Derivatives of 5-Oxy-pyrido[2,3-b]quinoxaline-9-carboxylic acid: A tricyclic system useful for the synthesis of potential intercalators

✍ Scribed by Athanasia Varvaresou; Kriton Iakovou

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2002
• Tongue: English
• Weight: 40 KB
• Volume: 39
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570390610

✦ Synopsis

Abstract

The synthesis of a new series of 5‐oxy‐pyrido[2,3‐b]quinoxaline‐9‐carboxamides 4a‐i and N^1^,N^2^‐Bis(5‐oxy‐pyrido[2,3‐b]quinoxaline‐9‐benzoyl)ethylenediamine (5) is reported starting from 2‐chloro‐3‐nitropyri‐dine. Fundamental steps of the synthetic pathway are i) preparation of 2‐(3‐nitro‐pyridin‐2‐ylamino)benzoic acid (1) via copper‐catalyzed condensation of 2‐chloro‐3‐nitropyridine with o‐anthranilic acid, ii) intramolecular cyclization of the acid 1 to 5‐oxy‐pyrido[2,3‐b]quinoxaline‐9‐carboxylic acid (2b) upon treatment with concentrated sulfuric acid and oleum and iii) conversion of the acid 2 to the desired amides 4a‐i and 5. Compounds 4a‐i and 5 are oxygenated azaanalogs of phenazines, a wellknown series of intercalators with cytotoxic activity.