Patent ID: 8519176

Claim:
A process of preparing a compound of formula (I) or a salt thereof, wherein R 1 is (C 1-6 ) alkyl, or (C 3-12 )cycloalkyl; R 2 , R 3 , and R 4 are each independently selected from H, F, Cl, CF 3 , CN, —OH, —NH 2 , (C 1-6 ) alkyl, (C 3-12 )cycloalkyl, —O—(C 1-6 )alkyl, —NH(C 1-6 )alkyl, —NH(C 3-12 )cycloalkyl, (C 3-12 )cycloalkyl) and —N((C 1-6 )alkyl) 2 ; wherein each of R 1 to R 4 is optionally substituted by one or more substituents selected from H, F, Cl, CF 3 , OXO, CF 3 , CN, (C 1-4 alkyl, (C 3-12 )cycloalkyl, —OH, —SH, —O(C 1-6 ) alkyl, —S(C 1-6 ) alkyl, —NH 2 , —NH(C 1-6 ) alkyl, aryl and heteroaryl; comprising: Step A: converting a compound of formula (II) to a compound of formula (III) according to reaction scheme 1: wherein the compound of Formula (I) is reacted with a suitable amount of potassium trimethylsilanolate (TMSOK) in the presence of a suitable solvent at a suitable reaction temperature for a suitable reaction time to provide the compound of formula (III), wherein said compound of formula (III) is obtained via a suitable isolation procedure; Step B: converting the compound of formula (III) to a compound of formula (IV) according to reaction scheme 2: wherein the compound of formula (III) is reacted with a suitable amount of oxalyl chloride in the presence of a suitable solvent and at a suitable reaction temperature for a suitable reaction time to form an acid chloride intermediate; and then said acid chloride intermediate is reacted with a suitable amount of alcohol at a suitable reaction temperature for a suitable reaction time to provide the compound of formula (IV), wherein said compound of formula (IV) is obtained via a suitable isolation procedure; and Step C: converting the compound for formula (IV) to a compound of formula (I) according to reaction scheme 3: wherein the compound of formula (IV) is hydrogenated in the presence of a suitable amount of a suitable catalyst, a suitable solvent and at a suitable reaction temperature to provide a compound of formula (I), wherein said compound of formula (I) is obtained via a suitable isolation procedure.