GB304439A - Manufacture of 2 : 3-aminonaphthol and derivatives thereof - Google Patents

Abstract

304,439. Imray, O. Y., (I. G. Farbenin dustrie Akt.-Ges.). Dec. 15, 1927. 2: 3-Aminonaphthol and its derivatives are obtained when an O-arylsulphonic ester of 2: 3- hydroxynaphthalenecarboxyamide or a nuclear substitution product thereof is subjected to Hofmann's reaction and the 0-arylsulphonyl-2: 3- aminonaphthol or nuclear substitution product thereof thus produced is hydrolyzed. In examples, (1) p-toluenesulphonyl-2-hydroxynaphthalene-3-carboxyamide (obtained from p-toluenesulphonchloride and 2-hydroxynaphthalene-3-carboxyamide) is converted into 3-amino-2-p-toluenesulphonylnaphthol which is hydrolyzed to 2: 3- aminonaphthol, (2) O-benzenesulphonyl-2-hydroxynaphthalene-3-carboxyamide (obtained from benzenesulphochloride and 2-hydroxynaphthalene- 3-carboxyamide) is converted into 3-amino-2-benzenesulphonylnaphthol which on hydrolysis gives 2: 3-aminonaphthol, (3) 6-bromo-2-hydroxynaphthoylamide (obtained from 6-bromo-2-hydroxy-3- naphthoyl chloride and ammonia) is esterified with p-toluenesulphochloride and the 6-bromo-O- p-toluenesulphonyl-2-hydroxynaphthalene - 3 - carboxyamide thus obtained converted into 6-bromo- O-p-toluenesulphonyl-3-amino-2-naphthol which is hydrolyzed to 6-bromo-3-amino-2-naphthol. 6-Bromo-2-hydroxy-3-naphthoyl chloride is obtained from thionyl chloride and 6-bromo-2- hydroxy-3-naphthoic acid.