A method of lowering cholesterol which comprises administering to a host requiring such treatment an effective amount of a compound of the formula ##STR1## wherein one of R.sup.1 and R.sup.2 is C.sub.1-7 -alkyl and the other is C.sub.1-7 -alkyl or C.sub.2-6 -alkenyl-methyl;L is C.sub.1-11 -alkylene or C.sub.2-11 -alkenylene optionally bonded to the phenyl group via an O atom or L is 1,4-phenylene;n is 0 or, when L contains an O atom, n is 0 or 1;Q is C.sub.1-7 -alkyl, C.sub.2-10 alkenyl or a group of formula ##STR2## wherein R is H, halogen, CF.sub.3, CN or NO.sub.2 ; R.sup.3 and R.sup.4 are H, C.sub.1-4 -alkyl or halogen; andR.sup.5 is H or, when R is H, R.sup.5 is H or halogen;or a pharmaceutically acceptable acid addition salt thereof, as well as certain compounds of formula I, are described.