivatives, préparation thereof and uses thereof for the treatment of humans, as blockers of the potassium Kv channels and more specifically the Kv 1.5, Kv4.3 and Kv 11.1 channels.

The potassium channels represent the largest family of ion approximately 80

2004, 62: 9-33) subdivided into channels in the human genome with genes (Tamargo et al, Cardiovasc. Res.

These potassium channels may be subfamilies: potential or voltageactivated channels (K_v channels) and calcium-activated channels (K_Ca channels) , inwardly rectifying channels (K_ir) and

2-pore potassium channels (K₂p) . The subfamily of potential-activated channels is the most widespread in the human body with virtually ubiquitous distribution in excitable cells (cardiac cells, neurones, striated or smooth muscle cells) and nonexcitable cells such as pancreatic, prostatic and parathyroid cells, etc.

(for review, Gutman G et al,

Pharmacol.

Rev. 2005, 57:

473-508).

The main function of Kv potassium channels in excitable cells is to control the resting membrane potential and the action potential duration (Nerbonne et Kass,

Physiol.

Rev.2005 ;85 :1205-1253).

In this respect, several

Kv channels are involved in this control, both in the cardiac auricles and ventricles.(^

The Kv4.3 channels in conjunction with the KChIP 2 subunits form the current I_to which is involved in the early repolarisation phase of the action potential (AP); the KVLQTl/MinK and hERG channels are involved in the late polarisation phase of the AP (respectively generating the currents I_Ks and I_Kr) Aforesaid channels are uniformly distributed between the cardiac auricles and ventricles. Two other types of potassium channel however display a distribution solely in the auricles. The potential-dependent potassium channels (K_vi.₅) responsible for the current I_Kur and the inwardly rectifying channels activated by acétylcholine (Kir3.1 and Kir3.4 responsible for the current Ιχ-Ach) ·

Changes in membrane electrical activity are observed in many disorders, particularly cardiac disorders involving arrhythmias. Among the latter, atrial fibrillation (AF) is a serious arrhythmia involving completely desynchronised activity of the atrial myocytes resulting in uninterrupted, rapid and irregular electrical activity. AF is induced by the appearance of re-entrant electrical circuits in atrial tissue (Miyasaka Y et al, Circulation 2006, 114 : 119125) . No spécifie antiarrhythmic treatment of the atrial level currently exists in order to reduce the incidence of AF, which therefore represents a major medical necessity (Page et Roden, Nat. Rev. Drug Discov. 2005, 4 : 899-910).

The presence of a large number of simultaneously activated micro-re-entrant anarchie nature of the electrical circuits explains the activity observed

both via the endocavitary route and on the ECG. This arrhythmia generally develops against a background of an atrial myocardium which is pathological from the electrophysiological point of view, the refractory periods of which are too short and highly uneven in relation to one another and hence highly vulnérable to the slightest extrasystole. These abnormalities fall within the context of a phenomenon of myocardial remodelling, following pressure overload or stretching causing morphological changes (hypertrophy, dilation, fibrosis) in addition to modifications in transmembrane ionic current régulation, modifying the electrophysiological characteristics of the atrial myocytes. Given that each bout of AF maintains or even worsens this process of mechanical and electrophysiological remodelling, it is understandable that AF has a high potential for récurrence and its naturel évolution is towards chronicity. Conversely, instances of AF of the focal type hâve recently been identified, originating at a spécifie point which is almost always observed to be an extension of the atrial myocardium into the pulmonary veins. These fairly rare cases of AF adopt a fairly monomorphic character, at any rate comparable to the atrial extrasystoles at the outset of the bout or intermittently observed between the attacks. In ail cases, loss of the atrial systole results in a réduction in cardiac output varying between 20 and 30 % and ail the more pronounced in that the latter is diminished in the basal state. In parallel, existence of blood stasis in the atrial^

cavities, particularly in some culs-de-sac such as the auricles, accounts for the thromboembolitic risk. However, the risk of embolism is only partly influenced by the mere presence of AF, with the atrial stasis also being related to the increase in the intracavitary pressures (systolic or diastolic left ventricular dysfunction, valvulopathy or prosthetic valve).

Electrical remodelling therefore constitutes the major substrate of the genesis of AF; it is the resuit of a réduction in the activity of the L-type calcium channels, allowing the Kvl.5 potassium channels to fully exercise their repolarising rôle by means of the ultra-rapid potassium current (Bhakta et Miller, Expert Opin. Ther. Targets 2007, 11 : 1161-1178). The resuit is a dramatic réduction in the refractory period which represents the precipitating factor for the micro-reentries. With the knowledge that the Kvl.5 potassium channels are not functionally expressed at the ventricular level, a blocker of these channels will therefore represent a sélective antiarrhythmic of the atrial level without affecting ventricular electrophysiology. Its pharmacological effect manifests itself in an extension of the refractory period and therefore less effect of the micro-re-entrant circuits. A number of experimental data obtained with reference products confirm the value of Kvl.5 blocking as a therapeutic target (Gôgelein et al, Naunyn Schmiedeberg's Arch Pharmacol 2004, 370 : 183-192, Regan et al, J Pharmacol Exp Ther 2008, 324 : 322-330) .

