Improvements in or relating to novel chemical compounds useful in the synthesis of lysergic acid and its homologues, and process for preparing such compounds

摘要

The invention comprises hexahydro-benz-[cd] indoles of the formula where R1 is alkyl (C1-C8), and acid addition salts thereof. These are made by reacting N-acyl-4-halo-5-oxo-hexahydro-benz[cd] indoles (see Specification 774,985) with alkylamino-acetone ketals and then hydrolysing the products with a strong non-oxidizing mineral acid. An example is given of the condensation of N-benzoyl-4-bromo-5-oxo-hexahydrobenz[cd] indole with methylamino-acetone ethylene ketal and hydrolysis of the benzoyl and ketal groupings in the product. Other starting materials are mentioned in which the N-acyl group is acetyl or benzoyl (or in general aliphatic, aromatic or araliphatic), R1 is methyl, ethyl, propyl, butyl or heptyl and the ketal group is ethylene, propylene or diethyl (C1-C8 alkyl in general). The products are intermediates for the synthesis of lysergic acid and its homologues. Alkylaminoacetone ketals of the formula where R1 is C1-C8 alkyl and R2 and R3 are lower alkyl or together represent an alkylene chain of 2-3 carbon atoms, are made by condensing the corresponding chloroacetone ketal with the appropriate alkylamine.