Phosphinic acid derivatives, their preparation and their use

A compound of the formula I ##STR9## in which A is a radical of the formula IIa, ##STR10## in which Y is oxygen;

• R.sup.1 is oxygen;
• R.sup.2 is
• hydrogen,
• (C.sub.1 -C.sub.6)-alkyl,
• (C.sub.7 -C.sub.13)-arylalkyl,
• (C.sub.6 -C.sub.12)-aryl,
• all of which are unsubstituted or substituted by hydroxyl,
• (C.sub.1 -C.sub.10)-alkyl, (C.sub.1 -C.sub.3)-alkoxy, F, Cl or Br;
• an equivalent of a physiologically tolerated salt, or
• a residue of a phosphinic acid prodrug;
• B is a radical of the formula IIIa ##STR11## where L is oxygen;
• D and D* are, independently of each other,
• R.sup.6 {(C.sub.1 -C.sub.6)-alkyl},
• where the alkyl is saturated or unsaturated, branched or unbranched,
• where R.sup.6 is
• (C.sub.6 -C.sub.12)-aryl, unsubstituted or substituted by R.sup.7 ;
• or
• (C.sub.3 -C.sub.12)-cycloalkyl, unsubstituted or substituted by R.sup.7 ;
• where R.sup.7 is, independently of each other,
• --R.sup.8
• where R.sup.8 is
• hydrogen, or
• (C.sub.1 -C.sub.6)-alkyl, unsubstituted or substituted by hydroxyl;
• E and E* are benzyl.