SYNTHESIS OF SOME NEW CONDENSED PYRIMIDINES - THIENOPTERIDINE AND PURINE DERIVATIVES

7-Hydroxypteridine (3) and its isomeric 6-hydroxypteridine (4) were prepared by condensation of 5,6-diaminouracil (1) with ethyl thienoylpyruvate (2) in pyridine and hydrochloric acid, respectively. Compounds 3 and 4 were converted into the corresponding thienopteridines 8 and 9 upon treatment with phosphorus pentasulphide. The synthesis of pteridines 12 and 13 was achieved from nitrosouracil (10). Also, the purine 15 and condensed purine 18 were prepared.