Pyrrolidine analogues of C-nucleosides related to pseudouridine have been synthesized by 1,3-dipolar cycloaddition reactions of uracil-5 and 2,4-dimethoxypyrimidine-5 nitrones with allyl alcohol and methyl acrylate, and subsequent reductive cleavage of the isoxazolidine cycloadducts. The dimethoxy derivatives have been easily deprotected to the corresponding uracils bearing the pyrrolidine ring instead
Isoxazole, isoxazoline and isoxazolidine analogues of C-nucleosides related to pseudouridine have been synthesized by 1,3-dipolar cycloaddition reactions of nitrile oxides and nitrones derived from mono and disubstituted uracil-5-carbaldehydes and 2,4-dimethoxypyrimidine-5-carbaldehyde. The dimethoxy derivatives have been easily deprotected to the corresponding uracils bearing the heterocyclic ring
A variety of new 5-alkenyluracils has been prepared in high yields by Wittigolefination of 5-formyl-1-octy-luracil, 5-formyl-1,3-dioctyluracil and 5-formyl-2,4-dimethoxy pyrimidine with stabilized and semistabi-lized phosphorus ylides. The conformation of the products is discussed on the basis of 1H NMR spectral data.
高纯度的各种新的5-烯基尿嘧啶是通过将稳定化的5-甲酰基-1-辛基-尿嘧啶,5-甲酰基-1,3-二辛基尿嘧啶和5-甲酰基-2,4-二甲氧基嘧啶进行Wittig烯化反应而制得的。半稳定的磷化氢。基于1 H NMR光谱数据讨论产物的构象。