ethyl 2-(2,2-dimethylpropanoylamino)acetate

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

Procedure: To a solution of ethyl N-pivaloylglycinate (11.3 g) in 50 mL of methanol was added 69.2 mL of 1N sodium hydroxide, and the solution stirred for 2 hr. Solvents were evaporated in vacuo. Fresh methanol was added and reevaporated to give 12.45 g of off-white solid. Solvents were evaporated in vacuo Fresh methanol was added reevaporated

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

Procedure: To a solution of ethyl N-pivaloylglycinate (11.3 g) in 50 mL of methanol was added 69.2 mL of 1N sodium hydroxide, and the solution stirred for 2 hr. Solvents were evaporated in vacuo. Fresh methanol was added and reevaporated to give 12.45 g of off-white solid. Solvents were evaporated in vacuo Fresh methanol was added reevaporated

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

Procedure: To a solution of ethyl N-pivaloylglycinate (11.3 g) in 50 mL of methanol was added 69.2 mL of 1N sodium hydroxide, and the solution stirred for 2 hr. Solvents were evaporated in vacuo. Fresh methanol was added and reevaporated to give 12.45 g of off-white solid. Solvents were evaporated in vacuo Fresh methanol was added reevaporated

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

Procedure: 13.06 g of the above prepared (2,2-dimethyl-propionylamino)-acetic acid ethyl ester (69.75 mmol) was dissolved in 350 ml of abs. THF and cooled down to −78°. 146 ml of 1M lithium hexamethyldisilazide in THF (2.1 eq.) were slowly added via dropping funnel. After keeping the yellow suspension for 30 Min. at −78°, 6.491 ml of allyl bromide (1.1 eq.) was added and stirring continued for 15 Min. at the same temperature and for 40 Min. at 0°. Pouring of the homogeneous reaction mixture onto crashed ice/HCl, twofold extraction with AcOEt, twofold washing with water, drying over sodium sulfate, and evaporation of the solvents, followed by flash chromatography (SiO2, hexane/AcOEt=8/2) afforded 10.50 g of the title compound as colorless solid. In addition, 2.70 g of the di-allylated product (2-allyl-2-(2,2-dimethyl-propionylamino)-pent-4-enoic acid ethyl ester) was obtained from the less polar fractions. was dissolved in 350 ml of abs at 0° Pouring of the homogeneous reaction mixture ice/HCl, twofold extraction with AcOEt twofold washing with water drying over sodium sulfate, and evaporation of the solvents

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

Procedure: 13.06 g of the above prepared (2,2-dimethyl-propionylamino)-acetic acid ethyl ester (69.75 mmol) was dissolved in 350 ml of abs. THF and cooled down to −78°. 146 ml of 1M lithium hexamethyldisilazide in THF (2.1 eq.) were slowly added via dropping funnel. After keeping the yellow suspension for 30 Min. at −78°, 6.491 ml of allyl bromide (1.1 eq.) was added and stirring continued for 15 Min. at the same temperature and for 40 Min. at 0°. Pouring of the homogeneous reaction mixture onto crashed ice/HCl, twofold extraction with AcOEt, twofold washing with water, drying over sodium sulfate, and evaporation of the solvents, followed by flash chromatography (SiO2, hexane/AcOEt=8/2) afforded 10.50 g of the title compound as colorless solid. In addition, 2.70 g of the di-allylated product (2-allyl-2-(2,2-dimethyl-propionylamino)-pent-4-enoic acid ethyl ester) was obtained from the less polar fractions. was dissolved in 350 ml of abs at 0° Pouring of the homogeneous reaction mixture ice/HCl, twofold extraction with AcOEt twofold washing with water drying over sodium sulfate, and evaporation of the solvents

