Condensed heterotricycles: Pyrrolo[l,2-α]quinoxaline derivatives

Nagarajan, K. ; Ranga Rao, V. ; Venkateswarlu, A. (1972) Condensed heterotricycles: Pyrrolo[l,2-α]quinoxaline derivatives Indian Journal of Chemistry, 10 . pp. 344-350. ISSN 0019-5103

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Treatment of l-(o-aminophenyl)pyrrole (II) with phosgene gives lactam (IV), from which 4-chloro- (V) and 1,4-dichloro- (VI) derivatives become available. Acid hydrolysis of VI affords chlorolactam (IX). Treatment of IV and IX with appropriate halides leads to N-aminoalkyl derivatives (X) and (XI) respectively. V and VI react with amines to yield aminoquinoxalines VII and VIII respectively while V and aminoalkoxide give XII. The action of CNBr on II results in the formation of ziminoquinoxaline VII (R = NH), while POCI cyclization of the phenyl urea of II affords the anilino compound VII (R= NHPh). The mercapto derivative XIII is obtained from II using CS, and is utilized to form S-aminoalkyl derivatives. Oxidative treatment of II with benzaldehyde produces the phenylquinoxaline (XVII), while the chloroacetyl derivative cyclizes under milid conditions to the chloromethyl compound XIX. The acetylene dicarboxylic ester adducts XXI and XXII of II, upon treatment with PPA, undergo cyclization to XXIII and XXIV, with elimination of alkyl acetate. A mechanism is suggested for this novel cyclization. Bromination and nitration products of the parent pyrrolo[l,2-o]quinoxaline (III) are described.

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Deposited On:19 Jun 2012 07:23
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