| 摘要 |
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, 1-4C alkyl, 1-4C 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 40-200 deg.C preferably 80-150 deg.C to give the aimed compound shown by formula II (R' is H, CH3 or CH2Br; X' and Y' are H, NH2, halogen, 1-4C 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.
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