« j

The rapid changes in the membrane potential are well known in excitable cells, but slow variations in potential are observed in ail cells and are associated with control of the cell cycle, The cell cycle is a key parameter in cell behaviour which needs to be regulated and coordinated for development, tissue régénération and cell prolifération (Pardo, Physiology, 2004 ;19 :285-292 ; Blackistion et al, Cell Cylce, 2009 ;8-21 : 3527-3536). Generally speaking, blocking of the potassium channels leads to a decrease in prolifération in physiological models (such as in lymphocytes) and pathological models (cancer). The rôle of the potassium channels in regulating the cell cycle was demonstrated in many cell types, whether physiological or pathological (cancerous lines or tumours) derived from human melanoma, lung cancer, lymphoma, mesothelioma, hepatocarcinoma, lymphocytes and monocytes (for review Pardo et al, J. Membr. Biol, 2005 ;205 : 115-124).

As used above, the term Kv indicates the potential-dependent family of potassium channels and comprises different subfamilies (Kvl., Kv2., Kv3. ...) among which the Kvl.l, Kvl. 2 and Kvl. 3... channels are to be found.

A Kv channel blocker dénotés a molécule that reduces or blocks the K⁺ ion flow through the channel.

As used herein, the term salts refers to the inorganic acid and base addition salts of the compounds of the présent invention. The salts are preferably pharmaceutically acceptable, i.e. they are non-toxic to

• 1 the patient to whom they are administered. The term pharmaceutically acceptable refers to molecular entities and compositions which do not resuit in any adverse or allergie effect or any other undesirable reaction when administered to an animal or human. When used herein, the term pharmaceutically acceptable excipient includes any diluent, adjuvant or excipient, such as preservative agents, filling agents, disintegrating, wetting, emulsifying, dispersing, antibacterial or antifungal agents, or furthermore agents allowing delay of absorption or intestinal and digestive résorption. Use of these media or vectors is well known to the art. Unless the agent is chemically incompatible with a diarylpyridazinone dérivative, its use in pharmaceutical compositions with the compounds according to the invention is envisaged. Within the context of the invention, the term treatment as used herein means preventing or inhibiting occurrence or progression of the disorder to which the term applies or indeed one or several symptoms of this disorder.

The subject of the présent invention is diarylpyridazinone dérivatives that block the potassium Kv channels (more specifically the Kv 1.5, Kv4.3 and Kv 11.1 channels) and use thereof for the treatment of humans.

These compounds correspond to the general formula

J wherein

Ri and R₂ simultaneously or îndependently represent one or several groups chosen from: halogen such as F, Br, Cl, linear or branched C1-C4 alkyl, hydroxy, linear or branched Ci-C₄ alkoxy, nitrile or arylsulfonamido the aryl of which is optionally substituted by a linear or branched Ci~C₄ alkyl group, as well as the different enantiomers and their mixtures in ail proportions, and their pharmaceutically acceptable salts.

Within the context of the présent invention, the aryl group désignâtes hydrocarbonated aromatic 5- or 6membered monocycles.

According to an embodiment of the invention, the compounds of general formula I are those for which:

Ri represents a hydroxy, methoxy or cyano group;

R₂ represents several groups chosen from: halogen such as F, Br, Cl, linear or branched Ci-C₄ alkyl, hydroxy, linear or branched Ci~C₄ alkoxy, nitrile;

as well as the different enantiomers and their mixtures in ail proportions, and their pharmaceutically acceptable salts.

According to another embodiment of the invention, the compounds of general formula I are those for which:

• 4

Ri represents a hydroxy group,

R2 represents several groups chosen from: halogen such as F, Cl, linear or branched C1-C4 alkyl, hydroxy, linear or branched C1-C4 alkoxy, nitrile; as well as the different enantiomers and their mixtures in ail proportions, and their pharmaceutically acceptable salts.

Ri represents a hydroxy group located in para position (position 4) on the phenyl which it substitutes, R2 represents several groups chosen from: Cl, methyl, hydroxy, methoxy, nitrile; as well as the different enantiomers and their mixtures in ail proportions, and their pharmaceutically acceptable salts.

The présent invention concerns the compounds of general formula I, characterised in that they are chosen from:xV * 4

I. 4,5-Bis-(4-hydroxy-phenyl)-2-(1-phenyl-ethyl)2H-pyridazin-3-one . 4,5-Bis-(4-hydroxy-phenyl)-2-( (S)-1-phenylethyl) -2H-pyridazin-3-one

3. 4,5-Bis-(4-hydroxy-phenyl)-2-((R)-1-phenylethyl) -2H-pyridazin-3-one

4. 2,2'-(6-oxo-l-(1-phenylethyl)-1,6dihydropyridazine-4,5-diyl) dibenzonitrile

5. 3,3'-(6-oxo-l-(1-phenylethyl)-1,6dihydropyridazine-4,5-diyl) dibenzonitrile

6. 4,5-Bis-(4-methoxy-phenyl)-2-(1-phenyl-ethyl)2H-pyridazin-3-one . N,N’-(3,3'-(6-oxo-l-(1-phenylethyl)-1,6dihydropyridazine-4,5-diyl)bis(3, 1- pheylee))bis(4methylbenzenesulfonamide)

