Studies on mesoionic compounds. Part 11. Alkylation of 5-acylamino-1,2,3-thiadiazoles

The alkylations of 5-acylamino-1,2,3-thiadiazoles (4) have been investigated; the N-3 position is preferably alkylated forming new mesoionic heterocycles (5) and (10). The mesoionic 1,2,3-thiadiazolium-5-alkoxy- and -5-aryloxy-carbonylaminides are converted into the corresponding salts of the 5-imine derivatives (11) by hydrolysis with hydrochloric acid.