The photochemical reactions of uracil and 5-fluorouracil derivatives with simple alkenes have been investigated. Photocycloaddition of uracil or 5-fluorouracil derivatives and 2, 3-dimethyl-2-butene in acetone gave an enantiomeric mixture of cross cycloadducts (4, 7) in moderate yields. Under similar conditions, diastereomers of 4-substituted 7, 7, 8, 8-tetramethyl-cis-2, 4-diazabicyclo[4.2.0]octane-3, 5-dione nucleosides (14-17) were formed from uridine or 5-fluorouridine derivatives in good yields. The structures and stereochemistry of these cycloadducts of the nucleoside series were elucidated on the basis of the proton nuclear magnetic resonance spectra and X-ray crystallographic analysis.
研究了尿
嘧啶和 5-
氟尿
嘧啶衍
生物与简单烯烃的光
化学反应。尿
嘧啶或5-
氟尿
嘧啶衍
生物与2, 3-二甲基-
2-丁烯在
丙酮中进行光环加成,以中等产率得到交叉环加合物(4, 7)的对映体混合物。在相似的条件下,由
尿苷或5形成4-取代的7,7,8,8-四甲基-顺-2,4-二氮杂
双环[4.2.0]辛烷-3,5-二酮核苷(14-17)的非对映体。 -
氟尿苷衍
生物的收率良好。基于质子核磁共振谱和X射线晶体学分析,阐明了这些核苷系列环加合物的结构和立体
化学。