8. 3-(5-(4-methoxyphenyl)-6-oxo-l-(1phenylethyl)-1,6-dihydropyridazin-4-yl) benzonitrile

9. 2-[5-(4-Methoxy-phenyl)-6-oxo-l-(1-phenylethyl) -1,6-dihydro-pyridazin- 4-yl]-benzonitrile

10. N-{3-[5-(3,4-Dimethyl-phenyl)-6-oxo-l -(1 phenyl-ethyl )-1,6-dihydropyridazin-4-yl]-phenyl}-4methyl-benzenesulfonamide

II. 4,5-Bis-(3,4-dichloro-phenyl)-2-(1-phenylethyl) -2H-pyridazin-3-one

* A

The présent invention also covers the different enantiomers of the compounds of general formula I, as well as their mixtures in ail proportions.

The mixtures of the enantiomers in ail proportions also include racemic mixtures.

The subject-matter of the invention likewise concerns the different enantiomers and their mixtures in ail proportions of the compounds of general formula I as well as the pharmaceutically acceptable salts.

The présent invention also covers the processes for chemical préparation of the compounds of general formula I as well as the different enantiomers and their mixtures in ail proportions.

The two enantiomers may be prepared enantioselectively from the (R)- or (S)-lphenylethanols respectively. Furthermore, based on the racemic, it is possible to obtain both enantiomers by préparative HPLC séparation on a chiral column (for example Chiralpack AD-H, eluent: heptane/EtOH/diethylamine).

The présent invention likewise concerns the compounds of general formula

I as well as different enantiomers and their mixtures in ail proportions and their pharmaceutically acceptable salts for use thereof as blockers of the potassium Kv channels and more specifically the Kv 1.5, Kv4.3 and Kv 11.1 channels.

The présent invention likewise concerns the compounds of general formula I as well as the different enantiomers and their mixtures in ail proportions and^

the pharmaceutically acceptable salts thereof for use thereof as a médicament.

The invention also concerns the compounds of general formula I as well as different enantiomers and their mixtures in ail proportions and their pharmaceutically acceptable salts for use thereof as a médicament intended for treatment and/or prévention of diseases requiring blockers of potassium Kv channels and more specifically the Kv 1.5, Kv4.3 and Kv 11.1 channels.

The invention also concerns the compounds of general formula I as well as the different enantiomers and their mixtures in ail proportions and the pharmaceutically acceptable salts thereof for their use as a medicine intended for treatment and/or prévention of diseases such as atrial fibrillation and auricular and/or ventricular cardiac arrhythmias, but also diseases in which the cell cycle, cell prolifération and régénération are modified (cancer, chronic inflammation).

The invention also covers the compositions characterised in that they contain as the active substance a compound of general formula I or one of the enantiomers thereof and their mixtures in ail proportions, or one of the pharmaceutically acceptable salts thereof.

The invention also concerns a pharmaceutical composition characterised in that it contains a compound of general formula I or one of the enantiomers/ ^J · 4 thereof and their mixtures in ail proportions or one of the pharmaceutically acceptable salts thereof in combination with any pharmaceutically acceptable excipient.

The pharmaceutical compositions according to the invention may be administered via the oral, sublingual, subcutaneous, intramuscular, intravenous, transdermal, local or rectal route. In this case, the active substance may be administered in unit forms of administration, in a mixture with conventional pharmaceutical carrier, to animais or humans.

Appropriate unit forms of administration comprise forms via the oral route such as tablets, capsules, powders, granules and oral solutions or suspensions, sublingual and buccal forms of administration, subcutaneous, topicai, intramuscular, intravenous, intranasal or intraocular forms of administration and rectal forms of administration. The appropriate formulations for the chosen form of administration are known to the person skilled in the art and are described for example in: Remington, The science and Practice of Pharmacy, 19th édition, 1995, Mack Publishing Company.

The dosages of the compounds of formula I in the compositions of the invention may be adjusted in order to obtain a quantity of active substance that is effective in order to obtain the desired therapeutic response for a composition spécifie to the method of administration. The effective dose of a compound according to the invention varies depending on a large number of parameters such as for example the selected

- . s route of administration, weight, âge, sex and nature of the disease in addition to the sensitivity of the person to be treated. Consequently, the optimum dosage needs to be determined by the specialist in the subject as a function of the parameters deemed relevant.

SYNTHESIS

The compounds of the présent invention may be synthesised using the synthetic routes described below or by using synthetic methods known to the person skilled in the art.

This method of synthesis of the compounds of general formula I (figure 1) is characterised in that a dibromo or dichloro pyridazinone of general formula II is condensed for which X represents either a chlorine atom or a bromine atom,

II

X with a dérivative of general formula III,

for which

- when A represents a halogen atom such as a chlorine or a bromine atom, a base such as CS2CO3 is used in a solvent such as dimethylformamide.

