Abstract
A series of ribofuranosyl- and 2-deoxyribofuranosyl homo- and spacered-C-nucleosides have been synthesized by reaction of fully protected 3-(1-deoxy-β-D-ribofuranosyl-1-yl)propanal (1), 3-(1,2-dideoxy-β-D-ribofuranos-1-yl)propanal (14), 1-(1-desoxy-β-D-ribofuranos-1-yl)pent-4-yn- 3-on (19), 1-(1-desoxy-β-D-ribofuranos-1-yl)-5-phenyl-pent-4-yn-3-on (20), 1-(1,2-didesoxy-β- D-ribofuranos-1-yl)pent-4-yn-3-on (29), and 1-(1,2-didesoxy-β-D-ribofuranos-1-yl)-5-phenyl- pent-4-yn-3-on (30) with different nucleophiles. The preparation of 1 and 14 proceeds by Knoevenagel reaction with malononitrile, cyanoacetamide and 2-cyano-N-(4-methoxy- phenyl)acetamide and subsequent cyclization with sulphur to thiophenes 5, 7, 8, 16 and then by cyclization with triethyl orthoformate to give thienopyrimidine 6 and thienopyrimidinone 9, 10, and 17. Treatment of acetylenic ketones 19, 20, 29, and 30 with acetamidinium chloride, benzamidinium chloride, and S-methylisothiouronium sulphate provided the corresponding pyrimidines 21-26, 31, 32. Finally, the use of 4H-1,2,4-triazol-3-amine and 2-aminobenz- imidazole as 1,3-N,N'-dinucleophiles afforded the triazolopyrimidines 35, 39 and the pyrimidobenzimidazoles 36, 37, and 40, respectively. Deprotection of a selected number of C- nucleosides was achieved by one or two steps procedure without serious problems. That makes these C-nucleosides promising candidates for the synthesis of monomers suitable for solid phase nucleic acid oligomerization.
Highlights
The interest in nucleoside analogues is unbroken and their design and synthesis have been done with quite different intentions e.g. synthesis of homo-C-nucleosides with potential biological activity,[1,2,3] tools for elucidating the structural and functional properties of damaged DNA,[4] illustration of hybridizations and conformational changes of DNA and RNAs,[5] and to give an answer to the question why DNA evolved on Earth to have the structure that it does.[6,7,8,9,10]
Pursuing a program directed at the synthesis of homo-C-nucleosides, we have described previously an efficient route for the preparation of β-allyl C-glycosides of D-ribofuranose and 2deoxy-D-ribofuranose.[11]
In this contribution we present our results on transformation of the furnished aldehydes (1,14) and acetylenic ketones (19, 20, 29, 30) as versatile intermediates into a selected number of different heterocycles to make the synthetic potential of these precursors visible
Summary
The interest in nucleoside analogues is unbroken and their design and synthesis have been done with quite different intentions e.g. synthesis of homo-C-nucleosides with potential biological activity,[1,2,3] tools for elucidating the structural and functional properties of damaged DNA,[4] illustration of hybridizations and conformational changes of DNA and RNAs,[5] and to give an answer to the question why DNA evolved on Earth to have the structure that it does.[6,7,8,9,10]. In this contribution we present our results on transformation of the furnished aldehydes (1,14) and acetylenic ketones (19, 20, 29, 30) as versatile intermediates into a selected number of different heterocycles to make the synthetic potential of these precursors visible
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
