Patent ID: 7812174

Claim:
A method of preparing a compound of formula I: which comprises: contacting a compound of formula II: with a compound of formula III: under conditions sufficient for the formation of a mixture of E and Z isomers of a compound of formula I; and contacting the mixture of E and Z isomers with a strong acid; wherein: X is optionally substituted alkyl; R 1 is optionally substituted alkyl; R 2 is hydrogen, halogen, nitrile, or optionally substituted alkyl, aryl, alkylaryl, arylalkyl, heteroalkyl, heterocycle, alkylheterocycle, or heterocyclealkyl; and R 3 is hydrogen or optionally substituted alkyl, aryl, alkylaryl, arylalkyl, heteroalkyl, heterocycle, alkylheterocycle, or heterocyclealkyl.