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

Procedure: 10.00 g of glycine ethyl ester hydrochloride (71.6 mmol) and 21.97 ml of NEt3 (2.2 eq.) were dissolved in 210 ml of CH2Cl2 and treated between 0° and 5° dropwise with 9.256 ml of benzoyl chloride (1.05 eq.), dissolved in 30 ml of CH2Cl2. The reaction mixture was allowed to reach ambient temperature (2.5 h) and then quenched by carefully pouring onto crashed ice/HCl/AcOEt. Separation of the layers, additional extraction of the aqueous phase with AcOEt, washing with Na2CO3 and brine, drying of the combined organic phase over sodium sulfate, and evaporation of the solvents left finally 13.06 g of pure title compound as colorless liquid. to reach ambient temperature (2.5 h) quenched by carefully pouring Separation of the layers, additional extraction of the aqueous phase with AcOEt washing with Na2CO3 and brine drying of the combined organic phase over sodium sulfate, and evaporation of the solvents left finally 13.06 g of pure title compound as colorless liquid

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

Procedure: 10.00 g of glycine ethyl ester hydrochloride (71.6 mmol) and 21.97 ml of NEt3 (2.2 eq.) were dissolved in 210 ml of CH2Cl2 and treated between 0° and 5° dropwise with 9.256 ml of benzoyl chloride (1.05 eq.), dissolved in 30 ml of CH2Cl2. The reaction mixture was allowed to reach ambient temperature (2.5 h) and then quenched by carefully pouring onto crashed ice/HCl/AcOEt. Separation of the layers, additional extraction of the aqueous phase with AcOEt, washing with Na2CO3 and brine, drying of the combined organic phase over sodium sulfate, and evaporation of the solvents left finally 13.06 g of pure title compound as colorless liquid. to reach ambient temperature (2.5 h) quenched by carefully pouring Separation of the layers, additional extraction of the aqueous phase with AcOEt washing with Na2CO3 and brine drying of the combined organic phase over sodium sulfate, and evaporation of the solvents left finally 13.06 g of pure title compound as colorless liquid

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

Procedure: 10.00 g of glycine ethyl ester hydrochloride (71.6 mmol) and 21.97 ml of NEt3 (2.2 eq.) were dissolved in 210 ml of CH2Cl2 and treated between 0° and 5° dropwise with 9.256 ml of benzoyl chloride (1.05 eq.), dissolved in 30 ml of CH2Cl2. The reaction mixture was allowed to reach ambient temperature (2.5 h) and then quenched by carefully pouring onto crashed ice/HCl/AcOEt. Separation of the layers, additional extraction of the aqueous phase with AcOEt, washing with Na2CO3 and brine, drying of the combined organic phase over sodium sulfate, and evaporation of the solvents left finally 13.06 g of pure title compound as colorless liquid. to reach ambient temperature (2.5 h) quenched by carefully pouring Separation of the layers, additional extraction of the aqueous phase with AcOEt washing with Na2CO3 and brine drying of the combined organic phase over sodium sulfate, and evaporation of the solvents left finally 13.06 g of pure title compound as colorless liquid

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

Procedure: To a vigorously-stirred slurry of phosphorus pentoxide (163.8 g., 1.15 mole) in chloroform (600 ml.) maintained under a nitrogen atmosphere is added slowly a solution of ethyl N-pivaloylglycinate (107.8 g., 0.576 mole) in chloroform (350 ml.). Upon completing the addition, the reaction mixture is stirred and heated at reflux under a nitrogen atmosphere for 14 hours. The cooled reaction mixture is treated with 20% sodium hydroxide (800 ml.), vigorously stirred for 1/2 hour and allowed to separate into two phases. After discarding the aqueous phase, the organic phase is washed with water and saturated brine, dried over sodium sulfate and filtered. Distillation of the filtrate provides 2-(1,1-dimethylethyl)-5-ethoxyoxazole as a pale yellow liquid (64 g., 66%), b.p. 58°-64° C./0.7 mm. the addition heated at reflux under a nitrogen atmosphere for 14 hours The cooled reaction mixture vigorously stirred for 1/2 hour to separate into two phases the organic phase is washed with water and saturated brine dried over sodium sulfate filtered Distillation of the filtrate

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

Procedure: To a solution of ethyl N-pivaloylglycinate (11.3 g) in 50 mL of methanol was added 69.2 mL of 1N sodium hydroxide, and the solution stirred for 2 hr. Solvents were evaporated in vacuo. Fresh methanol was added and reevaporated to give 12.45 g of off-white solid. Solvents were evaporated in vacuo Fresh methanol was added reevaporated