Nucleosides 3¹: Synthesis of novel 1,3,4-oxadiazole nucleosides

Abstract

5-Aryl-1,3,4-oxadiazole-2(3H)-thiones are ribosylated by reaction with 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose, followed by debenzoylation, to give novel 1,3,4-oxadiazole nucleosides in good yields, one of which reacted with aniline to yield the corresponding 3,4-diaryl-1,2,4-triazole nucleoside.

Synthesis of the Novel 3-Benzotriazole-5-yl difluoromethyl-5-trifluoromethyl benzotriazole Nucleosides

“…1 H NMR spectra of (7) and (8) showed in each case a doublet signals at δ 6.67, 6.73 for compound (7) and at δ 6.74, 6.67 for compound (8) assigned to the anomeric proton of the ribose moiety with spin-spin coupling constant (J 1',2' ) and (J 1'',2'' ) equal to 7.5 Hz, which confirms the β-anomeric configuration. While confirms the a-anomeric configuration showed spin-spin coupling constant (J 1',2' ) and (J 1'',2'' ) equal to 3.4 Hz, which confirms the a-anomeric configuration for compound (8) (Mosselhi, 1993;Mosselhi, 1999;Mosselhi & Seliger, 2001;Mosselhi & Break, 2011;Break et al, 2010;Metwally et al, 2010;Breaket al, 2013 andKhalil, 2006). The 1 H NMR spectra of nucleosides free showed a doublet signals at δ 6.41, 6.46 for compound (9) spinspin coupling constant (J 1',2' ) and (J 1'',2'' ) equal to 7.5 Hz -anomeric configuration and at δ 6.43, 6.47 for compound (10) assigned to spin-spin coupling constant (J 1',2' ) and (J 1'',2'' ) equal to 4.25 Hz, which confirms the a-anomeric configuration.…”

Synthesis of Some New S-Nucleoside Derivatives of 2-Thioxo and (2,4-Dithioxo)-5,6,7,8-Tetrahydrobenzo-Thieno[2,3-d]Pyrimidin-4-(3H)Ones

“…This is in accord with the results for other 2,3,5-tri-O-benzoyl-1-β-D-furanosyl pyrimidine and purine nucleosides. 20,[22][23][24] The 13 C NMR of nucleoside products revealed the absence of a thione carbon atom at about δ 173.0 for product 3 and at δ 169.0, 181.0 for product 4. The resonance of the N C N carbon atom (C2) of 3 at δ 159.0 was similar to the chemical shift of the corresponding carbon atom of compound 1a.…”

“…4,5 Other differently substituted thieno[2, 3-d]pyrimidine nucleosides as antiviral agents against hepatitis-A virus (HAV) have been recently described. 6 In light of these considerations and in continuation of the studies in the chemistry of nucleosides and thieno[2, 3-d]pyrimidine, [7][8][9][10][11][12][22][23][24] we thought it interesting to investigate the synthesis of some new nucleosides of thieno[2, 3-d]pyrimidine.…”

Synthesis, structure and antimicrobial evaluation of new derivatives of theophylline sugar hydrazones

“…In view of the biological importance of theophylline derivatives, sugar hydrazones and acyclonucleosides and in continuation of our studies on the synthesis of purines and nucleoside derivatives as potential bioactive compounds, [25][26][27] it was considered worthwhile to study the reaction of 7-ethyl-8-hydrazinotheophylline with sugars. Our goal was the synthesis of [1,2,4]triazolo [4,3-e]theophylline derivatives as new acyclo C-nucleosides via theophylline sugar hydrazones and to explore the biological activities of the products.…”