NOUVELLES PYRAZOLO (1,5A) PYRIMIDINES ET LEUR PROCEDE DE PREPARATION

1412017 Pyrazolo[1,5-a]pyrimidines ICN PHARMACEUTICALS Inc 1 Dec 1972 [9 Dec 1971 20 April 1972 20 July 1972 24 Oct 1972] 55587/72 Heading C2C The invention comprises compounds of formula wherein R 1 is H, alkoxycarbonyl, alkyl, CN, halogen, carbamoyl, acyl, aminomethyl, dialkylaminomethyl, N0 2 , NH 2 or AcNH; R 2 is alkyl, alkoxy (C 1-8 ), alkylthio (C 1-6 ), SH, cyclic amino or NH 2 (mono- or di-alkyl or otherwise substituted); R 3 is H; and R 4 is H, alkyl or Ph, provided that if (i) R 2 =R 4 =Me, then R 1 is not H or CO 2 Et; (ii) R 4 =Me and R 2 =MeO or EtO, then R 1 is not H; (iii) R 2 = Me, then R 4 and R 1 are not both H, and (iv) R 2 = N 2 H 3 and R 4 = Ph, then R 1 is not H. In examples, these compounds are prepared by reacting a 3-amino-4- R 1 -pyrazole with the dicarbonyl compound R 4 COCH 2 COR 2 , or using standard procedures to introduce into, or to modify or change a substituent element or group in, a preformed pyrazolo-pyrimidine (e.g. one containing a 7-Cl or 7-HO substituent). Also prepared is the starting material EtCH(CN)CHO. Therapeutic compositions having phosphodiesterase enzyme-inhibiting activity, and which in certain cases produce ADP-induced platelet aggregation inhibition and antinauseant or antipregnancy effect, or anti-oedema effect, muscle relaxation, inhibition of ulcer formation, a positive isotropic effect on the heart, an anticonvulsant effect, lowered blood pressure, coronary dilation and/or other cardiovascular activity, comprise compounds of the above formula. The oral and parenteral routes of administration are mentioned.