Prostanoic acid derivatives and their preparation

A compound of the formula ##STR74## wherein R.sub.1 is ##STR75## wherein R.sub.6 is hydroxy, a straightchain or branched alkoxy of 1-10 carbon atoms;

• aryloxy;
• O--CH.sub.2 --U--V wherein U is a direct bond, carbonyl or carbonyloxy and V is a phenyl ring substituted by one or more of phenyl, alkoxy of 1-2 carbon atoms, or halogen A is cis- or trans--CH.dbd.CH--;
• B is trans--CH.dbd.CH-- or --C.tbd.C--;
• W is free or functionally modified hydroxymethylene, a free or functionally modified carbonyl, or ##STR76## wherein R.sub.11 is alkyl of 1-5 carbon atoms and the OH-group can be in the .alpha.- or .beta.-position and can be functionally modified;
• Z is carbonyl or hydroxymethylene, either of which can be free or functionally modified;
• X Y is either ##STR77## when Z is a free or functionally modified hydroxymethylene group, or is either ##STR78## or --CH.dbd.CH--, when Z is a free or functionally modified carbonyl group, wherein R.sub.12 is a hydrogen atom, methyl, or a free or functionally modified hydroxy;
• R.sub.2 is a hydrogen atom or alkyl;
• R.sub.3 is a hydrogen atom or alkyl;
• one of R.sub.4 and R.sub.5 is a chlorine atom and the other is methyl;
• and, when R.sub.6 is hydroxy, the physiologically acceptable salts thereof with bases;
• wherein "functionally modified" OH refers to OH etherified by tetrahydropyranyl, tetrahydrofuranyl, .alpha.-ethoxyethyl, trimethylsilyl, dimethyl-tert-butylsilyl or tri-p-benzylsilyl or esterified by the acyl group of a C.sub.1-15 organic carboxylic or sulfonic acid;
• and "functionally modified" carbonyl refers to carbonyl converted to a cyclic ketal with ethylene glycol, 1,3-propanediol, 2,2-demethyl-1,3-propanediol, 1,2-cyclopentanediol, or glycerol.