Pyrazoles were prepared in excellent yields via solventless condensation of various 1,3-diketones (R¹COCHXCOCH3, R¹ = Me, Ph; X = H, Me, Cl) and hydrazines, acylhydrazines or sulfonyl hydrazines in the presence of a catalytic amount of Sc(OTf)3 at room temperature. Additionally, the catalyst could be recovered easily after the reactions and reused without evident loss in activity.
scandium(III) triflate; pyrazoles; 1,3-diketones; hydrazines; hydrazides; solvent-free
