Base-catalyzed rearrangement of 2H-indazoles 1-oxides, prepared by tandem carbon-carbon followed by nitrogen-nitrogen bond formations from easily accessible N-alkyl-2-nitro-N-(2-oxo-2-aryl-ethyl)-benzenesulfonamides using glycine, 2-nitrobenzenesulfonyl chlorides and bromo ketones/acetates, yielded high purity quinazolines.

The efficient solid-phase synthesis of 3-hydroxy-2,7-disubstituted-6-nitroquinolin-4(1H)-ones using Rink amide resin is described. Synthesis starts from immobilized 4-chloro-5-nitroanthranilic acid which, after the nucleophilic replacement of the chlorine atom with various amines and subsequent esterification with bromoacetophenones, afforded substituted phenacylanthranilates. Their cyclization by heating in sulfuric acid gave corresponding hydroxyquinolinones of excellent purity.

4-Chloro-2-fluoro-5-nitrobenzoic acid is a commercially available multireactive building block that can serve as a starting material in heterocyclic oriented synthesis (HOS) leading to various condensed nitrogenous cycles. This work describes its ability for the preparation of substituted nitrogenous heterocycles having 5-7-membered cycles via polymer-supported o-phenylendiamines. Immobilization of this compound on Rink resin followed by further chlorine substitution, reduction of a nitro group and appropriate cyclization afforded benzimidazoles, benzotriazoles, quinoxalinones, benzodiazepinediones and succinimides. The method developed is suitable for the synthesis of diverse libraries including the mentioned types of heterocycles, which have significant importance in current drug discovery. In this paper, we also report limitation of these method and unsuccessful attempt to prepare an 8-membered benzodiazocine cycle.

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