alpha-Hydrazino-indolyl-(3)-carbonsaeurederivate und Verfahren zu ihrer Herstellung

The invention comprises compounds of the general formula and non-toxic acid-addition salts thereof in which each of R1, R2 and R3 is a hydrogen atom or a C1-5 alkyl group each of R4 and R6 is a hydrogen atom or a C1-6 alkanoyl group and R5 is a hydrogen atom, or a C1-5 alkyl, aralkyl or a C1-6 alkanoyl radical together with a process for the preparation of compounds of the formula by agitating a mixture of a ketone or aldehyde of the formula in which R7 is a hydrogen atom or a C1-5 alkyl or aralkyl group or a bisulphite addition of such a ketone, with hydrazine and a water soluble cyanide salt, treating the resulting a -hydrazinonitrile successively with hydrochloric acid in the cold and with hydrobromic acid at a flux temperature and, optionally, esterifying the resulting a -hydrazino acid by heating with an alkanol R11OH, where R11 is a C1-5 alkyl radical in the presence of a mineral acid, and, optionally, acylating the acid or its ester by heating with a C1-6 alkanoic anhydride and an organic base. 5-Benzyloxy-3-indolyl-alkan-als and -ones used as starting materials are prepared by reacting 5-benzyloxyindole with an appropriate nitroalkylene to form a 5-benzyloxy-3-indolyl-nitro-alkane which is treated with an alkali and then a strong acid (Nef degradation). The N-substituted-indole analogues are similarly prepared. Pharmaceutical compositions comprise the compounds of the invention together with a carrier and may be in the form of tablets, capsules, powders, or other dosage forms useful for oral ingestion, or a sterile solution for parenteral use. The compounds are antihypertensive agents.