/ , ·

when A represents OH, Mitsunobu coupling conditions are used such as in presence of ethyl diethylazodicarboxylate and triphenylphosphine in a solvent such as THF. These conditions are in particular applicable to enantioselective synthesis of compounds of general formula I from the (R) or (S)-lphenylethanol.

The intermediate IV obtained

is then coupled (step 1) with a boron dérivative

for which Ri is as defined in the general formula and U represents

B(OH)2 or

in a mixture of solvents such as toluene/ethanol or water/acetonitrile or dioxane/water of a base such as sodium or potassium in the presence carbonate and a catalyst such as tetrakis(triphenylphosphine)palladium or PdCl₂/2PPh₃.

These operating conditions mainly lead to formation of compound VI and minimally resuit in formation of compound VII.

·* · * *

The intermediate VI is then reacted again (step

2) :

- either with the boron dérivative V under the coupling conditions described above, yielding compound VII.

- or with the boron dérivative VIII

VIII

for which

R₂ is as defined in

I and U is as defined above in the previously described for step compound IX.

the general formula coupling conditions order to yield the in

The intermediate and final compounds may, if desired, be purified according to one or several purification methods chosen from extraction, filtration, chromatography on silica gel, normal phase or reverse phase or chiral préparative HPLC and crystallisation.

The starting materials used in the processes described above are commercially available or are readily accessible to the person skilled in the art according to processes described in the literature.

The following examples illustrate the invention without limiting the scope thereof.

The elemental analyses and the mass and NMR spectra confirm the structures of the compounds.

EXAMPLES

A) INTERMEDIATES

Intermediates 1:

a) 4,5-dichloro-2-(1-phenylethyl)pyridazin-3(2H)one (la)

The 4,5-dichloropyridazin-3(2H)-one (20 g, 121 mmol) is placed in presence of 1-bromoethyl)benzene (33.7 g, 182 mmol) and césium carbonate (47.4 g, 145 mmol) in lOOmL of DMF at ambient température for 4h. Following concentration to dryness, the residue is taken up with water and is extracted using ethyl acetate. The organic layers are dried and subsequently concentrated to /-jT ' I dryness. The residue obtained is purified by flash chromatography on siiica (Petroleum ether-AcOEt: 95-5) .

31g of clear oil is obtained (yield 95%). TLC siiica gel 60 F 254 Merck, Petroleum ether-AcOEt: 90-10,

Rf=0.50.

b) 4,5-Dichloro-2-((S)-1-phenyl-ethyl)-2Hpyridazin-3-one (1b)

The 4,5-dichloropyridazin-3(2H)-one (1.35 g, 8.2 mmol) is placed in 30mL of THF in the presence of (R)-1-phenylethanol (1 g, 8.2 mmol) and triphenylphosphine (2.15 g, 8.2 mmol) to which ethyl diethylazodicarboxylate is added (1.71 g, 9.82 mmol. The reaction medium is stirred overnight at ambient température and subsequently concentrated to dryness. The residue is taken up with water and is extracted with dichloromethane on an SPE column (diatomaceous earth). The organic layers are concentrated to dryness and the residue obtained is purified by flash chromatography on siiica (0Η₂Ο1₂) . 2.1 g of yellow oil is isolated (yield 80%) . TLC siiica gel 60 F 254 Merck, CH₂Cl₂-MeOH :95-5, Rf=0.66.

c) 4,5-Dichloro-2-((R)-1-phenyl-ethyl)-2Hpyridazin-3-one (le)

« . * *

The intermediate 1 c (oil) is prepared from (S) —

1-phenylethanol according to the operating method described for the intermediate lb (77%). TLC silica gel

F 5 254 Merck, CH₂Cl₂-MeOH: 90-10, Rf=0.82.

B) COMPOUNDS ACCORDING TO THE INVENTION

Example_____1: 4,5-Bis-(4-hydroxy-phenyl)-2-(1phenyl-ethyl)-2H-pyridazin-3-one (1)

The compound 1 is prepared according to the following method of synthesis:

Step 1: the intermediate la (8.7 g, 32.3 mmol) is placed in presence of tetrakis(triphenylphosphine)palladium(0) (1.12 g,

0.97 mmol) and sodium carbonate (6.85 g, 64.7 mmol) in a mixture of 50 mL of toluene and 50 mL of éthanol and the mixture is heated to 80°C. 1.2 équivalent of 4hydroxyphenylboronic acid is added and the mixture is heated under reflux for 5h and 1.2 additional équivalent of 4-hydroxyphenylboronic acid is added and the reflux is maintained throughout the night. Following concentration to dryness, the residue is taken up with water and is extracted using AcOEt. After drying the organic layers and concentration to dryness, the residue obtained is purified by flash chromatography (CH₂C12-MeOH, gradient 100-0 to 97-3 over^ ¹ 1 ^J 4 min.). 0.7g of minority compound 1 is obtained and

8.2g of solid corresponding to the majority substituted mono product 4-chloro-5-(4-hydroxyphenyl)-2-(1phenylethyl)-pyridazin-3(2H)-one is obtained (yield:78%).

