Patent ID: 7619095

Claim:
A process for the preparation of 4-[2-(Di-n-propylamino)ethyl]-2,3-dihydro-1H-indol-2-one of formula (I) and its pharmaceutically acceptable salts or solvates Comprising: (a) reducing 2-Methyl-3-nitro-benzoic acid of formula (VIII) with alkali metal borohydride in presence of sulfonic acid or sulfuric acid, to give 2-Methyl-3-nitrobenzyl alcohol of formula (IX); (b) converting 2-Methyl-3-nitrobenzyl alcohol of formula (IX) to 2-Methyl-3-nitrophenyl acetic acid of formula (XII); (c) reducing 2-Methyl-3-nitrophenyl acetic acid of formula (XII) with alkali metal borohydride in presence of sulfonic acid or sulfuric acid, to give novel 2-Methyl-3-nitro-phenyl ethyl alcohol of formula (A); (d) reacting 2-Methyl-3-nitro-phenyl ethyl alcohol of formula (A) with halogenating agent or compounds of formula R 1 —X, in presence of organic base to give novel compound of formula (B); wherein R represents a halogen atom, lower alkanesulfonyloxy group, substituted or unsubstituted arylsulfonyloxy group, arylalkylsulfonyloxy; R 1 represent lower alkanesulfonyloxy, substituted or unsubstituted arylsulfonyloxy, arylalkylsulfonyloxy and X represent a halogen atom; (e) reacting compound of formula (B) with Di-n-propylamine or its salt, to give 2-Methyl-3-nitrophenylethyl-N,N-di-n-propyl amine of formula (V) (f) optionally treating 2-Methyl-3-nitrophenylethyl-N,N-di-n-propyl amine of formula (V) with acid to prepare 2-Methyl-3-nitrophenylethyl-N,N-di-n-propyl amine acid addition salt; (g) converting 2-Methyl-3-nitrophenylethyl-N,N-di-n-propyl amine (V) or its acid addition salts to 4-[2-(Di-n-propylamino)ethyl]-2,3-dihydro-1H-indol-2-one of formula (I) or its pharmaceutically salts or solvates.