Nuclear magnetic resonance study of addition-cyclization involving ethyl thioacetoacetate and α-nucleophiles

…, S Basu, L Copp, V Malatesta

Index: Cocivera, Michael; Basu, Soumen; Copp, Leslie; Malatesta, Vincenzo Canadian Journal of Chemistry, 1981 , vol. 59, p. 629 - 634

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Abstract

Addition of NH2NH2 or NH2OH to ethyl thioacetoacetate to form the corresponding cyclic product, 3-methylpyrazol-5-one or 3-methylisoxazol-5-one proceeds via cyclization of the carbinolamine formed by addition to the β-keto carbon, ie, cyclization is faster than dehydration of the carbinolamine to form the imine. In contrast the corresponding carbinolamine derived from ethylacetoacetate undergoes dehydration faster than ...