Step 2: this substituted mono product is reacted again under the conditions described for step 1 (2.4 équivalents of 4-hydroxyphenylboronic acid, reflux overnight). Following treatment of the reaction medium, the residue obtained is purified by flash chromatography (CH2C12-MeOH, gradient 100-0 to 98-2 over 20 min.). The residue is triturated in a mixture of diethylether-CH2C12~MeOH: 40-5-2 and the compound 1 (solid) obtained is isolated by filtration (7.2g, yield 78%) .

TLC silica gel 60 F 254 Merck, CH2C12-MeOH: 95-5, Rf=0.35. F=160°C

NMR ^XH (DMSO-d6) ppm: 9.56 (m, 2H), 8.02 (s, 1H), 7.39 (m, 5H), 6.96 (m, 4H), 6.63 (m, 4H), 6.24 (m,1 H), 1.72 (d, 3H).

MS (+ESI) m/z 385 (MH+)

Example 2 : 4,5-Bis-(4-hydroxy-phenyl)-2-((S)-1phenyl-ethyl)-2H-pyridazin-3-one (2)

¹ . ¹ *

Compound 2 is prepared according to the method of synthesis described for example 1 from the intermediate le (yield: 85%).

TLC silica gel 60 F 254 Merck, CH₂Cl₂-MeOH: 90-10,

Rf=0.60.

F=168°C

NMR ^XH (DMSO-d6) ppm: 9.70 (s, 1H) , 9.54 (s, IH) , 8.02 (s, IH) , 7.39 (m, 5H), 6.97 (m, 4H), 6.63 (m, 4H), 6.24 (m, 1 H) , 1.72 (d, 3H) .

MS (+ESI) m/z 385 (MH+) oicaïc (MeOH) = -256.5°

Chiral HPLC: Chiralpack column AD-H 250*4.6mm DAI, eluent (1 mL/min.): heptane/EtOH/diethylamine: 80/20/0.1 , rétention time: 8.92 min.

Example 3: 4,5-Bis-(4-hydroxy-phenyl)-2-((R)-lphenyl-ethyl)-2H-pyridazin-3-one (3)

HO

Compound 3 is prepared according to the method of synthesis described for example 1 from the intermediate lb (yield: 43%).

TLC silica gel 60 F 254 Merck, CH₂Cl₂-MeOH: 90-10,

Rf=0.60.

F=222°CX

NMR ^XH (DMSO-d6) ppm: 9.70 (s, 1H) , 9.54 (s, 1H) ,

8.02 (s, 1H), 7.39 (m, 5H), 6.97 (m, 4H), 6.63 (m, 4H),

6.24 (m,1 H), 1.72 (d, 3H).

MS (+ESI) m/z 385 (MH+) a_caic(MeOH)=272.2°

Chiral HPLC: Chiralpack column AD-H 250*4.6mm DAI, eluent (1 mL/min.): heptane/EtOH/diethylamine: 80/20/0.1 _t rétention time: 7.23 min.

Example 4 : 2,2'-(6-oxo-l-(1-phenylethyl)-1,6dihydropyridazine-4,5- diyl)dibenzonitrile (4)

Compound 4 is prepared from the intermediate la and

2-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2- yl)benzonitrile according to step 1 of the method of synthesis using PdC12/2PPh3, Na2CO₃ and a mixture of water/acetonitrile: 1/1. The minor product formed corresponds to compound 4 (yield: 3.4%).

TLC silica gel 60 F 254 Merck, CH2CI2, Rf=0.23.

F=200°C

NMR ^XH (DMSO-d6) ppm: 8,19 (s, 1H), 7.80 (d, 2H),

7.75 (d, 2H), 7.36 (m, 9H), 6.27 (q, 1H), 1.76 (d, 3H).

MS (+ESI) m/z 403 (MH+)xf * ♦ * i

Example 5: 3, 3 ' - (6-oxo-l-(1-phenylethyl)-1,6dihydropyridazine-4,5-diyl) dibenzonitrile (5)

Compound 5 is prepared from intermediate la and

3-cyanophenylboronic acid under the conditions described for example 4. The minor product formed (solid) corresponds to compound 4 (yield:7.4%).

TLC silica gel 60 F 254 Merck, CH₂C1₂, Rf=0.11.

F=202°C

NMR ²Η (DMSO-d6) ppm: 8.23 (s, 1H), 7.78 (m, 3H), 7.72 (s, 1H), 7.40 (m, 9H), 6.28 (q, 1H), 1.77 (d, 3H).

MS (+ESI) m/z 403 (MH+)

Example_____6: 4,5-Bis- (4-methoxy-phenyl) -2- (1phenyl-ethyl)-2H-pyridazin-3-one (6)

Compound 6 is prepared trom intermediate la and

4-methoxyphenylboronic acid under the conditions described for example tetrakis(triphenylphosphine)palladium(0),

K₂co₃ using and

• ι ¹ ί mixture of dioxane/water: 3/1. Compound 6 is isolated in solid form (yield: 71%).

TLC silica gel 60 F 254 Merck, Petroleum etherAcOEt:80-20, Rf=0.20.

