Patent ID: 7214797

Claim:
A process for preparing a compound according to formula 1, the process comprising in a first step: reacting a compound of formula 2 with a compound of formula 3 wherein R′ denotes chlorine or a C 1 –C 4 -alkyloxy group, to produce an intermediate compound of formula 4 and in a second step reacting the intermediate compound of formula 4 with a compound of the formula R 2 —X, wherein A is a group selected from R is methyl, ethyl, —CF 3 , or —CHF 2 ; R 1 and R 2 , which are identical or different, are each C 1 –C 3 -alkyl; R 3 , R 4 , R 3′ and R 4′ which may be identical or different denote hydrogen, —C 1 –C 4 -alkyl, —C 1 –C 4 -alkyloxy, hydroxy, —CF 3 , —CHF 2 , CN, NO 2 or halogen; and X − is an anion with a single negative charge.