GB1215815A - Production of quinoxaline-di-n-oxides and benzimidazole mono- and di-n-oxides - Google Patents

Abstract

1,215,815. Quinoxaline and benzimidazole N- oxides. RESEARCH CORP. 20 Dec., 1967, No. 57874/67. Heading C2C. A process for producing quinoxaline di-N- oxides, benzimidazole-di-N-oxides and 1-hydroxybenzimidazole-3-oxides comprises reacting an isobenzofuroxan with a compound containing a methylene group which is activated by two electron withdrawing groups or a compound containing a methylene group which is activated by one electron withdrawing group, said one electron withdrawing group being a nitro group or a carbonyl group of a ketone or an aldehyde, in the presence of a base with the proviso in some cases that when a keto group is present in the molecule said base is not ammonia nor a primary aliphatic or cycloaliphatic amine. Examples of such compounds containing activated methylene groups include ketones, aldehydes, #-diketones, #-keto ester, malonic esters and nitroalkanes. The B ring of the heterocycle may be substituted by alkyl, cycloalkyl, aryl, aralkyl, alkoxy, carboxy, esterified carboxy, acyl, carboxyamide, cyano, amino, amide, oximino methyl, formyl and formyl-dimethyl acetal groups. The A ring may be substituted by alkyl, acyl, trifluoromethyl groups or halogen atoms. The following quinoxaline di-N-oxides, stated to be novel, are thus prepared; 2-cyano-3- amino; 2-formyldimethyl acetal; 2-carboethoxy - 3 - formyldiethylacetal; 2 - carbomethoxy - 3 - hydroxy; 2 - carboethoxy - 3- hydroxy -; 2 - carboethoxymethyl - 3 - methyl; 2 - carbomethoxymethyl - 3 - carbomethoxy -; 2 - (2<SP>1</SP> - diethylaminoethylene. The following, also stated to be novel, are prepared: 1-hydroxy - 2 - carboethoxybenzimidazole - 3 - oxide, 1 - hydroxy - 2 - benzimidazole - propionamide- 3 - oxide, 2,2 - dimethyl - 2H - benzimidazole- 1,3 - dioxide, 2,2 - pentamethylene - 2H - benzimidazole-1,3-dioxide.