Аннотация:
[3 + 2] Cycloaddition of 1-arylmethylidene-3-oxopyrazolidin-1-ium-2-ides (stable azomethine imines) to (arylmethylidene)malononitriles proceeds regio- and stereoselectively to afford 1,3-diaryl-5-oxotetrahydropyrazolo[1,2-a]pyrazole-2-carbonitriles that proved resistant to azomethine imines metathesis.