COMPOSTI ETEROSICLICI DOTATI DI ATTIVITA' FARMACOLOGICA E PROCEDIMENTO PER LA LORO PREPARAZIONE

Compounds are disclosed of general formula (I): (I) wherein R1 and R2 each independently represents a hydrogen atom, or an aryl, aralkyl, cycloalkyl, fluoroalkyl or alkyl group, which alkyl group is optionally substituted by an alkenyl group or by a group -OR7 or by where R7 and R8 each independently represents a hydrogen atom, an alkyl, aryl or aralkyl group; or R1 and R2 together with the nitrogen atom to which they are attached form a saturated monocyclic 5 to 7 membered ring which may contain a further hetero function (viz-O-, -NH or R3 and R4 have the same meanings as R1 and R2 and may together form an aralkylidene group; R5 represents a hydrogen atom or an alkyl or aralkyl group; R6 represents a hydrogen atom or an aryl or C1-C3 alkyl group; Alk represents an C1-C4 alkylene group optionally substituted at one or more of its carbon atoms by one to three C1-C3 alkyl groups; and X represents an oxygen or sulphur atom, and its physiologically acceptable salts, hydrates and bioprecursors. The indoles (I) may be prepared by combinations of reactions to introduce the desired substituents into suitable intermediates either before or after cyclization to form the indole nucleus. The compounds have selective actions on blood vessels and, in particular exhibit antihypertensive properties. They may be formulated in conventional manner as pharmaceutical compositions.