2,4-Diamino substituted pyridol(3,2-d)pyrimidine as antithrombotic agents

An antithrombotic pharmaceutical dosage unit composition consisting essentially of an inert pharmaceutical carrier and an effective antithrombotic amount of a compound of the formula ##SPC32##

• wherein
• R.sub.1 and R.sub.2 are each morpholino, thiomorpholino, 1-oxido-thiomorpholino, 1,1-dioxido-thiomorpholino or piperidino, where each of these may optionally have a methyl substituent attached thereto;
• piperazino;
• N'-formyl-piperazino;
• N'-acetyl-piperazino;
• N'-carbethoxy-piperazino;
• N'-benzoyl-piperazino;
• N'-methanesulfonyl-piperazino;
• N'-p-toluenesulfonyl-piperazino;
• N'-carbamoyl-piperazino;
• N'-methyl-piperazino;
• di(alkanol of 2 to 6 carbon atoms)-amino;
• or ethylenediamino;
• and
• R.sub.3 is hydrogen or methyl;
• or a non-toxic, pharmacologically acceptable acid addition salt thereof.