ethyl 3-[ethoxycarbonyl-(2-ethoxy-2-oxoethyl)amino]propanoate

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

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

Procedure: A solution of 53.9 g of ethyl N-(ethoxycarbonylmethyl)-N-(ethoxycarbonyl)-β-alaninate in 200 ml of toluene is added dropwise to a stirred solution of potassium hexamethyldisilazide (429 ml, 0,653 M) in 125 ml of toluene under nitrogen and cooled to 0° . After 45 minutes at 0°, 21.6 ml of acetic acid is added followed by a solution of 100 g of sodium phosphate (monobasic) in 1 liter of water. The layers are separated, the organic layer is washed with pH 7 buffer, dried over sodium sulfate, filtered, concentrated and purified by flash chromatography using ethyl acetate/hexane (3:7) to yield ethyl 1-ethoxycarbonyl-3-oxo-pyrrolidine-2-carboxylate. cooled to 0° The layers are separated the organic layer is washed with pH 7 buffer dried over sodium sulfate filtered concentrated purified by flash chromatography

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

Procedure: To a mixture of 49 g of ethyl N-(ethoxycarbonylmethyl)-β-alaninate and 30 ml of water cooled to -10° is added dropwise 27.6 ml of ethyl chloroformate followed by a solution of 12.7 g of sodium carbonate in 50 ml of water. The mixture is warmed to room temperature then heated at 55° for 50 minutes. The mixture is cooled, extracted with toluene, the extract is washed with 2N hydrochloric acid and water. The extract is dried over sodium sulfate, filtered, concentrated and distilled in vacuo to yield ethyl N-(ethoxycarbonylmethyl)-N-(ethoxycarbonyl)-β-alaninate. cooled to -10° then heated at 55° for 50 minutes The mixture is cooled extracted with toluene the extract is washed with 2N hydrochloric acid and water The extract is dried over sodium sulfate filtered concentrated distilled in vacuo

Conditions: temp:80.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Intermediate (e) (18.0 g, 65.2 mmol) was added to an ice bath cooled solution of NaOEt (32.6 mL) (21% by weight in EtOH) in absolute EtOH (41.7 mL) under a nitrogen atmosphere. The ice bath was removed and the mixture was heated at 80° C. for about 12 h until the condensation was complete as observed by TLC. The mixture was poured onto ice/water and extracted into EtOAc. The solvent was dried with Na2SO4, filtered, and evaporated to afford crude intermediate (f) as an off white solid (14.05 g) which was carried on without purification. The ice bath was removed The mixture was poured onto ice/water extracted into EtOAc The solvent was dried with Na2SO4 filtered evaporated

Conditions: temp:80.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Intermediate (e) (18.0 g, 65.2 mmol) was added to an ice bath cooled solution of NaOEt (32.6 mL) (21% by weight in EtOH) in absolute EtOH (41.7 mL) under a nitrogen atmosphere. The ice bath was removed and the mixture was heated at 80° C. for about 12 h until the condensation was complete as observed by TLC. The mixture was poured onto ice/water and extracted into EtOAc. The solvent was dried with Na2SO4, filtered, and evaporated to afford crude intermediate (f) as an off white solid (14.05 g) which was carried on without purification. The ice bath was removed The mixture was poured onto ice/water extracted into EtOAc The solvent was dried with Na2SO4 filtered evaporated

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

Procedure: Crude intermediate (c) (418 mmol) was dissolved in CH2Cl2 (275 mL) and triethylamine (58.3 mL, 418 mmol) was added followed by ethyl chloroformate (d) (39.8 mL, 418 mmol). The reaction was stirred at ambient temperature for about 24 h. After the reaction was complete, the volatile components were removed under vacuum. The crude product was then distilled under vacuum (about 5 mm Hg) and dissolved in EtOAc which was washed with aqueous saturated KHSO4×3, with brine×1 and dried over Na2SO4. Following filtration, the volatile components were removed under vacuum to afford intermediate (e) as a clear oil (74.8 g, 272 mmol) in 65% yield over two steps. the volatile components were removed under vacuum The crude product was then distilled under vacuum (about 5 mm Hg) dissolved in EtOAc which was washed with aqueous saturated KHSO4×3, with brine×1 dried over Na2SO4 filtration the volatile components were removed under vacuum

