Phosphorus containing compounds as antihypercholesterolemic and antiatherosclerotic agents

A compound of Formula I ##STR31## wherein R, R.sup.1 and R.sup.2 are each independently hydrogen, alkyl of from one to six carbon atoms, alkoxy of from one to six carbon atoms, halogen, or trifluoromethyl;

• X and Y are each independently alkyl of from one to twenty carbon atoms, with the proviso that X and Y are not both alkyl, aryl, --OR.sup.5 wherein R.sup.5 is
• alkyl of from one to twenty carbon atoms,
• --(CH.sub.2).sub.m -aryl wherein m is zero or an integer of 1, 2, or 3 or ##STR32## wherein m is as defined above ##STR33## wherein R.sup.6 and R.sup.7 are each independently hydrogen, alkyl of from one to twenty carbon atoms, --(CH.sub.2).sub.o -aryl wherein O is an integer of 1, 2, or 3 or ##STR34## wherein O is as defined above or X and Y are taken together with the phosphorus atom to which they are attached to form a ring denoted by ##STR35## wherein R.sup.8 is hydrogen,
• alkyl of from one to twenty carbon atoms, or
• --CH.sub.2 -aryl and
• R.sup.9 and R.sup.10 are each independently hydrogen, alkyl of from one to twenty carbon atoms, or aryl;
• provided
• both X and Y are not --OR.sup.5 wherein R.sup.5 is alkyl of from one to six carbon atoms or phenyl;
• or a pharmaceutically acceptable base addition salt thereof.