Patent ID: 7145035

Claim:
A method for preparing a compound of Formula V wherein K is, together with the two contiguous linking carbon atoms, a phenyl ring, a 5- or 6-membered heteroaromatic ring or an aromatic 8-, 9- or 10-membered fused carbobicyclic or heterobicyclic ring system wherein each ring or ring system is optionally substituted; R 1 is H, C 1 to C 4 alkyl or CO 2 R 3 ; R 2 is H or C 1 to C 4 alkyl; R 3 is C 1 to C 4 alkyl; and R 4 is CHR 1 R 2 ; the method comprising contacting a compound of Formula III, wherein A is NH and K is as defined for Formula V, with a compound of Formula IV R 1 R 2 CHS(O)R 4 IV wherein R 4 is CHR 1 R 2 and R 1 and R 2 are as defined for Formula V, in dichloromethane as an inert solvent and in the presence of sulfur trioxide as an activating agent to form a reaction product, and washing the reaction product in the inert solvent with an aqueous solution of a base to form the compound of Formula V.