Synthesis of 2-Oxazolone-4-carboxylates from 3-Nosyloxy-and 3-Bromo-2-ketoesters

…, RV Hoffman, MC Johnson

Index: Okonya, John F.; Hoffman, Robert V.; Johnson, M. Catherine Journal of Organic Chemistry, 2002 , vol. 67, # 4 p. 1102 - 1108

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Citation Number: 33

Abstract

New methods for the synthesis of 2-oxazolone-4-carboxylates from 3-nosyloxy-and 3-bromo- 2-ketoesters are described. Condensation of 3-nosyloxy-2-ketoesters with methyl carbamate in refluxing toluene in the presence of p-TSA provided 2-oxazolone-4-carboxylates in good yields (41-80%). Alternatively, bromination of α-ketoesters with CuBr2 provided 3-bromo-2- ketoesters which condensed with methyl carbamate in the presence of p-TSA and AgOTf ...