Verfahren zur Herstellung von Dibenzothiazinderivaten

The invention comprises compounds of formula wherein A is an alkylene group, R1 and R2 are hydrogen atoms or alkyl, alkenyl or hydroxyalkyl groups and the benzene rings may be substituted by one or more halogen atoms or alkyl or trifluoromethyl groups, acid addition and quaternary ammonium salts thereof, and their preparation by (a) reaction of an N-unsubstituted dibenzothiazine or a salt thereof with a compound of formula X-A-NR1R2 or a salt thereof, wherein X is a halogen atom, (b) reaction of an N-(A-X) substituted dibenzothiazine with an amine HNR1R2, (c) removal of the protecting group from a compound of formula wherein B is a hydrocarbon group, (d) diazotization and heating of a compound of formula or (e) hydrogenolysis of a compound wherein one of the groups R1 and R2 is a benzyl group, (f) reaction of a free amino product with an aldehyde or ketone R1COR2 under reducing conditions, or (g) reduction of a compound of formula wherein D is an alkylene group having one fewer carbon atom than the group A. Compounds of formula wherein the benzene rings may be substituted as defined above are prepared by processes analogous to (d) above. Compounds of formula are prepared by processes analogous to (a) and (b) above. N-Haloalkyl and N-cyanoalkyl-dibenzothiazine starting materials are prepared by reaction of an N-unsubstituted dibenzothiazine or a salt thereof with a dihaloalkane or a halonitrile. Compounds of formula wherein R1 or R2 is a benzyl group are prepared by processes analogous to (a) and (b) above. 41-Methyl, chloro- or bromo- and 2-trifluoromethyl derivatives of (21-amino-benzenesulphonyl)-aniline are prepared by reduction of the corresponding 21-nitro-compounds. 41-Chloro- and bromo- and 2-trifluoromethyl derivatives of (21-nitro-benzenesulphonyl)-aniline are prepared by reaction of an optionally substituted 2-nitro-benzenesulphonyl chloride with an optionally substituted aniline. The compounds of the invention have antidepressant and monoamine oxidase inhibiting activity and may be used in pharmaceutical compositions in combination with a carrier, for example in forms suitable for oral or parenteral administration.