کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5276657 | 1385562 | 2007 | 4 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Synthesis of 4â²-thionucleosides by 1,3-dipolar cycloadditions of the simplest thiocarbonyl ylide with alkenes bearing electron-withdrawing groups Synthesis of 4â²-thionucleosides by 1,3-dipolar cycloadditions of the simplest thiocarbonyl ylide with alkenes bearing electron-withdrawing groups](/preview/png/5276657.png)
Reactions of the simplest thiocarbonyl ylide with a variety of appropriate alkenes bearing electron-withdrawing substituents afforded the corresponding tetrahydrothiophenes, which could be easily elaborated into hydroxy and hydroxymethyl derivatives and then coupled with nucleobases to produce different 4â²-thionucleosides. Particularly, α- and β-anomers of 1-[3,4-bis(hydroxymethyl)tetrahydro-2-thienyl]-thymine, -cytosine, -uracil and -fluorouracil were prepared with dimethyl fumarate and maleate, while 1-[4-(hydroxymethyl)tetrahydro-2-thienyl]- and 1-[4-(hydroxymethyl)tetrahydro-3-thienyl]-thymine, -cytosine, -uracil and -fluorouracil were prepared with a chiral α,β-unsaturated amide. These processes, simple in the experimental conditions and large availability of the starting materials, affording moderate to good yields of 4â²-thionucleosides, represent an optimum alternative to those, already known, based on sugars, which often have the drawbacks of a higher number of steps and lower yields.
Journal: Tetrahedron Letters - Volume 48, Issue 28, 9 July 2007, Pages 4915-4918