Studies on Mesoionic Compounds. II. Synthesis of N-Acyl Derivatives of 3-Dialkylaminosydnonimines

Abstract

A number of N-acyl and N-nitroso-3-dialkylaminosydnonimines (II) were synthesized by various acylating methods. In some cases, the acylation with activated esters, mixed anhydrides or dicyclohexylcarbodiimide was found to be more favorable. The reactivities of these derivatives towards acids and alkalis were investigated. Trifluoroacetyl (II-6) and formyl (II-1) compounds were easily deacylated in varuous conditions. Methylation took place at the acylated imino nitrogen of N-ethoxycarbonyl compound to give the quaternary salt (II-18). N-Acetyl compound (II-2) was compared with its 3-alkyl analog in the physicochemical properties ; its pKa values reveals that the morpholino group has little effect on the basicity of the compound.