2-amino-6-alkyl-5-(4-substituted-1-piperazinyl) pyrimidin-4-ones, the preparation and use thereof

A compound having the structural formula I where

• R.sub.1 is hydrogen or alkyl of from one to six carbon atoms;
• R.sub.2 and R.sub.3 are independently hydrogen or alkyl of from one to six carbon atoms, vinyl or acetylenyl;
• R.sub.4 and R.sub.5 are independently
• (1). hydrogen, halogen, nitro, cyano, trifluoromethyl, hydroxyl, alkyl of from one to six carbon atoms, alkoxyl of from one to six carbon atoms, or alkanoyl of from one to six carbon atoms;
• (2). --NR.sub.6 R.sub.7, where R.sub.6 and R.sub.7 are independently hydrogen, alkyl of from one to six carbon atoms, or alkanoyl of from one to six carbon atoms;
• (3). --COOR.sub.8, where R.sub.8 is hydrogen, a pharmaceutically acceptable metal cation, a pharmaceutically acceptable amine cation, or alkyl of from one to six carbon atoms;
• (5). ##STR7## where R.sub.11 is hydrogen, or alkyl of from one to six carbon atoms;
• (6). --SO.sub.2 R.sub.12, where R.sub.12 is hydroxyl, alkyl of from one to six carbon atoms, alkoxy of from one to six carbon atoms or --NR.sub.13 R.sub.14 where R.sub.13 and R.sub.14 are independently hydrogen or alkyl of from one to six carbon atoms or benzyl;
• and the pharmaceutically acceptable salts thereof.