ETHYL1-METHYL-2-OXOCYCLOPENTANECARBOXYLATE

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

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

Procedure: When the thallous salts of ethyl acetoacetate, 2-carbethoxycyclopentanone, ethyl benzoylacetate, and ethyl 2-methylbenzoylacetate, prepared according to Example 1, are refluxed with methyl iodide as described in Example 1 for periods of about 4, 9, 4, and 14 hours, respectively, ethyl 2-methylacetoacetate (b.p. 82°/25 mm.), 2-methyl-2-carbethoxycyclopentanone (b.p. 124°-126°/35 mm.), ethyl 2-methylbenzoyl acetate (b.p. 96°-97°/0.25 mm.), ), and ethyl 2,2-dimethylbenzoylacetate (b.p. 98°-100°/0.35 mm.), respectively, are obtained in quantitative yield.

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

Procedure: When the thallous salts of ethyl acetoacetate, 2-carbethoxycyclopentanone, ethyl benzoylacetate, and ethyl 2-methylbenzoylacetate, prepared according to Example 1, are refluxed with methyl iodide as described in Example 1 for periods of about 4, 9, 4, and 14 hours, respectively, ethyl 2-methylacetoacetate (b.p. 82°/25 mm.), 2-methyl- 2-carbethoxy-cyclopentanone (b.p. 124°-126°/35 mm.), ethyl 2-methylbenzoyl acetate (b.p. 96°-97°/0.25 mm.), and ethyl 2,2-dimethylbenzoyl-acetate (b.p. 98°-100°/0.35 mm.), respectively, are obtained in quantitative yield.

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

Procedure: When the thallous salts of ethyl acetoacetate, 2-carbethoxycyclopentanone, ethyl benzoylacetate, and ethyl 2-methylbenzoylacetate, prepared according to Example 1, are refluxed with methyl iodide as described in Example 1 for periods of about 4, 9, 4, and 14 hours, respectively, ethyl 2-methylacetoacetate (b.p. 82°/25 mm.), 2-methyl- 2-carbethoxy-cyclopentanone (b.p. 124°-126°/35 mm.), ethyl 2-methylbenzoyl acetate (b.p. 96°-97°/0.25 mm.), and ethyl 2,2-dimethylbenzoyl-acetate (b.p. 98°-100°/0.35 mm.), respectively, are obtained in quantitative yield.

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

Procedure: To a stirred suspension of dry potassium carbonate (16.64 g, 120.4 mmol) in dry acetone (200 mL) under argon was added ethyl 2-oxocyclopentanecarboxylate (9.40 g, 60.2 mmol) followed by methyl iodide (7.5 mL, 120.4 mmol). The reaction was heated to reflux for 3 hours and then another portion of methyl iodide (7.5 mL, 120.4 mmol) was added and the reaction was refluxed overnight. The reaction mixture was cooled and then filtered through a silica gel pad and the solid was washed with acetone (100 mL×3). The organic phase was concentrated under reduced pressure and the residue dispersed in acetone (200 mL) and filtered. The filtrate was concentrated under reduced pressure and the residue was purified by silica gel column chromatography (eluent: petroleum ether/ethyl acetate=100/1->50/1) to afford the title compound as a colorless liquid (8.35 g, Yield: 82%). 1H NMR (400 MHz, CDCl3) δ 4.22-4.10 (m, 2H), 2.57-2.40 (m, 2H), 2.36-2.27 (m, 1H), 2.11-2.00 (m, 1H), 1.98-1.83 (m, 2H), 1.31 (s, 3H), 1.25 (t, J=7.0 Hz, 3H) ppm. The reaction was heated to reflux for 3 hours the reaction was refluxed overnight The reaction mixture was cooled filtered through a silica gel pad the solid was washed with acetone (100 mL×3) The organic phase was concentrated under reduced pressure the residue dispersed in acetone (200 mL) filtered The filtrate was concentrated under reduced pressure the residue was purified by silica gel column chromatography (eluent: petroleum ether/ethyl acetate=100/1->50/1)

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

Procedure: When the thallous salts of ethyl acetoacetate, 2-carbethoxycyclopentanone, ethyl benzoylacetate, and ethyl 2-methylbenzoylacetate, prepared according to Example 1, are refluxed with methyl iodide as described in Example 1 for periods of about 4, 9, 4, and 14 hours, respectively, ethyl 2-methylacetoacetate (b.p. 82°/25 mm.), 2-methyl-2-carbethoxycyclopentanone (b.p. 124°-126°/35 mm.), ethyl 2-methylbenzoyl acetate (b.p. 96°-97°/0.25 mm.), ), and ethyl 2,2-dimethylbenzoylacetate (b.p. 98°-100°/0.35 mm.), respectively, are obtained in quantitative yield.

