Acetic Anhydride → 5,6-Dichloro-2-methyl[1,3]thiazolo[4,5-b]pyrazine

Participants

Reaction Conditions

Reaction Steps

A mixture of 9.8 g. (0.05 mol.) of 2-amino-5,6-dichloro-3-mercaptopyrazine and 5.1 g. (0.05 mol.) of acetic anhydride in 100 ml. of xylene was heated at 110° C. for 1 hour. The reaction mixture was cooled, another 5.1 g. of acetic anhydride was added and heating at 110° C. was continued for 15 hours. The reaction mixture was concentrated under reduced pressure to give a dark oil, which solidified under isopropanol-hexane while cooling in ice. The dark solid was purified by sublimation to give 7 g. (64% yield) of white solid, m.p. 58°-60° C.

Provenance & Evidence