7-substituted derivatives of 3,5-dihydroxyhept-6-ynoic acids and corresponding lactones and their use as hypercholeserolemics

A compound of the formula I ##STR42## or a corresponding lactone of the formula II ##STR43## where, in formulae I and II, R is a radical of formula a ##STR44## in which R.sup.1 and R.sup.2 are, independently of one another, a straight-chain or branched alkyl or alkenyl radical having up to 6 carbon atoms, a saturated or up to doubly unsaturated cyclic hydrocarbon radical having 3-6 carbon atoms or a phenyl radical which is optionally substituted by 1-3 identical or different radicals selected from the group consisting of straight-chain or branched alkyl having up to 4 carbon atoms, halogen, alkoxy having up to 4 carbon atoms and hydroxyl, and

• X.dbd.Y--Z is a group of the formula N.dbd.CR.sup.4 --CR.sup.5, in which
• R.sup.4 and R.sup.5 are, independently of one another, hydrogen, a straight-chain or branched alkyl or alkenyl radical having up to 6 carbon atoms, a saturated or up to doubly unsaturated cyclic hydrocarbon radical having 3-6 carbon atoms or a phenyl radical which is optionally substituted by 1-3 identical or different radicals selected from the group consisting of straight-chain or branched alkyl having up to 4 carbon atoms, halogen, alkoxy having up to 4 carbon atoms and hydroxyl, and
• R.sup.0 is hydrogen, a straight-chain or branched alkyl radical having up to 6 carbon atoms, alkali metal or ammonium, or a physiologically tolerated salt thereof.