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

Abstract

Ribosylation of 2-thioxo-5,6,7,8-tetrahydrobenzo thieno[2,3-d]pyrimidin-4(3H)-one 1a and 2,4-dithioxo-5,6,7,8-tetrahydrobenzo thieno[2,3-d]pyrimidine 1b with 1-O-acetyl-2,3,5-tri-O-benzoyl-β-D-ribofuranose 7 afforded the benzoylated S-nucleoside derivatives 3 and 4, respectively. Debenzoylation of 3 and 4 by using methanolic sodium methoxide yielded the corresponding free S-nucleosides 5 and 6, respectively. Furthermore, the reaction of potassium salt of 2-thioxo-5,6,7,8-tetrahydrobenzo thieno[2,3-d]pyrimidin-4(3H)-one 8 with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide 9, afforded 10. Deacetylation of the latter by using methanolic sodium methoxide yielded the corresponding S-glycoside, 2-(2 ,3 ,4 ,6 -tetra-hydroxy-β-D-glucopyranosylthio)-5,6,7,8-tetrahydro-benzothieno [2,3-d]pyrimidin-4-one 11. The structural elucidation of the new nucleosides formed was reported.

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 8-Trifluloromethyl-2-Thioquinazolin-(3H)-4-One Nucleosides

“…1 H NMR spectra of compound 5 and 6 showed in each case a doublet signals at δ 5.98 (d, 1H, J = 7.5 Hz) H 1`f or compound 5 and at δ 5.17 (d, 1H, J = 7.5 Hz) H 1`f or free nucleoside compound 6 assigned to the anomeric proton of the ribose moiety with spin-spin coupling constant (J 1',2' ) equal to 7.5 Hz, which confirms the β-anomeric configuration. (Break,2017;Break et al, 2014;Break et al, 2013;Break & Mosselhi, 2012;Mosselhi & Break, 2011;Break et al, 2010;Chien T.-C. et al, 2005 andAbdullah Hijazi, 1988). The 1 H NMR of compounds 5 and 6 showed the expected base moiety protons in addition to the sugar moiety protons (see the Experimental section).…”

Synthesis of Some of Fluorinated Benzimidazole Nucleosides

“…While confirms the -anomeric configuration showed spin-spin coupling constant (J 1',2' ) equal to 6.8 Hz, which confirms the a-anomeric configuration for compound (9), and the spin-spin coupling constant (J 1',2' ) equal to 4.8 Hz, which confirms the -anomeric (12). (Mosselhi & Break, 2011;Break et al, 2010;Break et al, 2013, Break et al, 2014Mosselhi A. N. Mosselhi and Laila M. Break, 2011 H NMR spectra of (10),(11) and (13) showed in each case a doublet signals at δ 6.06 assigned to the anomeric proton of the ribose moiety with spin-spin coupling constant (J 1',2' ) equal to 8.2 Hz, which confirms the -anomeric configuration (10), showed a doublet signals at  6.75 the spin-spin coupling constant (J 1',2' ) equal to 7.65 Hz, which confirms the -anomeric configuration(11). While -anomeric configuration (12) showed a doublet signals at  4.84, (J 1',2' ) equal to 7.65 Hz.…”