[Cardiovascular action of 1,2,4-benzothiadiazine-1,1-dioxide derivatives. VI].

A series of 3,4-dihydro derivatives of 6-chloro-, 7-chloro-, 5,7-dichloro-, 6,7-dichloro-, 5,7-dibromo-, 5-nitro-7-chloro-, 7-nitro-, 7-amino-1,2,4-benzothiadiazine-1,1-dioxide, various substituted on the heterocyclic carbon, was prepared and tested for cardiovascular activity. It was found that in this series of compounds cardiac activity predominates and is exclusively of the depressant type. Bradycardial activity seems to be affected both by the nature of the substituent on the heterocyclic carbon atom and by the substituents on the benzene ring. An alkyl chain of three carbon atoms, normal or alpha-ethylsubstituted, on C3 and the presence of a chlorine atom in positions 6 or 7 seem to be the most significant structural features for this activity. Some of the substances tested showed a pressor effect (hypotension and/or increase in differential pressure).