TETRACYKLISKA INDOLDERIVAT

Compounds which in form of therapeutic compositions exhibit antihypertensive activity and are of low toxicity. These compounds are of general formula I wherein R1 represents a hydrogen atom, or a carboxy, alkoxycarbonyl, the alkoxy group having 1 to 4 carbon atoms, piperidinocarbonyl, 1-pyrrolidinylcarbonyl, morpholinocarbonyl, carbamoyl or benzylcarbamoyl group, or an alkylcarbamoyl or dialkylcarbamoyl group in which the or each alkyl group has from 1 to 4 carbon atoms, R2 represents a hydrogen or fluorine atom, or a cyano, acetyl or carbamoyl group, R3 represents a hydrogen atom or a methyl group and@@@ represents a single or double bond, with the proviso, that R1 and R2 do not simultaneously represent hydrogen atoms, or pharmaceutically acceptable salts thereof, their preparation and therapeutic compositions containing them.