R. Duthaler
Jul 27, 1983
Citations
0
Influential Citations
12
Citations
Journal
Helvetica Chimica Acta
Abstract
Methyl 4-nitro-3-oxobutyrate (1) is prepared by substitution of 4-bromo- and 4-iodo-3-oxobutyrate enol ether or enol acetate derivatives with nitrite and deprotection of the keto function (Schemes 2 and 3). A much more convenient access to 1 is, however, the nitration of acetoacetate dianion with alkyl nitrates (Scheme 4). Compound 1 is stable and storable, and can be handled safely. Its use in cyclocondensations is established by the reaction with acetylacetone (Scheme 5), affording 4,6-dimethyl-3-nitrosalicylate 48 in 70% yield. The halogen-substitution method for the synthesis of 1 gives also access to the crystalline (E)-enol ether 18 of 1, as well as to its dimethyl acetal 25, (Z)-enol acetate 32, and (E)-enol acetate 33. The 3-substituted 4-bromobutenoates 15, 16 and 26 have been prepared from 4-bromo-3-oxobutyrate 12, a useful alternative to existing methods applying N-bromo-succinimide.