Methyl 2,3-O-(1-methylethylidene)-β-D-ribofuranoside

Colourless Liquid

To a suspension of D-ribose (1; 20.0 g, 133.2 mmol) in acetone (100mL) and MeOH (100 mL) was carefully added conc. H2SO4 (10 mL) at r.t. The resulting solution was stirred for 48 h. After the completion of reaction by TLC monitoring, the solution was neutralized by the addition of solid NaHCO3. The solid was filtered, then the mixture was concentrated, and extracted with EtOAc. The organic layer was dried (MgSO4), filtered, and the solvent was evaporated. The crude product was purified by silica gel flash column chromatography to give the product as a pale yellow oil; yield 24.4 g (90percent); Rf = 0.2 (hexane/EtOAc= 5:1, v/v); [α]D25 –80.00 (c 1.00, CHCl3) {Lit.26 [α]D20 –75.00 (c 1.00, CHCl3)}.1H NMR (CDCl3, 400 MHz): δ = 4.97 (s, 1 H), 4.83 (d, J = 5.7 Hz, 1 H), 4.58 (d, J = 6.0 Hz, 1 H), 4.42 (t, J = 2.7 Hz, 1 H), 3.56–3.72 (m, 2 H), 3.43 (s, 3 H), 3.32 (dd, J = 10.0, 3.0 Hz, 1 H), 1.49 (s, 3 H), 1.32 (s, 3 H).Compound5 was prepared from D-ribose according to literature procedures.A solution of 50.0 g (0.34 mole) of dry D-ribose in 1.0 L of acetone, 100 mL of 2, 2-dimethoxypropane, 200 mL of methanol containing 20 mL of methanol saturated with hydrogen chloride at 0° C. was stirred overnight at room temperature. The resulting solution was neutralized with pyridine and evaporated under reduced pressure. The resulting oil was partitioned between 400 mL of water and 400 mL of methylene chloride. The water layer was extracted twice with methylene chloride (400 mL). The combined organic extracts were dried over sodium sulfate and evaporated under reduced pressure. The residue was purified by silica gel column chromatography [cluent: stepwise gradient of methanol (1-2percent) in methylene chloride] to give pure 1 (52.1 g, 75percent) as a yellow syrup. 1H-NMR (CDCl3): δ5.00 (s, 1H, H-1), 4.86 (d, 1H, H-2, J2-3=5.9 Hz), 4.61 (d, 1H, H-3, J3-2=5.9 Hz), 4.46 (t, 1H, H-4, J4-5=2.7 Hz), 3.77-3.61 (m, 2H, H-5 and H-5'), 3.46 (s, 1H, OCH3), 3.0-2.4 (br s, 1H, OH-5), 1.51 (s, 3H CH3), 1.34 (s, 3H CH3); MS (matrix GT): FAB>0 m/z 173 (M-OCH3)+.A solution of 50.0 g (0.34 mol) of dehydrated D-ribose in acetone (1.0 liter), 2, 2-dimethoxypropane (100 mL), methanol (20 mL) containing 20 mL of methanol saturated with hydrogen chloride at 0 ° C. And the mixture was stirred overnight at room temperature. The resulting solution was neutralized with pyridine and the solvent was distilled off under reduced pressure. The resulting oil was fractionated between 400 mL of water and 400 mL of methylene chloride. The aqueous layer was extracted twice with methylene chloride (400 mL). The combined organic extracts were dried over anhydrous sodium sulfate and the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography [eluent: methanol (1percent to 2percent) / stepwise gradient of methylene chloride] to give pure 1 (52.1 g, 75percent) as a yellow syrup.For 3000 ml three-mouth bottle adding 300gD - ribose, 1040 ml acetone, 1040 ml methanol, 30 ml concentrated hydrochloric acid, stirring and heating to reflux. Keep the backflow reaction 3h, cooling to room temperature, adding 450 ml purified water, saturated Na1) Obtaining Methyl 2, 3-O-isopropyliden-β-D-ribofuranoside (5) A suspension of D-ribose (4, 10g) in acetone (80 mL) cooled to 0°C was added drop by drop to 2, 2-dimethyoxypropane (20 mL) with perchloric acid 70percent (4 mL). It was stirred for two hours at ambient temperature and then methanol (14 mL) was added and the mixture was stirred at ambient temperature for 16 hours. A saturated solution of Kb. AcCl(95 µL, 1.33 mmol) was addeddropwise to a solution of d-ribose(2.00 g, 13.33 mmol) in MeOH (8.0 mL) and Me

Molecular Weight:204.22
XLogP3:-0.4
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:5
Rotatable Bond Count:2
Exact Mass:204.09977361
Monoisotopic Mass:204.09977361
Topological Polar Surface Area:57.2
Heavy Atom Count:14
Complexity:217
Undefined Atom Stereocenter Count:4
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes