Key points are not available for this paper at this time.
Two general protocols are developed for the regioselective synthesis of 1,3,5-tri- and 1,3,4,5-tetrasubstituted pyrazoles by the reaction of electron-deficient N-arylhydrazones with nitroolefins. Studies on the stereochemistry of the key pyrazolidine intermediate suggest a stepwise cycloaddition mechanism.
Deng et al. (2008) studied this question.