Patent ID: 7655650

Claim:
A process for the preparation of a compound having the general formula (I) wherein: A is a pyridyl, 1-oxidobyridinio or thiazolyl group, in which A is unsubstituted or mono- or disubstituted by substituents selected from the group consisting of halogen and C 1 -C 3 alkyl; R is hydrogen, C 1 -C 6 alkyl, phenyl-C 1 -C 4 alkyl, C 3 -C 6 cycloalkyl, C 2 -C 6 alkenyl or C 2 -C 6 alkynyl; and X is N—NO 2 or N—CN, wherein said process comprises: (A) reacting a compound of formula (II) or a salt or tautomer thereof, with formaldehyde or paraformaldehyde at a temperature of between 0° C. and 180° C. wherein: R 1 is hydrogen or A—CH 2 ; and A, R and X are as defined above; and (B) when R 1 is hydrogen in step A, further reacting the product from step A with a compound having the Formula (V) A-CH 2 —Y (V) wherein: A, is as defined in Formula (I); and Y is a leaving group thereby to form a compound of Formula (I), or a tautomer thereof, in each case in free form or in salt form.