1-(Cyanoacetyl)-3,5-dimethylpyrazole as Active Methylene Compound in Hantzsch-Type Pyridine Synthesis: A Convenient and Highly Effective Approach to 3,5-Dicyano-4-(het)aryl-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates

Reaction of 1-(cyanoacetyl)-3,5-dimethylpyrazole with (E)-2-cyano-3-(het)arylprop-2-enethioamides was used for the synthesis of N-methylmorpholinium 3,5-dicyano-4-(het)aryl-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates for the first time. The latter were also obtained in a multicomponent one-pot mode via the condensation of cyanothioacetamide with corresponding aldehydes and above 1-cyanoacetylpyrazole in the presence of N-methylmorpholine under mild conditions. Thiolates 1 exist as a pair of cis/trans-diastereomers in different ratios (from 3:4 to 2:1).