255. Construction of Highly Substituted Nitroaromatic Systems by Cyclocondensation. Part II. Conversion of 4-Nitr-3-oxobutyrate to 3-Nitrosalicylates

Article abstract of DOI:10.1002/hlca.19830660821

The base-catalyzed reaction of 4-nitro-3-oxobutyrate (6) with acetylacetone (8), formylacetone (13), formylcyclohexanone (31), 2,4-dioxopentanoates 39 and 40, and 2,4,6-heptanetrione (2) affords substituted 3-nitrosalicylates, products of a double aldol condensation.With unsymmetrical dicarbonyl compounds both regioisomers are formed.High selectivity was found in the case of β-keto-aldehydes 13 and 31 with preferred addition of the NO2-substituted carbon to the aldehyde carbonyl.The major products of these cyclocondensations, which are isolated in yields ranging from 20 percent to 80 percent, are all new compounds.Less successful are the conversions with β-alkoxy- and β-chloro-vinyl ketones (23, 25, and 26), and with alkinone 24, where the condensation products are formed in very low yield.