Process for resolving aimines that are useful for the treatment of disorders associated with insulin resistance syndrome

Process for resolving a racemic compound of the formula (1) below:

• in which:
• R1, R2, R3 and R4 are chosen independently from the following groups:
• H;
• alkyl (C1-C20) optionally substituted by halogen, alkyl (C1-C5) or alkoxy (C1-C5), cycloalkyl (C3-C8);
• alkylene (C2-C20) optionally substituted by halogen, alkyl (C1-C5) or alkoxy (C1-C5);
• alkyne (C2-C20) optionally substituted by halogen, alkyl (C1-C5) or alkoxy (C1-C5);
• cycloalkyl (C3-C8) optionally substituted by alkyl (C1-C5) or alkoxy (C1-C5);
• heterocycloalkyl (C3-C8) bearing one or more hetero atoms chosen from N, O and S and optionally substituted by alkyl (C1-C5) or alkoxy (C1-C5);
• aryl (C6-C14) alkyl (C1-C20) optionally substituted by amino, hydroxyl, thio, halogen, alkyl (C1-C5), alkoxy (C1-C5), alkylthio (C1-C5), alkylamino (C1-C5), aryl (C6-C14) oxy, aryl (C6-C14) alkoxy (C1-C5), cyano, trifluoromethyl, carboxyl, carboxymethyl or carboxyethyl;
• aryl (C6-C14) optionally substituted by amino, hydroxyl, thio, halogen, alkyl (C1-C5), alkoxy (C1-C5), alkylthio (C1-C5), alkylamino (C1-C5), aryl (C6-C14) oxy, aryl (C6-C14) alkoxy (C1-C5), cyano, trifluoromethyl, carboxyl, carboxymethyl or carboxyethyl;
• or
• heteroaryl (C1-C13) bearing one or more hetero atoms chosen from N, O and S and optionally substituted by amino, hydroxyl, thio, halo gen, alkyl (C1-C5), alkoxy (C1-C5), alkylthio (C1-C5), alkylamino (C1-C5), aryl (C6-C14) oxy, aryl (C6-C14) alkoxy (C1-C5), cyano, trifluoromethyl, carboxyl, carboxymethyl or carboxyethyl;
• R1 and R2, on the one hand, and R3 and R4, on the other hand, possibly forming with the nitrogen atom an n-membered ring (n between 3 and 8) optionally comprising one or more hetero atoms chosen from N, O and S and possibly being substituted by one or more of the following groups:
• amino, hydroxyl, thio, halogen, alkyl (C1-C5), alkoxy (C1-C5), alkylthio (C1-C5), alkylamino (C1-C5), aryl (C6-C14) oxy, aryl (C6-C14) alkoxy (C1-C5), cyano, trifluoromethyl, carboxyl, carboxymethyl or carboxyethyl;
• R6 is chosen from the following groups:
• alkyl (C1-C20) optionally substituted by amino, hydroxyl, thio, halogen, alkyl (C1-C5), alkoxy (C1-C5), alkylthio (C1-C5), alkylamino (C1-C5), aryl (C6-C14) oxy, aryl (C6-C14) alkoxy (C1-C5), cyano, trifluoromethyl, carboxyl, carboxymethyl or carboxyethyl;
• alkylene (C2-C20) optionally substituted by amino, hydroxyl, thio, halogen, alkyl (C1-C5), alkoxy (C1-C5), alkylthio (C1-C5), alkylamino (C1-C5), aryl (C6-C14) oxy, aryl (C6-C14) alkoxy (C1-C5), cyano, trifluoromethyl, carboxyl, carboxymethyl or carboxyethyl;
• alkyne (C2-C20) optionally substituted by amino, hydroxyl, thio, halogen, alkyl (C1-C5), alkoxy (C1-C5), alkylthio (C1-C5), alkylamino (C1-C5), aryl (C6-C14) oxy, aryl (C6-C14) alkoxy (C1-C5), cyano, trifluoromethyl, carboxyl, carboxymethyl or carboxyethyl;
• cycloalkyl (C3-C8) optionally substituted by amino, hydroxyl, thio, halogen, alkyl (C1-C5), alkoxy (C1-C5), alkylthio (C1-C5), alkylamino (C1-C5), aryl (C6-C14) oxy, aryl (C6-C14) alkoxy (C1-C5), cyano, trifluoromethyl, carboxyl, carboxymethyl or carboxyethyl;
• heterocycloalkyl (C3-C8) bearing one or more hetero atoms chosen from N, O and S and optionally substituted by amino, hydroxyl, thio, halogen, alkyl (C1-C5), alkoxy (C1-C5), alkylthio (C1-C5), alkylamino (C1-C5), aryl (C6-C14) oxy, aryl (C6-C14) alkoxy (C1-C5), cyano, trifluoromethyl, carboxyl, carboxymethyl or carboxyethyl;
• aryl (C6-C14) optionally substituted by amino, hydroxyl, thio, halogen, alkyl (C1-C5), alkoxy (C1-C5), alkylthio (C1-C5), alkylamino (C1-C5), aryl (C6-C14) oxy, aryl (C6-C14) alkoxy (C1-C5), cyano, trifluoromethyl, carboxyl, carboxymethyl or carboxyethyl;
• heteroaryl (C1-C13) bearing one or more hetero atoms chosen from N, O and S and optionally substituted by amino, hydroxyl, thio, halogen, alkyl (C1-C5), alkoxy (C1-C5), alkylthio (C1-C5), alkylamino (C1-C5), aryl (C6-C14) oxy, aryl (C6-C14) alkoxy (C1-C5), cyano, trifluoromethyl, carboxyl, carboxymethyl or carboxyethyl;
• or aryl (C6-C14) alkyl (C1-C5) optionally substituted by amino, hydroxyl, thio, halogen, alkyl (C1-C5), alkoxy (C1-C5), alkylthio (C1-C5), alkylamino (C1-C5), aryl (C6-C14) oxy, aryl (C6-C14) alkoxy (C1-C5), cyano, trifluoromethyl, carboxyl, carboxymethyl or carboxyethyl;
• comprising the steps consisting in:
• a) reacting the racemic compound of structure (I) with a chiral reagent to form a corresponding diastereoisomeric salt;
• and
• b) purifying the diastereoisomeric salt thus obtained;
• c) releasing the diastereoisomeric salt as one of the two enantiomers of the formula (I) in the form of a pharmaceutically acceptable salt.