NMR ^XH (CDCI3) ppm: 7.88 (s, 1H) , 7.53 (d, 2H) , 7.37-7.31 (m, 2H) , 7.30-7.26 (m, 1H) , 7.14-7.13 (d, 2H), 7.06-7.02 (d, 2H) , 6.80-6.75 (m, 4H) , 6.47-6.40 (m, 1H), 3.78 (s, 3H), 3.77 (s, 3H), 1.83 (s, 3H) .

MS (+ESI) m/z 413 (MH+)

Example 7 : N,N'-(3,3’-(6-oxo-l-(1-phenylethyl)-

1,6-dihydropyridazine-4,5-diyl)bis(3, 1- phenylene))bis(4-methylbenzenesulfonamide) (7) ' NH

0=8=0

Compound 7 is prepared from intermediate la and 4-methyl-N-(3-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-

2-yl)phenyl) benzenesulfonamide under the conditions described for example 6. Compound 7 is isolated in solid form (yield: 74%).

TLC silica gel 60 F 254 Merck, Petroleum etherAcOEt: 50-50, Rf=0.46.

• · ¹ t

	NMR ^XH (DMSO) ppm: 10.26 (s, 1H) , 10.14 (s, 1H) ,
7.92	(s,	1H), 7.53	(d, 4H), 7.42-7.25	(m, 9H), 7.08-
6.88	(m,	6H), 6.52	(dd, 2H), 6.26-6.18	(m, 1H) , 2.31
(s,	6H) ,	1.74 (d, 3H).
	MS	(+ESI) m/z	691 (MH+)

Example 8 :

phenylethyl)-1,6(8)

3-(5-(4-methoxyphenyl)-6-oxo-l-(1- dihydropyridazin-4-yl)benzonitrile

Compound 8 is prepared from intermediate la and 3-cyanophenylboronic acid according to step 1 of the method of synthesis using PdC12/2PPh₃, Na₂CO₃ and a mixture of water/acetonitrile: 1/1. The major product formed (1.96 g, 3-(5-chloro-6-oxo-l-(1-phenylethyl)-

1,6-dihydropyridazin-4-yl)benzonitrile, yield: 19%) is isolated and subsequently introduced into step 2 of the method of synthesis using 4-methoxyphenylboronic acid with tetrakis(triphenylphosphine)palladium(0), K2CO3 and a mixture of dioxane/water: 2/1. Compound 8 is isolated in solid form (yield: 62%).

TLC silica gel 60 F 254 Merck, Petroleum etherAcOEt: 50-50, Rf=0.53.

F=198°C

TLC silica gel 60 F 254 Merck, Petroleum etherAcOEt: 50-50, Rf=0.53.^ . < I

	NMR	³H (DMSO-d6)	ppm: 8.13	(s, 1H),	7.77	(m, 2H),
7.38	(m,	7H), 7.09 (d,	2H), 6.81	(d, 2H),	6.28	(q, 1H),
3.71	(s,	3H), 1.75 (d,	3H) .
	MS	(+ESI) m/z 408	(MH+)

Example 9: 2-[5-(4-Methoxy-phenyl)-6-oxo-l-(1phenyl-ethyl)-1,6-dihydro-pyridazin-4-yl]-benzonitrile (9)

Compound 9 is prepared from intermediate la and 2-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2“ yl) benzonitrile according to step 1 of the method of synthesis using PdC12/2PPh3, Na2CÛ3 and a mixture of water/acetonitrile: 1/1. The major product formed (1.5 g, 2-(5-chloro-6-oxo-l-(1-phenylethyl)-1, 6dihydropyridazin-4-yl) benzonitrile, yield: 16%) is isolated and subsequently introduced into step 2 of the method of synthesis with 4-methoxyphenylboronic acid using tetrakis(triphenylphosphine)palladium(O), K₂CO₃and a mixture of dioxane/water : 2/1. Compound 9 is isolated in solid form (yield: 71%).

TLC silica gel 60 F 254 Merck, Petroleum etherAcOEt: 70-30, Rf=0.45.

F=176°C

TLC silica gel 60 F 254 Merck, Petroleum etherAcOEt: 50-50, Rf=0.53.

I 4 l

	NMR	^XH (DMSO-d6)	ppm: 8.09	(s,	1H) ,	7.79	(d,	2H) ,
7.40	(m,	7H), 7.08 (d,	2H), 6.81	(d,	2H) ,	6.28	(q,	1H),
3.71	(s,	3H), 1.75 (d,	3H) .
	MS	(+ESI) m/z 408	(MH+)

Example 10: N-{3-[5-(3,4-Dimethyl-phenyl)-6-oxo1-(1-phenyl-ethyl)-1,6-dihydro-pyridazin-4-yl]-phenyl}-

4-methyl-benzenesulfonamide (10)

Compound 10 is prepared from intermediate la and 4-methyl-N-(4-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan2-yl)phenyl)benzenesulfonamide according to step 1 of the method of synthesis using PdC12/2PPh3, Na₂CO3 and a mixture of water/acetonitrile: 1/1. The major product formed (-N-(3-(5-chloro-6-oxo-l-(5g, 1-phenylethyl)-

1,6-dihydropyridazin-4-yl)phenyl)-4méthylbenzenesulfonamide, yield: 62%) is isolated and subsequently introduced into step 2 of the method of synthesis with 3,4-dimethylphénylboronic acid using tetrakis(triphenylphosphine)palladium(0), K₂CO₃ and a mixture of dioxane/water: 2/1. Compound 10 is isolated in solid form (yield: 67%).

