Azetidine derivatives of formula ##STR1## and their pharmaceutically acceptable acid addition salts are disclosed. In the formula R is hydrogen or one or more specified substituents. The compounds have hypotensive activity. Some are also 5-HT.sub.1A agonists.

Compounds of the formula I ##STR1## wherein R.sub.2 --C, R.sub.3 --C, R.sub.4 --C or R.sub.5 --C may be replaced by N; and wherein n is 1, 2 or 3; R.sub.1 is aryl, cycloalkyl or heterocyclyl; R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are independently hydrogen, optionally substituted alkyl, halo, amino, substituted amino, trifluoromethyl, cyano, carboxyl, alkoxycarbonyl, aralkoxycarbonyl, (alkyl, aryl or aralkyl)-thio, (alkyl, aryl or aralkyl)-oxy, acyloxy, (alkyl, aryl or aralkyl)-aminocarbonyloxy; or any two of R.sub.2, R.sub.3, R.sub.4 and R.sub.5 at adjacent positions are alkylenedioxy; R.sub.6 is hydrogen, optionally substituted alkyl, amino, substituted amino, acylamino, ##STR2## wherein R.sub.a is hydrogen or optionally substituted alkyl, R.sub.b and R.sub.c are independently hydrogen, optionally substituted alkyl, cycloalkyl, aryl or heterocyclyl; or R.sub.b and R.sub.c together represent lower alkylene or lower alkylene interrupted by O, S, or N--(H, alkyl or aralkyl); R.sub.d is optionally substituted alkyl, cycloalkyl, aryl or heterocyclyl; and R.sub.e is optionally substituted alkyl, aryl, heterocyclyl, cycloalkyl, amino or substituted amino; and pharmaceutically acceptable salts thereof; and enantiomers thereof; which are useful as inhibitors of microsomal triglyceride transfer protein (MTP) and of apolipoprotein B (ApoB) secretion.

##STR1## Compounds of formula (I) wherein R.sub.2 --C, R.sub.3 --C, R.sub.4 --C or R.sub.5 --C may be replaced by N; and wherein n is 1, 2 or 3; R.sub.1 is aryl, heteroaryl or (aryl or heteroaryl)-lower alkoxy; R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are independently hydrogen, lower alkyl, lower alkoxy, halo, trifluoromethyl or cyano; R.sub.6 is (i) or (ii) m is 1, 2 or 3; R.sub.7 is hydrogen, lower alkyl (aryl or heteroaryl)-lower alkyl, lower alkoxy, (aryl or heteroaryl)-lower alkoxy, hydroxy, oxo, lower alkylenedioxy or lower alkanoyloxy; W is O, S or NR.sub.8 ; R.sub.8 is --COR.sub.a, (iii), --COOR.sub.d, --SO.sub.2 R.sub.e, hydrogen, optionally substituted lower alkyl, aryl, heteroaryl or (aryl or heteroaryl)-lower alkyl; R.sub.a, R.sub.d and R.sub.e are independently optionally substituted lower alkyl, cycloalkyl, adamantyl, aryl, heteroaryl or (aryl or heteroaryl)-lower alkyl; R.sub.b and R.sub.c are independently hydrogen, cycloalkyl, optionally substituted lower alkyl, aryl, heteroaryl or (aryl or heteroaryl) lower alkyl; or R.sub.b and R.sub.c together represent lower alkylene; and pharmaceutically acceptable salts thereof; and enantiomers thereof; which are useful as inhibitors of microsomal triglyceride transfer protein (MTP) and of apolipoprotein B (apoB) secretion.

New tetralin derivatives of the formula I ##STR1## wherein R.sup.1 to R.sup.8 and Z have the meanings indicated herein and salts thereof, exhibit an effect on the cardiovascular system.