Patent ID: 7393962

Claim:
A process for the preparation of a compound of formula (I): wherein R 1 is C 1-6 alkyl; R 2 and R 3 are, independently, C 1-6 alkyl; and R 4 is C 1-6 alkyl or benzyl (wherein the phenyl ring of benzyl is optionally substituted by cyano, C 1-4 alkyl, C 1-4 alkoxy, CF 3 or OCF 3 ); the process comprising reacting a compound of formula (II): wherein R 2 , R 3 and R 4 are as defined above, with an alkoxide base; and reacting the product so formed with R 1 OC(O)CH 2 X, wherein R 1 is as defined above and X is chloro, bromo or iodo; wherein the process is carried out in a suitable solvent at a temperature in the range −40° C. to −5° C.; and wherein at least 0.2 moles of the compound of formula (II) are used in the process.