Tetrahedron

Hypervalent iodine oxidation of 5-substituted and 4, 5-disubstituted pyrazol-3 (2H)-ones: A facile synthesis of methyl-2-alkynoates and methyl 2, 3-alkadienoates

RM Moriarty, RK Vaid, VT Ravikumar, TE Hopkins…

Index: Moriarty, R. M.; Vaid, R. K.; Ravikumar, V. T.; Hopkins, T. E.; Farid, P. Tetrahedron, 1989 , vol. 45, # 6 p. 1605 - 1610

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Citation Number: 14

Abstract

Hypervalent iodine oxidation of various 5-substituted pyrazol-3 (2H)-ones (1a-h) with iodobenzene diacetate or iodosobenzene in methanol results in fragmentative loss of molecular dinitrogen to yield methyl 2-alkynoates (2a-h). However, 5-methyl-4-substituted pyrazol-3 (2H)-ones (3a-d) under similar conditions yield methyl 2, 3-allenic esters (4a-d). Methyl 2, 3-cycloalkadienoates (6a-e) are obtained by the oxidative cleavage of 4, 5- ...