Phosphonyl hydroxyacyl amino acid derivatives as antihypertensive

A compound of the formula ##STR293## and pharmceutically acceptable salts thereof wherein:

• ##STR294## R.sub.1 is alkyl of 1 to 10 carbons, amino substituted lower alkyl, halo substituted lower alkyl, ##STR295## --(CH.sub.2).sub.q -cycloalkyl containing 3 to 7 carbons in the cycloalkyl portion, ##STR296## wherein q is zero or an interger from 1 to 7:
• R.sub.11 is hydrogen, lower alkyl of 1 to 4 carbons, lower alkoxy of 1 to 4 carbons, lower alklthio of 1 to 4 carbons, chloro, bromo, fluoro, trifluoromethyl, hydroxy, phenyl, phenoxy, phenylthio, or phenylmethyl;
• p is one, two or three provided that p is more than one only if R.sub.11 is hydrogen, methyl, methoxy, chloro, or fluoro;
• R.sub.19 and R.sub.20 are independently selected from the group consisting of hydrogen, lower alkyl, halo substituted lower alkyl, ##STR297## --(CH.sub.2).sub.m -cycloalkyl containing 3 to 7 carbons in the cycloalkyl portion ##STR298## m is zero, one, two or three, wherein R.sub.11 and p are as defined above;
• R.sub.2 is hydrogen, lower alkyl, halo substituted lower alkyl, ##STR299## --(CH.sub.2).sub.r --NH.sub.2, --(CH.sub.2).sub.r --S--lower alkyl, ##STR300## wherein r is an integer from 1 to 4;
• R.sub.3 and R.sub.6 are independently selected from hydrogen, lower alkyl, benzyl, benzhydryl, alkali metal or ##STR301## wherein R.sub.15 is hydrogen, lower alkyl, cycloalkyl containing 3 to 7 carbons, or phenyl, and R.sub.16 is hydrogen, lower alkyl, lower alkoxy, phenyl, or R.sub.15 and R.sub.16 taken together are --(CH.sub.2).sub.2 --, --(CH.sub.2).sub.3, --CH.dbd.CH--or ##STR302##