Phosphonate, phosphinate derivatives useful as antihypertensive agents

A compound of the formula ##STR21## or pharmaceutically acceptable salts thereof;

• wherein X is --CH.sub.2 -- or a single bond;
• X.sub.1 is --O-- or a single bond;
• X.sub.2 is --Ch.sub.2 --, --O-- or a single bond;
• R.sub.1 is alkyl of 2 to 10 carbon atoms, alkenyl or alkynyl of 3 to 10 carbon atoms or the same groups substituted with F;
• R.sub.2 is H, COOR.sub.6, alkyl of 1 to 10 carbon atoms, alkenyl of 3 to 10 carbon atoms, or the same groups substituted with F;
• R.sub.3 and R.sub.4 are each independently hydrogen, alkyl, aryl or arylalkyl;
• R.sub.6 is alkyl or perfluoroalkyl of 1 to 8 carbon atoms, cycloalkyl of 3 to 6 carbon atoms, phenyl or benzyl;
• R.sub.14 is ##STR22## R.sub.15 is H, halogen, --NO.sub.2, --CN, alkyl of 1 to 4 carbons, acyloxy of 1 to 4 carbons, alkoxy of 1 to 4 carbons, --CO.sub.2 H, CO.sub.2 R.sub.17, --NHSO.sub.2 CH.sub.3, --NHSO.sub.2 CF.sub.3, --CONHOR.sub.18, --SO.sub.2 NH.sub.2, aryl, furyl or ##STR23## R.sub.16 is H, halogen, alkyl of 1 to 4 carbons or alkoxy of 1 to 4 carbons;
• R.sub.17 is hydrogen or ##STR24## R.sub.18 is hydrogen, methyl or benzyl;
• R.sub.19 is alkyl of 1 to 6 carbons, NR.sub.2 R.sub.21 ;
• R.sub.20 and R.sub.21 are independently hydrogen, benzyl, alkyl of 1 to 6 carbons or taken together are 3 to 6 methylene groups forming a 4- to 7-membered ring with the nitrogen atom to which they are attached;
• R.sub.23 is --CO.sub.2 H, --CO.sub.2 R.sub.17,
• X.sub.3 is a carbon-carbon single bond, --CO--, --CH.sub.2 --, and