TLC silica gel 60 F 254 Merck, CH₂Cl₂“MeOH; 97.52.5, Rf=0.65.^ • ♦* l

	NMR ^XH (DMSO) ppm	: 10	.24	(s, 1H), 7.92	(s,	1H)
7.54	(d, 2H), 7.41-7.26	(m,	7H)	, 7.10 (t, 1H),	7.04	(s
1H) ,	6.96-6.91 (m, 2H) ,	, 6-	88	(d, 1H), 6.72	(d,	1H)
6.62	(d, 1H), 6.27-6.20	(m,	1H)	, 2.34 (s, 3H),	2.15	(s
3H) ,	2.06 (s, 3H), 1.73	(d,	3H) .

MS (+ESI) m/z 550 (MH+)

Example 11: 4,5-Bis-(3,4-dichloro-phenyl)-2-(1phenyl-ethyl)-2H-pyridazin-3-one (11)

Compound 11 is prepared from intermediate la and 3,4-dichlorophenylboronic acid under the conditions described for example 1 using tetrakis(triphenylphosphine)palladium(0) , K2CO3 and a mixture of dioxane/water: 7/3. Compound 12 is isolated in solid form (yield: 54%).

F=92°C

TLC silica gel 60 F 254 Merck,

Petroleum etherAcOEt: 80-20, Rf=0.54.

NMR		(DMSO)	ppm:	8.19	(s, 1H),	7.64	(d,	1H) ,
7.61-7.57	(m,	2H) ,	7.54	(d,	1H), 7.44-	•7.26	(m,	SH) ,
7.13 (dd,	1H)	, 7.07	(dd,	1H) ,	6.30-6.22	(m,	1H) ,	1.75

(d, 3H)

MS (+ESI) m/z 491 (MH+)^ ♦ « * 4

C) PHARMACOLOGICAL ASSESSMENT

The pharmacological assessment of the compounds on the Kvl.5 potassium channel was performed in a

96well plate in

FLIPR technology by thallium ion measurement.

The HEK293 cells, stably transfected with the human isoform of the Kvl. 5 channels, are seeded

24h before expérimentation in

96-well plates (15

10⁶ cells/plate,

200 μΐ/well) polylysinated in the following culture medium:

DMEM,

10%

SVF,

Penicillin/Streptomycin,

G418 as the sélection antibiotic.

The expérimentation in

FLIPR is performed using the FLIPR Potassium Ion

Channel

Assay Kit) as indicated by the manufacturer (Molecular Devices).

Briefly, the culture medium is replaced by the solution containing the thallium marker for 90 min at 37°C. Following this step, the compounds to be tested are added to a final concentration of 10 μΜ in the well for 15 min at 37 °C. The basic fluorescence is subsequently read for 60 secs. The addition of a depolarising medium (20 mM of potassium and 3 mM of final thallium), opens the potassium channels and induces an increase in the fluorescence of the fluorophore thallium corresponding to an influx of thallium ions through the hKvl.5 channels. The measurement is performed 30 secs after injection of the depolarising solution. Application of 10 μΜ of DPO^' (Tocris, Kvl.5 channel blocker) allows normalisation of the fluorescence.

Table 1

Examples	% inhibition at 10 μΜ
BMS394136	99.6
1	100
2	100
3	43.3
4	54.9
5	93.6
6	94.2
7	54.9
8	88
9	60.1

BMS394136 is a Kvl.5 channel blocker under development at Bristol - Myers Squibb (Abstract, D. Xing et al. Circulation 2009, 120 (18S3): 2515).

The results obtained show that the compounds of general formula (I) block the Kvl.5 channel.

The compounds of general formula (I) may be used 10 as Kvl.5 channel blockers.^

D) ABBREVIATIONS

TLC Thin Layer Chromatography

DMF Dimethylformamide

DMSO Dimethylsulfoxide

DPO (2-isopropyl-5-méthyl-cyclohexyl) diphenylphosphine oxide

HPLC High Performance Liquid Chromatography

Rf Reference front

NMR Nuclear magnetic résonance

THF Tetrahydrofuran pZ

JUIN 2013

INET CAZENAVE sari Propriété Industrielle .P 500 YAOUNDE Cameroun

Tjél.22 21 32 89 - Fax: 22 20 64 14 mail: cabinetcazenave@iccnet.cni % · » ί

Claims

1. 4,5-Bis-(4-hydroxy-phenyl)-2-(1-phenyl-ethyl)2H-pyridazin-3-one

1) Compounds of general formula I:

wherein

Ri and R₂ simultaneously or independently represent one or several groups chosen from:

halogen such as F, Br, Cl, linear or branched C1-C4 alkyl, hydroxy, linear or branched Ci-C₄ alkoxy, nitrile or arylsulfonamido the aryl of which is optionally substituted by a linear or branched Ci~C₄ alkyl group, as well as the different enantiomers and their mixtures in ail proportions, and their pharmaceutically acceptable salts.

