QUINOXALINE-DI-N-OXIDE DERIVATES

摘要

1447376 Quinoxaline-di-N-oxide derivatives CIBA-GEIGY AG 4 Sept 1973 [5 Sept 1972] 41620/73 Heading C2C [Also in Division A5] Novel compounds of the Formula I where in R 1 and R 2 are independently hydrogen, C 1-6 alkyl optionally substituted by C 1-6 alkoxycarbonyl ; phenyl optionally substituted by halogen, C 1-6 alkyl, or C 1-6 alkoxy, C 1-6 alkanoyl; benzoyl optionally substituted by halogen, C 1-6 alkyl or C 1-6 alkoxy; C 1-6 alkoxycarbonyl; N,N-di(C 1-6 alkyl)carbamoyl; cyano or amino provided that R 1 and R 2 are not both amino or R 1 and R 2 are together are a C 3-5 polymethylene group; Y is hydrogen or halogen; X is oxygen, sulphur, sulphinyl or sulphonyl; n is 0, 1 or 2 and Z is hydrogen, C 1-6 alkyl, halo-C 1-6 alkyl, halogen or C 1-6 alkoxy may be prepared by (1) for compounds I in which if R 1 or R 2 is amino the other is not amino or cyano reacting in the presence of a base, a compound II with a carbonyl compound R 1 COR 2 R 2 or an enol derivative R 1 C(OA):CHR 2 where A is acyloxy, or N,N-disubstituted amino; (2) for compounds I in which if R 1 or R 2 is amino the the other is not amino or cyano, and in which R 1 and R 2 are hydrogen, C 1-6 alkyl or phenyl or R 1 and R 2 together are a C 3-5 polymethylene group and X is oxygen or sulphonyl, oxidizing the corresponding quinoxaline in which X has the full scope, to its di-N-oxide; (3) for compounds I in which one of R 1 and R 2 is amino and the other is cyano by reacting a compound II with malonic acid dinitrile in presence of a base. 5 - (4 - Methylphenylthio)- benzofurazan N-oxide is prepared by reacting 2-amino-4- (41 - methylphenylthio) - nitrobenzene with sodium hypochlorite and base. 5 - Phenoxytbenzofurazan N - oxide is similarly prepared. 2 - Nitro - 5 - benzylthioaniline is prepared by reacting 2-nitro-5-chloroaniline with benzyl mercaptan in the presence of base. 6 - (p - Methoxy - phenoxy) - 7 - chlorocuinoxaline is prepared by reducing 2-nitro-4- chloro - 5 - (p - methoxy - phenoxy)aniline to 1,2 - diamino - 5 - (p - methoxyphenoxy) - 4- thlorobenzene which is reacted with glyoxal disodium hydrogen sulphate to yield the required compound.