.alpha. and .beta.-ribonucleosides of substituted pyrimido[5,4-d]pyrimidines are used in treating malignant tumors in vivo. A novel synthesis for preparing these compounds and other related compounds is further disclosed.
取代的
嘧啶并[5,4-d]
嘧啶的.alpha.和.beta.-
核糖核苷酸在体内用于治疗恶性肿瘤。进一步揭示了一种用于制备这些化合物和其他相关化合物的新合成方法。