2-substituted thio or oxy-4-aryl or heterocyclo-5-carboxy-1,4-dihydropyrimidines, composition containing them, and method of using them to reduce blood pressure

A compound of the formula ##STR99## its 3,4-dihydropyrimidine tautomer form, or a pharmaceutically acceptable salt thereof wherein:

• X is oxygen or sulfur;
• R.sub.1 is lower alkyl, lower alkenyl, lower alkynyl, --(CH.sub.2).sub.m -cycloalkyl, --(CH.sub.2).sub.m -aryl, --(CH.sub.2).sub.p --OH, --(CH.sub.2).sub.p --O--lower alkyl, --(CH.sub.2).sub.p --O--(CH.sub.2).sub.m -aryl, --(CH.sub.2).sub.p --SH, --(CH.sub.2).sub.p --S--lower alkyl, --(CH.sub.2).sub.p --S--(CH.sub.2).sub.m -aryl, ##STR100## or halo substituted lower alkyl;
• R.sub.2 is hydrogen, lower alkyl, lower alkenyl, lower alkynyl, --(CH.sub.2).sub.m --cycloalkyl, --(CH.sub.2).sub.m --aryl, --(CH.sub.2).sub.n --OH, --(CH.sub.2).sub.n --O--lower alkyl, --(CH.sub.2).sub.n --O--(CH.sub.2).sub.m --aryl, --(CH.sub.2).sub.n --SH, --(CH.sub.2).sub.n --S--lower alkyl, --(CH.sub.2).sub.n --S--(CH.sub.2).sub.m --aryl, ##STR101## or halo substituted lower alkyl;
• R.sub.3 is hydrogen, lower alkyl, --(CH.sub.2).sub.m --aryl, --(CH.sub.2).sub.m --cycloalkyl, --(CH.sub.2).sub.p --OH, --(CH.sub.2).sub.p --O--lower alkyl, --(CH.sub.2).sub.p --O--(CH.sub.2).sub.m --aryl, --(CH.sub.2).sub.p --SH, --(CH.sub.2).sub.p --S--lower alkyl, --(CH.sub.2).sub.p --S--(CH.sub.2).sub.m --aryl, ##STR102## halo substituted lower alkyl, or a pharmaceutically acceptable salt forming ion;
• R.sub.4 is aryl;
• R.sub.5 and R.sub.6 are independently selected from the group consisting of hydrogen, lower alkyl, and --(CH.sub.2).sub.m --aryl or R.sub.5 and R.sub.6 taken together with the N atom to which they are attached complete a heterocyclic ring of the formula ##STR103## R.sub.8 is hydrogen, lower alkyl of 1 to 4 carbons, lower alkoxy of 1 to 4 carbons, lower alkylthio of 1 to 4 carbons, halo, CF.sub.3, or hydroxy;
• R.sub.9 is hydrogen, lower alkyl of 1 to 4 carbons, ##STR104## R.sub.7 is hydrogen, lower alkyl, --(CH.sub.2).sub.m --aryl, or a pharmaceutically acceptable salt forming ion;
• m is zero or an integer from 1 to 6;
• n is an integer from 1 to 6;
• p is an integer from 2 to 6;
• the term "lower alkyl" refers to straight or branched chain saturated hydrocarbon radicals of one to eight carbons;
• the term "lower alkenyl" refers to straight or branched chain hydrocarbon radicals of two to eight carbons saturated except for one double bond;
• the term "lower alkynyl" refers to straight or branched chain hydrocarbon radicals of two to eight carbons saturated except for one triple bond;
• the term "cycloalkyl" refers to saturated carbocyclic rings of 4 to 7 carbons;
• the term "halo" refers to chloro, bromo, and fluoro;
• and
• the term "aryl" refers to phenyl, 1-naphthyl, 2-naphthyl, mono substituted phenyl, 1-naphthyl or 2-naphthyl wherein said substituent is lower alkyl of 1 to 4 carbons, lower alkoxy of 1 to 4 carbons, lower alkylthio of 1 to 4 carbons, halo, nitro, cyano, hydroxy, amino, --NH--alkyl wherein alkyl is of 1 to 4 carbons, --N(alkyl).sub.2 wherein alkyl is of 1 to 4 carbons, CF.sub.3, NCS, OCHF.sub.2, ##STR105## --O--CH.sub.2 --cycloalkyl, or --S--CH.sub.2 cycloalkyl, and di-substituted phenyl, 1-naphthyl, or 2-naphthyl wherein said substituents are selected from the group consisting of methyl, methoxy, methylthio, halo, CF.sub.3, nitro, amino, and OCHF.sub.2.