Studies of formal [1, 5]-sigmatropic thermal rearrangements of dimethyl 3-alkyl-3-methyl-3H-pyrazole-4, 5-dicarboxylates and dimethyl 4-alkyl-5-methyl-4H-pyrazole-3, …

EA Jefferson, J Warkentin

Index: Jefferson, Elizabeth A.; Warkentin, John Journal of the American Chemical Society, 1992 , vol. 114, # 16 p. 6318 - 6325

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Citation Number: 20

Abstract

Abstract: Studies of the thermal rearrangements of 3H-pyrazoles, lh-e, in benzene/toluene, chloroform, and methanol solvents are described. The mechanism for rearrangement appears to be two-step, involving discrete ion-pair intermediates. Large rate enhancements for these rearrangements in methanol and cation trapping by methanol are consistent with the proposed mechanism. Observed rate constants for the rearrangements of 3H- ...