2. 4,5-Bis-(4-hydroxy-phenyl)-2-( (S)-1-phenylethyl) -2H-pyridazin-3-one

2) Compounds of general formula I according to claim 1) characterised in that

Ri represents a hydroxy, methoxy or cyano group;

R₂ represents several groups chosen from: halogen such as F, Br, Cl, linear or branched C1-C4 alkyl, hydroxy, linear or branched C1-C4 alkoxy, nitrile;

* · » I as well as the different enantiomers and their mixtures in ail proportions, and their pharmaceutically acceptable salts.

3. 4,5-Bis-(4-hydroxy-phenyl)-2-((R)-1-phenylethyl) -2H-pyridazin-3-one

3) Compounds of claims 1) to 2) of general formula I according any characterised in that:

Ri

R₂ such as represents a hydroxy group;

several groups chosen from: halogen hydroxy, represents

F, Cl, linear or branched C1-C4 alkyl, linear or branched Ci-C₄ alkoxy, nitrile;

4 r » * is subsequently coupled (step 1) with a boron dérivative V for which RI is as defined in the general formula

I and U représenta in a mixture of solvents such as toluene/ethanol or water/acetonitrile or dioxane/water in the presence of a base such as sodium or potassium carbonate and a catalyst such as tetrakis(triphenylphosphine)palladium or PdCl₂/2PPh₃;

in that one mainly obtains formation of the compound VI and minimally obtains formation of the compound VII;

the intermediate VI being subsequently reacted again (step 2):

either with the boron dérivative V in the coupling conditions previously described in order to yield the compound VII < * »

R1=R2

- or with the boron dérivative VIII

VIII for which R₂ is as defined in the general formula I and U is as defined above in the coupling conditions previously described for step 1 in order to yield the compound IX.

RI different from R2

4. 2,2'-(6-oxo-l-(1-phenylethyl)-1,6dihydropyridazine-4,5-diyl) dibenzonitrile

4 ) Compounds of claims 1) to 3) of general formula I according any characterised in that:

hydroxy group located in phenyl which

Ri represents position (position substitutes;

R₂ represents methyl, hydroxy, methoxy, nitrile;

• r » I as well as the different enantiomers and their mixtures in ail proportions and their pharmaceutically acceptable salts.

5 fibrillation, auricular and/or ventricular cardiac arrhythmias and of diseases in which the cell cycle and/or cell prolifération and/or régénération are impaired such as cancer or chronic inflammation.

11) Pharmaceutical composition comprising a

5. 3,3'-(6-oxo-l-(1-phenylethyl)-1,6dihydropyridazine-4,5-diyl) dibenzonitrile

5) Compounds of general formula I according to any of claims 1) to 4) characterised in that they are chosen from:

6) Process for préparation of the chemical compounds of general formula I according to any of daims 1) to 5) characterised in that a dibromo or dichloro pyridazinone of general formula II is condensed for which X represents either a chlorine atom or a bromine atom, with a dérivative of general formula III,

III for which:

- when A represents a halogen atom such as a chlorine atom or a bromine atom, a base such as CS2CO3 is used in a solvent such as dimethylformamide.

when A represents OH, Mitsunobu coupling conditions are used such as in presence of ethyl diethylazodicarboxylate and triphenylphosphine in a solvent such as THF;

the intermediate IV obtained

6. 4,5-Bis-(4-methoxy-phenyl)-2-(1-phenyl-ethyl)2H-pyridazin-3-one

7) Compounds of general formula I as defined according to any of daims 1) to 5) for use thereof as a medicine.

7. N,N'-(3,3'-(6-oxo-l-{1-phenylethyl)-1,6- dihydropyridazine-4,5-diyl)bis(3, 1- pheylee))bis(4methylbenzenesulfonamide)

8) Compounds according to claim 7 for use thereof as blockers of potassium channels and more specifically the Kv 1.5, Kv4.3 and Kv 11.1 channels.

8. 3-(5-(4-methoxyphenyl)-6-oxo-l-(1phenylethyl)-1,6-dihydropyridazin-4-yl) -benzonitrile

9) Compounds according to claim 7 for use thereof as a medicine intended for treatment and/or prévention of diseases requiring blockers of potassium channels <

and more specifically the Kv 1.5, Kv4.3 and Kv 11.1 channels. 10) Compounds according to claim 7 for use thereof in treatment and/or prévention of atrial

9. 2-[5-(4-Methoxy-phenyl)-6-oxo-l-(1-phenylethyl) -1, 6-dihydro-pyridazin-4-yl] -benzonitrile^ r ♦ I

10. N-{3-[5-(3,4-Dimethyl-phenyl)-6-oxo-l-(1phenyl-ethyl)-1,6-dihydro- pyridazin-4-yl]-phenyl}-4methyl-benzenesulfonamide

11. 4,5-Bis-(3,4-dichloro-phenyl)-2-(1-phenylethyl)-2H-pyridazin-3-one

10 compound of general formula I according to any of daims 1) to 5) in combination with at least one pharmaceutically acceptable excipient.