The Photocycloaddition Reactions of Uridine and Related Compounds with 2, 3-Dimethyl-2-butene

Abstract

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.