Hypoxanthine-guanine-xanthine phosphoribosyltransferase (HGXPRT) is a key enzyme of the purine salvage pathway and its activity is crucial for the survival of certain parasites e.g. Plasmodium falciparum (Pf). Acyclic nucleoside phosphonates (ANPs) containing either guanine or hypoxanthine as the purine base are inhibitors of this enzyme. In this part of a SAR study, these two naturally-occurring nucleobases
次黄嘌呤-
鸟嘌呤-
黄嘌呤磷酸(
HGXPRT)是
嘌呤补救途径的关键酶,其活性是对某些寄生虫生存至关重要例如。恶性疟原虫(Pf)。含有
鸟嘌呤或
次黄嘌呤作为
嘌呤碱基的无环核苷
膦酸酯(ANP)是该酶的
抑制剂。在
SAR研究的这一部分,这两个与无环部分连接的天然存在的碱基被别
嘌呤醇或favipiravir取代。通过Mitsunobu反应制备别
嘌呤醇和favipiravir ANP。法维
吡韦的烷基化被优化以产生N-和O-区域异构体,但是N-区域异构体在去保护条件下不稳定。因此,只有含有Favipiravir的O-异构体的ANP和含有别
嘌呤醇的ANP被评估为人类
HGPRT和Pf
HGXPRT的潜在
抑制剂。以
别嘌醇为基础的两个ANP的Pf的K i值为10μM和30μM
HGXPRT,但在100–150μM的浓度下不抑制人类
HGPRT活性。