PYRAZOLINES: IV. REARRANGEMENT OF ALKYL GROUPS DURING THE PYROLYSIS OF 4,4-DIALKYL-3-CYANO-3-CARBOMETHOXY-Δ¹-PYRAZOLINES

Abstract

A number of 4,4-dialkyl-3-cyano-3-carbomethoxy-Δ 1 -pyrazolines have been synthesized. Pyrolysis of these pyrazolines yielded cyclopropane and olefin products. The formation of olefin products by rearrangement of an alkyl group from C 4 to C 5 of the pyrazoline system suggests that positive charge is developed on C 5 in the transition state. Ionic character in the transition state was also indicated by the fact that the rate of pyrolysis is faster in polar than in nonpolar solvents.