4-SUBSTITUTED PYRAZOLOÛ3,4-D¨PYRIMIDINE DERIVATIVES

4-Substituted pyrazolo [3,4-d] pyrimidinyl piperazine derivatives of formula wherein X is selected from S, O, NH, NR1, wherein R1 alkyl; M is selected from CH2, CHOH, CHOCOR2 and CHOR2 wherein R2 is selected from alkyl, phenyl and substituted phenyl; Y is N, N(CH2)n wherein n is 0-4, or a carbon atom having a double bond (C=) attached to the carbon atom to which Ar1, Ar2, and Ar3 are attached. Ar1, Ar2 and Ar3 are independently selected from hydrogen, alkyl, phenyl, substituted phenyl naphthyl, pyridyl and thienyl; Z is selected from H, CN, CO2R3 wherein R3 is H or alkyl; lower alkyl, halogen and OH; R is selected from H, alkyl; cyclopentyl, cyclohexyl, benzyl, alkenyl, alkynyl, tetrahydropyranyl and tetrahydrofuranyl; Q is selected from halo, amino, alkyl and OH; The compounds possess intravenous and/or positive inotropic activity and are useful as cardiovascular agents. The compounds are especially useful as cardiotonic agents for improving cardiac ejection, particularly in the setting of acute or chronic heart failure. The compounds are also useful as antiarrythmic agents for the treatment or prevention of cardiac arrythmias.