| abstract |
A process for the preparation of a compound having the structure of Formula (I) wherein A, R1, R2, R3, Y and Z are as defined in the disclosure. The process includes reacting a heterocyclic amine with a monoaldehyde or a dialdehyde in a pH range of from about 8 to 14 and then quaternizing the so-reacted heterocyclic amine with an alkylating agent at a pH of not less than about 2. The use of a pH control substantially prevents formation of an undesirable protonated intermediate. |