Pyrimido4,5-d pyrimidine derivatives for use as bronchodilators

Abstract From the Canadian patent

Compounds of the formula (1) :, (see fig.I) or pharmaceutically acceptable salts are described wherein R1 is C1-6alkyl, C2-6alkenyl, C3-5cycloalkylC1-6-alkyl or C1-6alkyl substituted by 1 to 6 fluoro groups; R2 is C1-6alkylthio, C1-6alkylsulphonyl, C1-6alkoxy hydroxy, hydrogen, hydrazino, C1-6alkyl phenyl, -NHCOR3 wherein R3, is hydrogen or C1-6alkyl or -NR4R5, wherein R4 and R5, together with the nitrogen atom to which they are attached form a pyrrolidino, piperidino, hexahydroazepino morpholino, or piperazino ring, or R4 and R5 are independently hydrogen, C3-5cycloalkyl or C1-6alkyl which is optionally substituted by -CF3, phenyl, -S(O)nC1-6alkyl wherein n is 0 1 or 2, -OR6, -CO2R7 or …