Both cis (6) and trans (7) isomers of 6-alkoxy-5-fluoro-5, 6-dihydrouracils were prepared by catalytic hydrogenolysis of t-6-alkoxy-r-5-halogeno-5-fluoro-5, 6-dihydrouracils (4 and 5). The structures were estimated by comparing coupling constants (JH6F) in the proton magnetic resonance (PMR) spectra and confirmed by a single-crystal X-ray analysis of cis-6-ethoxy-5-fluoro-5, 6-dihydrouracil (6a). The stereochemistry of 6-alkoxy-5-alkoxycarbonyl-5-fluoro-5, 6-dihydrouracils (11-13) was clarified similarly on the basis of the PMR data. The chemical behavior of these compounds in acidic and basic media was examined.
通过催化氢解 t-6-alkoxy-r-5-halogeno-5-fluoro-5, 6-dihydrouracils (4 和 5),制备了 6-烷氧基-5-
氟-5, 6-二氢尿
嘧啶的顺式 (6) 和反式 (7) 异构体。通过比较质子磁共振(PMR)光谱中的耦合常数(JH6F)来估计其结构,并通过对顺式-6-乙氧基-5-
氟-5, 6-二氢尿
嘧啶(6a)进行单晶 X 射线分析来确认其结构。根据 PMR 数据,6-烷氧基-5-烷氧羰基-5-
氟-5, 6-二氢尿
嘧啶(11-13)的立体
化学也得到了类似的澄清。研究还考察了这些化合物在酸性和碱性介质中的
化学行为。