PURPOSE: To obtain indolines useful as intermediates for drugs (especially amino acids) or agricultural chemicals by an easy reaction operation, in high yield, industrially and advantageously, by subjecting 2-(o-aminophenyl)ethanols to ring closure through dehydration in the presence of hydrobromic acid.
CONSTITUTION: A compound shown by formula I (R is H, CH3 or CH2OH; X and Y are H, NH2, halogen, 1W4C alkyl, 1W4C alkoxy or OH) is subjected to ring closure through dehydration in the presence of ≥0.01mol. equivalent, preferably ≥2mol. equivalent based on the compound of hydrobromic acid by the use of preferably water as a reaction solvent at 40W200°C preferably 80W150°C to give the aimed compound shown by formula II (R' is H, CH3 or CH2Br; X' and Y' are H, NH2, halogen, 1W4C alkyl or OH) in high yield and readily. Since indolines obtained by this method have sufficient purity, the indolines are directly usable as they are for indole production.
| WO/1998/035939 | MALONIC DIAMIDE DERIVATIVES AND USE THEREOF |
| WO/1989/002923 | PROCESS FOR PREPARING PURIFIED AQUEOUS INDOLE SOLUTION |
| JP2013525438 | Human pyruvate kinase activator |
TANAKA HIDEO
MURAKAMI YASUO
KAMIMURA TAKAHIKO
AIZAWA TAKAO
| JPS52142063A | 1977-11-26 | |||
| JPS58146562A | 1983-09-01 | |||
| JPS58146563A | 1983-09-01 |