A facile one-pot procedure for the synthesis of pyrazole-5-carboxylates by 1,3-dipolar cycloaddition of ethyl diazoacetate is described. Cycloadditions with alpha-methylene carbonyl compounds utilizing 1,8-diazabicyclo[5.4.0]undec-7-ene as base and acetonitrile as solvent provide pyrazoles with excellent regioselectivity and good yields. The reaction was found to proceed by a domino 1,3-dipolar cycloaddition-water elimination.
New one-pot synthesis of pyrazole-5-carboxylates by 1,3-dipole cycloadditions of ethyl diazoacetate with α-methylene carbonyl compunds
GIOIELLO, ANTIMO;PELLICCIARI, Roberto
2009
Abstract
A facile one-pot procedure for the synthesis of pyrazole-5-carboxylates by 1,3-dipolar cycloaddition of ethyl diazoacetate is described. Cycloadditions with alpha-methylene carbonyl compounds utilizing 1,8-diazabicyclo[5.4.0]undec-7-ene as base and acetonitrile as solvent provide pyrazoles with excellent regioselectivity and good yields. The reaction was found to proceed by a domino 1,3-dipolar cycloaddition-water elimination.File in questo prodotto:
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