7,8-Dihydro-2,5 ,8-trisubstituted-7-oxo-pyrido[2,3-d]-pyrimidine-6-carboxylic acid amides

A compound of the formula:

• ##STR11## in which R.sup.2 is hydrogen, hydroxy, alkyl of 1 to 6 carbon atoms, alkylthio of 1 to 6 carbon atoms, phenyl, 4-methoxyphenyl, 4-chlorophenyl, 1-pyrrolidinyl or methylphenylamino;
• R.sup.5 is hydroxy, alkylamino of 1 to 6 carbon atoms, 2-hydroxyethylamino, 2-alkoxyethylamino of 3 to 8 carbon atoms, dialkylamino wherein each alkyl group contains from 1 to 6 carbon atoms, 4-methyl-1-piperazinyl, 4-morpholinyl or 1-pyrrolidinyl when R.sup.2 is other than alkylthio and R.sup.8 is other than alkyl, or amino when R.sup.8 is other than alkyl;
• R.sup.6 is amino, alkylamino of 1 to 6 carbon atoms or dialkylamino where each alkyl group contains from 1 to 6 carbon atoms and
• R.sup.8 is hydrogen, alkyl of 1 to 6 carbon atoms, 2-alkoxyethyl of 3 to 6 carbon atoms, allyl, propargyl, phenyl, 4-methoxyphenyl, 4-chlorophenyl, benzyl, 4-methoxybenzyl, 4-chlorobenzyl, 4-(4-morpholinyl)phenyl or piperonyl.