REFERENCES
- Wandzik , I. and Bieg , T. 2007 . “ Adducts of uridine and glycals as potential substrates for glycosyltransferases ” . In Bioorg. Chem. Vol. 35 , 401 – 416 .
- Bolitt , V. , Mioskowski , Ch. , Lee , S.-G. and Falck , J.R. 1990 . Direct preparation of 2-deoxy-D-glucopyranosides from glycals without Ferrier rearrangement . J. Org. Chem. , 55 : 5812 – 5813 .
- Maguire , A.R. , Hladezuk , I. and Ford , A. 2002 . New methods for the synthesis of N-benzoylated uridine and thymidine derivatives; a convenient method for N-debenzoylation . Carbohydr. Res. , 337 : 369 – 372 .
- Johnson , D.C. II and Widlanski , T.S. 2004 . Facile Deprotection of O-Cbz-Protected Nucleosides by Hydrogenolysis: An Alternative to O-Benzyl Ether-Protected Nucleosides . Org. Lett. , : 4643 – 4646 .
- Pearlman , W.M. 1967 . Noble metal hydroxides on carbon nonpyrophoric dry catalysts . Tetrahedron Lett. , 17 : 1663 – 1664 .
- Bar , N.C. , Patra , R. , Achari , B. and Mandal , S.B. 1997 . An Entry to Unusual Classes of Nucleoside Analogues . Tetrahedron , 53 : 4727 – 4738 .
- Reitz , G. and Pfleiderer , W. 1975 . Synthese und Eigenschvaften von O′-benzyl-substituierten Diuridylphosphaten . Chem. Ber. , 108 : 2878 – 2894 .
- Bieg , T. and Szeja , W. 1990 . Regioselective hydrogenolysis of benzyl glycosides . Carbohydr. Res. , 205 : c10 – c11 .
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- Procedure for the carbamoylation of uridine (Scheme 3): Trityl chloride (1.37 g, 4.91 mmol) was added to a solution of uridine (1.00 g, 4.09 mmol) in pyridine (5 mL) and reaction mixture was kept at room temperature. After 4 days, the reaction mixture was diluted with CH2Cl2 (300 mL), washed with water (2 × 100 mL), the organic layer was separated, dried (MgSO4), concentrated in vacuo and co-evaporated with toluene (3 × 100 mL). Crude 5′-O-trityluridine (13) was dissolved in CH2Cl2 (15 mL), DIPEA (4.05 ml, 24.54 mmol) was added and solution was cooled to 10°C. A CbzCl (3.50 mL, 24.54 mmol) was added dropwise and the mixture was refluxed for 0.5 hour. The mixture was diluted with CH2Cl2 (100 mł) and washed with 1 M HCl and then water. The organic phase was dried (MgSO4) and concentrated. The residue was dissolved in acetonitrile (10 mL) and 48% HBF4 (0.65 mL, 4.09 mmol) was added. The reaction mixture was kept at room temperature for 1 hour, neutralised with NaHCO3, dried (MgSO4), concentrated and purifi
- Felix , A.M. , Heimer , E.P. , Lambros , T.J. , Tzougraki , C. and Meienhofer , J. 1978 . Rapid Removal of Protecting Groups from Peptides by Catalytic Transfer Hydrogenation with 1,4-Cyclohexadiene . J. Org. Chem. , 43 : 4194 – 4196 .
- Procedure for final O-Cbz, N-Cbz and O-Bn deprotection (Scheme 1, procedure d): To a solution of 8 (109 mg, 0.10 mmol) in MeOH (10 mL) 1,4-cyclohexadiene (0.6 mL) and Pearlman's catalyst (75 mg) were added. Reaction mixture was stirred at room temperature overnight. After removal of the catalyst by filtration crude product were purified by column chromatography with CHCl3/MeOH 10:1 → 5:1 (v/v) solvent system to yield 3 (35 mg, 90%) as a white solid. Compound 3 was prepared using protected uridine 14 and glucal 4 according to previously described procedure.[1]
- Analytical data for new compounds: 5′-O-(2-deoxy-a-D-glucopyranosyl)uridine, 3: solid; [α]D 20+36.0 (MeOH, c 1.0); 1H NMR (300 MHz, CD3OD): δ 1.70 (ddd, 1H, J 3.5, 11.8, 13.2 Hz, H-2′′ax), 2.09 (ddd, 1H, J 1.1, 5.0, 13.2 Hz, H-2′′eq), 3.26 (t, 1H, J 9.0 Hz, H-4′′), 3.53 (ddd, 1H, J 2.3, 5.6, 9.0 Hz, H-5′), 3.67–3.74 (m, 2H, H-6′′a,b), 3.79 (ddd, J 5.0, 9.0, 11.8 Hz, H-3′′), 3.83 (dd, 1H, J 2.3, 11.5 Hz, H-5′a), 3.94 (dd, 1H, J 2.6, 11.5 Hz, H-5′b), 4.12–4.19 (m, 3H, H-2′, 3′, 4′), 4.99 (br d, 1H, J 3.2 Hz, H-1′′), 5.80 (d, J 8.2 Hz, H-5), 5.88 (d, 1H, J 4.1 Hz, H-1′), 7.98 (d, 1H, J 8.2 Hz, H-6); 13C NMR: δ 38.86 (C-2′′), 62.87, 67.11, 69.99, 71.32, 73.21, 74.53, 76.12, 84.46 (C-2′, C-3′, C-4′, C-5′, C-3′′, C-4′′, C-5′