methyl 3-oxocyclopentane-1-carboxylate

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 318.36 g (3 mol) of trimethylorthoformate are added gradually to a solution of 128.2 g (1 mol) of nonracemic 3-oxocyclopentanecarboxylic acid and 11.4 g (0.06 mol) of p-toluene sulfonic acid hydrate in 380 ml of methanol within 5-10 minutes while stirring, The mixture is heated and during 25 minutes a mixture of formic acid methyl ester and methanol is distilled off (about 185 g of distillate), Thereafter 29 g of 30% sodium methylate solution (0.16 mol) are added and the reaction mixture is kept boiling under reflux for 2 hours; methanol is distilled off, the residue cooled to 10° C. and dissolved by adding 230 ml of methylene chloride and 200 ml of water. By adding 5% sulfuric acid the mixture is adjusted to pH 1.4 and stirred at 10° C. for 30 minutes. The methylene chloride phase is separated and the aqueous phase extracted again with 100 ml of methylene chloride. The combined organic phases are stirred with 50 ml of water, separated and the solvent is distilled off in vacuo. The residue is fractionated in vacuo. The mixture is heated and during 25 minutes is distilled off (about 185 g of distillate) under reflux for 2 hours methanol is distilled off dissolved by adding 230 ml of methylene chloride and 200 ml of water By adding 5% sulfuric acid the mixture stirred at 10° C. for 30 minutes The methylene chloride phase is separated the aqueous phase extracted again with 100 ml of methylene chloride The combined organic phases are stirred with 50 ml of water separated the solvent is distilled off in vacuo

Conditions: temp:23.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of methyl 3-oxocyclopentanecarboxylate (9.58 g, 67.5 mmol) in THF (100 ml) was added to a slurry of sodium borohydride (3.8 g, 100 mmol) in THF (100 ml). The mixture was stirred at 23° C. for 2 h, cooled to 0° C. and acidified to pH 6 with 1M hydrochloric acid. The mixture was extracted with EtOAc (2×100 ml) and the organic extracts were washed with water and saturated sodium chloride (100 ml each). The extracts were dried and the solvent was evaporated in vacuo to give the title compound as a colorless liquid, 6.66 g (68% yield), (a mixture of two isomers); ir (liq.) νmax : 3450, 1725 cm-1 : 1Hmr (CDCl3) δ: 4.30 (m, 1H, H-3), 3.70-3.67 (2×s, 3H, OMe), 2.9 (m, 1H, H-1), 2.8 (s, 1 H, OH) and 2.3-1.6 ppm (m, 6H, CH2). cooled to 0° C. The mixture was extracted with EtOAc (2×100 ml) the organic extracts were washed with water and saturated sodium chloride (100 ml each) The extracts were dried the solvent was evaporated in vacuo

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 3-oxocyclopentanecarboxylic acid (13.2 g, 103 mmol), MeOH (130 ml) and 98% sulfuric acid (0.1 ml) was heated under reflux with stirring for 1.5 h. The MeOH was evaporated in vacuo. The residue was dissolved in CH2Cl2 (100 ml) and was washed with 1% sodium bicarbonate (50 ml). The solvent was evaporated in vacuo to give the title compound as a liquid, 12.2 g (84% yield); ir (liq.) νmax : 1730-1740 cm-1 ; 1Hmr (CDCl3) δ: 3.71 (s, 3H, OMe), 3.2 (m, 1H, H-1) and 2.5-1.9 ppm (m, 6H, CH2). under reflux The MeOH was evaporated in vacuo The residue was dissolved in CH2Cl2 (100 ml) was washed with 1% sodium bicarbonate (50 ml) The solvent was evaporated in vacuo

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 2.8 g of 3-oxocyclopentanecarboxylic acid in 20 ml of diethyl ether was added ethereal solution of diazomethane under cooled with ice until the mixture turned pale yellow, and then the reaction mixture was concentrated under reduced pressure to give about 3.1 g of 3-oxocyclopentanecarboxylic acid methyl ester as crude product. Obtained methyl ester compound was dissolved in 20 ml of methanol and after the mixture was cooled to -50° C., 820 mg of sodium borohydride was added thereto at a time and the mixture was stirred for 20 minutes at the same temperature. After 1.3 ml of acetic acid was dropped slowly to the reaction mixture, methanol was removed under reduced pressure. To the residue was added 10 ml of water and the mixture was extracted with ethyl acetate and the extract was washed successively with water and a saturated aqueous solution of sodium chloride and dried over anhydrous magnesium sulfate and concentrated under reduced pressure to give 3 g of the title compound as crude product having the following physical data. under cooled with ice until the mixture the reaction mixture was concentrated under reduced pressure

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Sodium borohydride (442.6 mg, 11.70 mmol) was added portionwise to a solution of methyl 3-oxocyclopentane-carboxylate A-10 (1.66 g, 11.70 mmol) in absolute ethanol (42.0 mL) at 0° C. The reaction mixture was allowed to warm to room temperature and stirred for 90 mins, then quenched slowly with a 1 N aqueous solution of hydrogen chloride (10 mL), and concentrated to ca. 15 mL under reduced pressure. The aqueous layer was extracted with methylene chloride (3×50 mL); the combined extracts were dried over anhydrous magnesium sulfate, filtered and concentrated to dryness under reduced pressure to give crude methyl 3-hydroxycyclopentanecarboxylate A-11 as a yellow oil (1.33 g, Yield=79%). This material was used for next step without purification. MS (ESI), [M+1]+ 145. at 0° C quenched slowly with a 1 N aqueous solution of hydrogen chloride (10 mL) concentrated to ca. 15 mL under reduced pressure The aqueous layer was extracted with methylene chloride (3×50 mL) the combined extracts were dried over anhydrous magnesium sulfate filtered concentrated to dryness under reduced pressure

Conditions: temp:10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 318.36 g (3 mol) of trimethylorthoformate are added gradually to a solution of 128.2 g (1 mol) of nonracemic 3-oxocyclopentanecarboxylic acid and 11.4 g (0.06 mol) of p-toluene sulfonic acid hydrate in 380 ml of methanol within 5-10 minutes while stirring, The mixture is heated and during 25 minutes a mixture of formic acid methyl ester and methanol is distilled off (about 185 g of distillate), Thereafter 29 g of 30% sodium methylate solution (0.16 mol) are added and the reaction mixture is kept boiling under reflux for 2 hours; methanol is distilled off, the residue cooled to 10° C. and dissolved by adding 230 ml of methylene chloride and 200 ml of water. By adding 5% sulfuric acid the mixture is adjusted to pH 1.4 and stirred at 10° C. for 30 minutes. The methylene chloride phase is separated and the aqueous phase extracted again with 100 ml of methylene chloride. The combined organic phases are stirred with 50 ml of water, separated and the solvent is distilled off in vacuo. The residue is fractionated in vacuo. The mixture is heated and during 25 minutes is distilled off (about 185 g of distillate) under reflux for 2 hours methanol is distilled off dissolved by adding 230 ml of methylene chloride and 200 ml of water By adding 5% sulfuric acid the mixture stirred at 10° C. for 30 minutes The methylene chloride phase is separated the aqueous phase extracted again with 100 ml of methylene chloride The combined organic phases are stirred with 50 ml of water separated the solvent is distilled off in vacuo