Patent ID: 7253291

Claim:
A process for preparing a compound of Formula I: wherein: R is hydrogen, C 1-2 alkyl, halogen, or C 1-2 alkoxy; R 1 is hydrogen, C 1-6 alkyl, C 2-6 alkenyl, or C 2-6 alkynyl; and R 2 is C 1-6 alkyl, C 2-6 alkenyl, or C 2-6 alkynyl; comprising a) reacting a compound of Formula II: wherein R is as defined above, with a compound of Formula III: wherein R 1 and R 2 are as defined above, in the presence of a diazodicarboxylate having Formula IV: wherein each R 3 is, independently, C 1-6 alkyl; and in the presence of a triarylphosphine of Formula V: P(Ar) 3 V wherein each Ar is phenyl optionally substituted with 1-3 substituents independently selected from CH 3 , OCH 3 and halogen; and in the presence of a solvent having Formula VI: Ar′ VI wherein Ar′ is phenyl optionally substituted with 1, 2 or 3 methyl groups; to form said compound of Formula I; and b) precipitating said compound of Formula I from the reaction mixture by adding one or more alcohols to the reaction mixture, after said reacting of step a).