1-Acylpyrazoles reacted with amines having a tiny substituent to affor
d the corresponding amides. The aminolysis with bulky amines was contr
olled to be retarded by the steric factors. Due to this steric interac
tion, the stereoselective aminolysis was observed. This selectivity of
aminolysis should increase the utility of pyrazoles as auxiliary comp
ounds in the synthetic loop.