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

Procedure: When the thallous salts of ethyl acetoacetate, 2-carbethoxycyclopentanone, ethyl benzoylacetate, and ethyl 2-methylbenzoylacetate, prepared according to Example 1, are refluxed with methyl iodide as described in Example 1 for periods of about 4, 9, 4, and 14 hours, respectively, ethyl 2-methylacetoacetate (b.p. 82°/25 mm.), 2-methyl-2-carbethoxycyclopentanone (b.p. 124°-126°/35 mm.), ethyl 2-methylbenzoyl acetate (b.p. 96°-97°/0.25 mm.), ), and ethyl 2,2-dimethylbenzoylacetate (b.p. 98°-100°/0.35 mm.), respectively, are obtained in quantitative yield.

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

Procedure: When the thallous salts of ethyl acetoacetate, 2-carbethoxycyclopentanone, ethyl benzoylacetate, and ethyl 2-methylbenzoylacetate, prepared according to Example 1, are refluxed with methyl iodide as described in Example 1 for periods of about 4, 9, 4, and 14 hours, respectively, ethyl 2-methylacetoacetate (b.p. 82°/25 mm.), 2-methyl- 2-carbethoxy-cyclopentanone (b.p. 124°-126°/35 mm.), ethyl 2-methylbenzoyl acetate (b.p. 96°-97°/0.25 mm.), and ethyl 2,2-dimethylbenzoyl-acetate (b.p. 98°-100°/0.35 mm.), respectively, are obtained in quantitative yield.

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

Procedure: When the thallous salts of ethyl acetoacetate, 2-carbethoxycyclopentanone, ethyl benzoylacetate, and ethyl 2-methylbenzoylacetate, prepared according to Example 1, are refluxed with methyl iodide as described in Example 1 for periods of about 4, 9, 4, and 14 hours, respectively, ethyl 2-methylacetoacetate (b.p. 82°/25 mm.), 2-methyl- 2-carbethoxy-cyclopentanone (b.p. 124°-126°/35 mm.), ethyl 2-methylbenzoyl acetate (b.p. 96°-97°/0.25 mm.), and ethyl 2,2-dimethylbenzoyl-acetate (b.p. 98°-100°/0.35 mm.), respectively, are obtained in quantitative yield.

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

Procedure: Under vigorously agitation, 20.3 g of ethyl 2-oxocyclopentane carboxylate was added to 53.8 g of fine powdery anhydrous potassium carbonate, and after stirring for several minutes, to the mixture was added 90 ml of acetone. The reaction mixture was further stirred for 15 to 30 minutes at room temperature, then to the mixture was dropwise added 36.9 g of methyl iodide. Upon the completion of the addition, the reaction mixture was heated for reflux for 1 hour. The solvent was removed under reduced pressure, and the solid residue was washed with diethyl ether. The washing liquor was collected and washed with water. After removing the solvent, 22.0 g of pale yellow liquid was obtained. The liquid was distilled under reduced pressure, and 20.9 g of colorless liquid as a distillate cut of 131-133° C./39 mmHg was collected. Yield: 94.6%. The reaction mixture was further stirred for 15 to 30 minutes at room temperature Upon the completion of the addition the reaction mixture was heated for reflux for 1 hour The solvent was removed under reduced pressure the solid residue was washed with diethyl ether The washing liquor was collected washed with water After removing the solvent

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

Procedure: To a suspension of ethyl 2-oxocyclopentanecarboxylate (20.3 g, 0.130 mol) and K2CO3 (53.8 g, 0.390 mol) in acetone (90 mL) was added MeI (36.9 g, 0.250 mol) at ambient temperature. The reaction mixture was stirred for 30 min at ambient temperature and then heated under reflux for 1 h. Acetone was removed under reduced pressure and diethyl ether (200 mL) was added to the residue. The resulting mixture was stirred for 15 min and filtered. The filtrate was concentrated under reduced pressure followed by distillation under vacuum to afford ethyl 1-methyl-2-oxocyclopentanecarboxylate (20.5 g, 92% yield). heated under reflux for 1 h Acetone was removed under reduced pressure and diethyl ether (200 mL) was added to the residue The resulting mixture was stirred for 15 min filtered The filtrate was concentrated under reduced pressure followed by distillation under vacuum

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