Tetrahydropyran derivatives

A compound of formula I ##STR24## wherein R.sub.1 represents a group of formula ##STR25## wherein either R.sub.7 represents optionally protected hydroxy, acyloxy, halogen,--OR.sub.10 wherein OR.sub.10 represents lower alkoxy, optionally protected --O(CH.sub.2).sub.m OH wherein m is a number from 2 to 4, or --OCONH.sub.2, and R.sub.7a represents hydrogen,

• or R.sub.7 and R.sub.7a together represent oxo,
• R.sub.8 represents hydroxy or methoxy, and
• R.sub.9 represents hydroxy or acyloxy;
• R.sub.2 represents hydrogen, acyloxy or optionally protected hydroxy and there is a single or a double bond between the two carbon atoms joined by a dotted line;
• R.sub.3 represents methyl, ethyl, n-propyl or allyl;
• either R.sub.4 represents hydrogen or hydroxy and R.sub.4a represents hydrogen,
• or R.sub.4 and R.sub.4a together represent oxo;
• either R.sub.5 represents hydroxy and R.sub.5a represents hydrogen,
• or R.sub.5 and R.sub.5a together represent oxo;
• and
• A represents a group of formula --CH(OR.sub.6)--CH.sub.2 --(CH.sub.2).sub.n -- or --CH.dbd.CH--(CH.sub.2).sub.n --, whereby the (CH.sub.2).sub.n -- part thereof is linked to the carbon atom,
• R.sub.6 represents lower alkyl and
• n represents the number 1 or 2;
• in free form or in pharmaceutically salt form.