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

Procedure: A solution of 53.9 g of ethyl N-(ethoxycarbonylmethyl)-N-(ethoxycarbonyl)-β-alaninate in 200 ml of toluene is added dropwise to a stirred solution of potassium hexamethyldisilazide (429 ml, 0,653 M) in 125 ml of toluene under nitrogen and cooled to 0° . After 45 minutes at 0°, 21.6 ml of acetic acid is added followed by a solution of 100 g of sodium phosphate (monobasic) in 1 liter of water. The layers are separated, the organic layer is washed with pH 7 buffer, dried over sodium sulfate, filtered, concentrated and purified by flash chromatography using ethyl acetate/hexane (3:7) to yield ethyl 1-ethoxycarbonyl-3-oxo-pyrrolidine-2-carboxylate. cooled to 0° The layers are separated the organic layer is washed with pH 7 buffer dried over sodium sulfate filtered concentrated purified by flash chromatography

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

Procedure: To a mixture of 49 g of ethyl N-(ethoxycarbonylmethyl)-β-alaninate and 30 ml of water cooled to -10° is added dropwise 27.6 ml of ethyl chloroformate followed by a solution of 12.7 g of sodium carbonate in 50 ml of water. The mixture is warmed to room temperature then heated at 55° for 50 minutes. The mixture is cooled, extracted with toluene, the extract is washed with 2N hydrochloric acid and water. The extract is dried over sodium sulfate, filtered, concentrated and distilled in vacuo to yield ethyl N-(ethoxycarbonylmethyl)-N-(ethoxycarbonyl)-β-alaninate. cooled to -10° then heated at 55° for 50 minutes The mixture is cooled extracted with toluene the extract is washed with 2N hydrochloric acid and water The extract is dried over sodium sulfate filtered concentrated distilled in vacuo

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

Procedure: To a mixture of 49 g of ethyl N-(ethoxycarbonylmethyl)-β-alaninate and 30 ml of water cooled to -10° is added dropwise 27.6 ml of ethyl chloroformate followed by a solution of 12.7 g of sodium carbonate in 50 ml of water. The mixture is warmed to room temperature then heated at 55° for 50 minutes. The mixture is cooled, extracted with toluene, the extract is washed with 2N hydrochloric acid and water. The extract is dried over sodium sulfate, filtered, concentrated and distilled in vacuo to yield ethyl N-(ethoxycarbonylmethyl)-N-(ethoxycarbonyl)-β-alaninate. cooled to -10° then heated at 55° for 50 minutes The mixture is cooled extracted with toluene the extract is washed with 2N hydrochloric acid and water The extract is dried over sodium sulfate filtered concentrated distilled in vacuo

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

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

Procedure: A solution of 53.9 g of ethyl N-(ethoxycarbonylmethyl)-N-(ethoxycarbonyl)-β-alaninate in 200 ml of toluene is added dropwise to a stirred solution of potassium hexamethyldisilazide (429 ml, 0,653M) in 125 ml of toluene under nitrogen and cooled to 0°. After 45 minutes at 0°, 21.6 ml of acetic acid is added followed by a solution of 100 g of sodium phosphate (monobasic) in 1 liter of water. The layers are separated, the organic layer is washed with pH 7 buffer, dried over sodium sulfate, filtered, concentrated and purified by flash chromatography using ethyl acetate/hexane (3:7) to yield ethyl 1-ethoxycarbonyl-3-oxo-pyrrolidine-2-carboxylate. cooled to 0° The layers are separated the organic layer is washed with pH 7 buffer dried over sodium sulfate filtered concentrated purified by flash chromatography

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

Procedure: To a mixture of 49 g of ethyl N-(ethoxycarbonylmethyl)-β-alaninate and 30 ml of water cooled to -10° is added dropwise 27.6 ml of ethyl chloroformate followed by a solution of 12.7 g of sodium carbonate in 50 ml of water. The mixture is warmed to room temperature then heated at 55° for 50 minutes. The mixture is cooled, extracted with toluene, the extract is washed with 2N hydrochloric acid and water. The extract is dried over sodium sulfate, filtered, concentrated and distilled in vacuo to yield ethyl N-(ethoxycarbonylmethyl)-N-(ethoxycarbonyl)-β-alaninate. cooled to -10° then heated at 55° for 50 minutes The mixture is cooled extracted with toluene the extract is washed with 2N hydrochloric acid and water The extract is dried over sodium sulfate filtered concentrated distilled in vacuo