GB1048868A - New pyridobenzothiadiazepine derivatives and process for producing same - Google Patents

Abstract

Novel compounds of the formula <FORM:1048868/C2/1> wherein R1 and R2, in the 7, 8 or 9 position, either independently of each other represent hydrogen, chlorine, bromine, the tri-fluoromethyl group or alkyl or alkoxy radicals containing 1 to 5 carbon atoms or taken together can also represent the methylene dioxy group are prepared by treating compounds of the formula <FORM:1048868/C2/2> wherein R1 and R2 have the above significance with a condensing agent either selected from thionyl chloride, phosphorus pentachloride and phosphorus trichloride when R3 is hydrogen or selected from butyl lithium and sodium hydride when R3 is an aryl, arylmethyl or C1 to C4 alkyl radical. Pharmaceutical compositions having diuretic and hypotensive activity and which may be administered orally contain as the active ingredient at least one compound of the first general-formula above. Substituted pipecolinic acid corresponding to the second general formula above wherein R3 represents hydrogen is prepared by condensing a compound of the formula <FORM:1048868/C2/3> wherein Hal represents chlorine or bromine and R1 and R2 have the above significance with a suitable ester of pipecolinic acid, reducing the nitro group in the resulting 2-nitrobenzenesulphonyl - pipecolinic ester by, for example, catalytic hydrogenation to give the corresponding amino compound which is then saponified to give the desired starting material. 4 - Chloro - 6 - nitrobenzenesulphonyl chloride is prepared by reacting 4,41-dichloro-6,61-dinitrophenyl-disulphide with chlorine gas.