GB1176804A - Novel 1-(2-Aminophenyl)-1,2,3,4-tetrahydroisoquinolines - Google Patents

Abstract

1,176,804. 1,2,3,4 - Tetrahydroisoquinolines. DR. KARL THOMAE G.m.b.H. 29 June, 1967 [29 June, 1966; 24 May, 1967], No. 30152/67. Heading C2C. Novel compounds of formula (wherein R is H, C 1-3 alkyl, aralkyl, or an aliphatic, aromatic or araliphatic acyl group, R 1 is C 1-5 alkyl, R 2 is C 1-5 alkyl or benzyl, or R 1 and R 2 with the intervening carbon atom form a cycloaliphatic ring, and R 3 is H or methyl) and their physiologically compatible acid addition salts with inorganic or organic acids, are prepared (A) by reducing the corresponding 1- (2 - aminophenyl) - 3,4 - dihydroisoquinolines, any acyl group (R) being retained, reduced or cleaved during this reaction depending upon the reducing agent; or (B) by reducing the corresponding 1 - (2 - nitrophenyl) - 3,4 - dihydroisoquinolines either in a single step or in two steps via a 1-(2-nitrophenyl)-1,2,3,4- tetrahydroisoquinoline; or (C) by condensing an appropriate 2-phenyl-ethylamine with an appropriate o-aminobenzaldehyde either in a single step or in two steps via a Schiffs base; or (D) by condensing an appropriate 2-phenylethylamine with o-nitrobenzaldehyde, reducing the nitro group to amino in the resulting Schiffs base which is then cyclized. Processes A-D yield bases of Formula I which may be salified when required. Product interconversions described are (a) alkylation, aralkylation and acylation of compounds wherein R is H to obtain compounds wherein R is other than H, and (b) reduction of compounds wherein R is acyl to obtain compounds wherein R is alkyl or aralkyl. 1 - 2 - (Aminophenyl) - 3,4 dihydroisoquinolines, with substituents R, R 1 , R 2 and R 3 as in Formula I are prepared by cyclizing oaminobenzonitrile with an appropriate carbinol, followed when required by conversion of R as described at (a) and (b) above. 1 - (2 - Nitrophenyl) - 3,4 - dihydroisoquinolines with substitutents R 1 -R 3 as in Formula I are prepared by cyclizing o-nitrobenzonitrile with an appropriate carbinol. Compounds of Formula I and their compatible addition salts with inorganic and organic acids are stated to possess antiphlogistic and anti-pyretic activity, and may be made up with carriers or excipients into pharmaceutical compositions which may be administed by oral, parenteral or rectal routes.