Acylation of spiro(1-pyrazoline-3,1?-cyclopropanes) to form 1-acyl-3-(2-chloroethyl)-2-pyrazolines and transformation of bicyclic 2-pyrazolines into 1,4,5,6-tetrahydropyridazines
作者:Yu. V. Tomilov、G. P. Okonnishnikova、E. V. Shulishov、O. M. Nefedov
DOI:10.1007/bf00696715
日期:1995.11
Strained polycyclic spiro(1-pyrazoline-3,1'-cyclopropanes) react with acetyl or benzoyl chlorides at 0-15 degrees C regioselectively to give in high yields corresponding 1-acyl-3-(2-chloroethyl)-2-pyrazolines. Under the same conditions 6-ethenyl-4,5-diazaspiro[2,4] hept-4-ene gives a mixture of two pyrazolines resulting from the acyl group attack directed at different nitrogen atoms. Bicyclic pyrazolines-2 obtained by acylation of the cycloaddition products of diazocyclopropane with 3,3-disubstituted cyclopropenes transform under the action of hydrogen chloride to 1,4,5,6-tetrahydropyridazines in high yields.