5-(benzyloxy)-4-oxo-4H-pyran-2-carboxylic acid

5-Benzyloxy-2-hydroxymethyl-4H-pyran-4-one (12b) (10.00 g, 43 mmol) was dissolved in acetone (1000 mL). Jones-reagent (25 mL) was added to the solution and the reaction mixture was stirred below 20 °C for 3 h. B. Step 1 : Preparation of C201. A solution of C22 (50.0 g, 215 mmol) and 2, 2, 6, 6- tetramethyl-piperidin-1 -oxyl (2.40 mL, 15.1 mmol) in acetonitrile (850 mL) at 20 °C in a three neck round bottom was treated with a 0.67M sodium phosphate buffer (600 mL of 1 :1 mixture of 0.67M sodium dihydrogen phosphate and 0.67M sodium hydrogen phosphate = pH 6.7). A solution of sodium chlorite was prepared by dissolving 80percent sodium chlorite (48.7 g) in water (180 mL) and a dilute solution of sodium hypochlorite was prepared by diluting bleach (5.25percent sodium hypochlorite, 4.31 mmol, 6.10 mL) in water (100 mL). The reaction mixture was heated to 35 °C and the dilute sodium chlorite and dilute bleach solutions were added via addition funnels 10percent at a time over 20 minutes. After complete addition, the reaction was cooled to ambient temperature and diluted with water (150 mL). The pH was adjusted to 8.0 with addition of 2. ON sodium hydroxide (approximately 100 mL). The mixture was poured into a sodium sulfite solution (54.0 g in 800 mL water) while maintaining a temperature of < 20 °C. After 30 minutes the mixture was extracted with methyl tert-butyl ether. The organic layer was discarded and the aqueous layer was acidified with 2. ON hydrochloric acid (approximately 200 mL) to pH = 2 resulting in a white precipitate. The precipitate was collected via filtration to afford C201 as a white solid. Yield: 39.8 g, 161 mmol, 75percent. LCMS m/z 247.3 (M+1 ). A 5-benzyloxy-4-oxo -4H-pyran-2-carboxylic acid preparation method, firstly the 90g kojic acid is added to 2000 ml of the flask, add 660 ml of methanol to dissolve the kojic acid, then adding 88g benzyl chloride and 63 ml of 40percent alkali solution, heating reflux reaction 17 hours to obtain a reaction liquid a; reduced pressure distillation of the reaction liquid, until the solvent is distilled to stop evaporation to dryness, then cooling to normal temperature; and then in to the distillation of the remaining substances by adding 60 ml, and a 240 ml water, to stir, washing, filtering, drying the obtained solid, get 116g yellowish solid is intermediate; the 116g intermediate is added to the reactor, then adding 2000 ml water, reduce the temperature to -5 °C, high sodium iodate, to control the temperature is not higher than 5 °C, after adding, dripping 40 ml of water, stirring 10 minutes, the temperature is increased to 17 °C, stirring for 3 hours to obtain a reaction liquid; filtering the obtained reaction solution, the filtrate is adjusted with hydrochloric acid PH value is 5-6, with 500g the ethyl acetate extraction, layered, drying, filtering, drying the obtained solid, get 80g white solid is 5-benzyloxy-4-oxo -4H-pyran-2-carboxylic acid.Compound 8 (0.50 g, 2.03 mmol) and sodiumiodide (0.457 g, 3.05 mmol) were dissolved in dry MeCN (40 mL) under argon and trimethylsilylchloride (370 mL, 3.05 mmol) was added. The solution first stirred at 70 Cfor 5.5 h. Then, H2O (100 mL) was added and the mixture was extracted with MTBE (2x 20 mL) and then with CH2Cl2 (4 x 20 mL). The aqueous layer was concentrated bythree-quarters under reduced pressure and the pH of the solution was adjusted to 1 withconcentrated HCl. The solution was left at room temperature until crystals were formed.The brownish crystals were collected, recrystallized from 50% aqueous ethanol anddried in vacuo to give compound 2 (0.29 g, 92%). mp 286 C; IR (ATR, cm1): 3329, 3085, 2838, 2552, 1725, 1628, 1559, 1536, 1219, 1201, 1142, 1098, 936, 905, 760; 1HNMR (DMSO-d6): d (ppm)6.95 (s, 1H, H3), 8.19 (s, 1H, H6); 13C NMR (DMSOd6):d (ppm)116.0 (C3), 140.3 (C5), 147.7 (C6), 152.4 (C2), 160.8 (COOH), 173.7(C4); ASAP (neg.) mass spectrum m/z 154.9975 (calculated for C6H3O5 154.9975). Allcharacterization data matched the literature.21C. Preparation of 5-(benzyloxy)-4-oxo-1, 4-dihydropyridine-2-carboxylic acid (C3). A mixture of C2 (100 g, 0.406 mol) and aqueous ammonium hydroxide solution (25%, 1 L) was stirred in an autoclave for 1 hour, and then heated at 83 C. for 7 hours at atmospheric pressure. After cooling slowly over about 18 hours, the reaction mixture was acidified to pH 3 with concentrated hydrochloric acid. The resulting precipitate was collected by filtration, washed with water, and dissolved in saturated aqueous sodium bicarbonate solution. The solution was washed with dichloromethane, then acidified with concentrated hydrochloride acid. The resulting solid was collected by filtration, washed with water and dried at 50 C. to provide C3. Yield: 85 g, 0.347 mol, 85%. 1H NMR (400 MHz, DMSO-d6) delta 5.17 (s, 2H), 7.17 (br s, 1H), 7.33-7.49 (m, 7H).A 5-(Benzyloxy)-1, 4-dihydro-4-oxo-2-pyridine carboxylic acid A mixture of 5-(benzyloxy)-4-pyrone-2-carboxylic acid (10.92 g, 44.4 mmole) in 35 ml of 95% ethanol and 70 ml of ammonium hydroxide was refluxed for 6 hours. The volatiles were removed in vacuo, the residue was dissolved in water and the pH was lowered to 3 with HCl. The resulting solid was filtered and washed with water. Recrystallization from methanol afforded 9.5 g of the title compound.(C) 1, 4-Dihydro-4-oxo-5-(phenylmethoxy)-2-pyridinecarboxylic acid 300 g (1.22 mol) of

Molecular Weight:246.21
XLogP3:1.5
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:5
Rotatable Bond Count:4
Exact Mass:246.05282342
Monoisotopic Mass:246.05282342
Topological Polar Surface Area:72.8
Heavy Atom Count:18
Complexity:402
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes