US EPA

7432482 

Journal Article 

Synthesis of 2-oxazolone-4-carboxylates from 3-nosyloxy- and 3-bromo-2-ketoesters 

Okonya, JF; Hoffman, RV; Johnson, MC; , 

2002 

Yes 

Journal of Organic Chemistry
ISSN: 0022-3263
EISSN: 1520-6904 

AMER CHEMICAL SOC 

WASHINGTON 

67 

4 

1102-1108 

English 

11846650 

10.1021/jo010630z 

WOS:000173901700008 

https://pubs.acs.org/doi/10.1021/jo010630z
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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 alpha-ketoesters with CuBr2 provided 3-bromo-2-ketoesters which condensed with methyl carbamate in the presence of p-TSA and AgOTf under similar conditions to provide 2-oxazolone-4-carboxylates in comparable yields (30-79%). The 2-oxazolone-4-carboxylates bear functionality that can be elaborated to a variety of potentially useful compounds. For example, some of these heterocycles were readily N-acylated, reduced to alcohols, or saponified and coupled with amino acids. 

Bromination; Alcohols; Amino acids; Bromine compounds; Condensation; Esters; Toluene; Synthesis (chemical); alcohol derivative; amino acid derivative; bromine derivative; carbamic acid methyl ester; carboxylic acid derivative; ester derivative; ketone derivative; oxazole derivative; toluene; article; bromination; polymerization; reaction analysis; reduction; saponification; stereochemistry; synthesis