Collect. Czech. Chem. Commun. 1987, 52, 761-765

Conversion of thioacetamides, acetamides, and acetonitriles into trimethinium salts under Vilsmeier conditions

Jürgen Liebschera, Alexander Knolla, Horst Hartmannb and Sabine Andersb

a Department of Chemistry, Humboldt University Berlin, 1040 Berlin, G.D.R.
b Department of Chemistry, Technical University Dresden, 8027 Dresden, G.D.R.


Thioacetamides and N-(3-aminothioacryloyl)formamidines can be transformed to trimethinium salts by the reaction with formamide chlorides. The same products are formed by a modified Vilsmeier-Haack-Arnold reaction of acetamides or acetonitriles. The latter transformations can also be performed in two steps by the isolation of intermediate 2-aza-3-chlorpentamethinium salts.