| 摘要 |
1451410 2 - (2 - Hydroxyphenyl) - benzotriazole-1-oxides CIBA-GEIGY AG 26 Nov 1974 [27 Nov 1973] 10844/76 Divided out of 1451409 Heading C2C A process for the production of a 2-(2- hydroxyphenyl)-benzotriazole-1-oxide of the formula wherein R 1 is hydrogen or halogen; R 2 is hydrogen, alkyl, alkoxy, alkylsulphonyl, acylamino, -SO 3 H, -COOH or halogen; R 3 is hydrogen, alkyl, cycloalkyl, aralkyl, aryl or halogen; R 4 is hydrogen alkyl, alkoxy or -OH ; R 5 is hydrogen, alkyl, cycloalkyl, aralkyl, aryl, carboxyalkyl, alkoxy, acylamino, or halogen, comprises reducing a 2-nitro-2<SP>1</SP>-hydroxyazobenzene of the formula by means of hydrazine hydrate. The reduction is suitably effected using 0À5 mol hydrazine hydrate in a high-boiling ether in the presence of a base and at a temperature of from 70‹ to 100‹ C. |
