4-benzylidene-2-methyl-1,3-oxazol-5-one

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

Procedure: The invention relates to a process for the preparation of N-acetylphenylalanine by opening the ring of 2-methyl-4-benzylidene-1,3-oxazolin-5-one with water to give 2-acetaminocinnamic acid and subsequent catalytic hydrogenation of the latter.

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

Procedure: In the process for the preparation of N-acetylphenylalanine by opening the ring of 2-methyl-4-benzylidene-1,3-oxazolin-5-one with water to give 2-acetaminocinnamic acid and subsequently catalytically hydrogenating the latter, both reaction stages are carried out in a mixture of an aliphatic C3 -ketone to C10 -ketone or a water-miscible ether and water as the solvent, and the hydrogenation of the 2-acetaminocinnamic acid is carried out at temperatures of 10° to 50° C. and pressures of 1 to 15 bar in the presence of a supported palladium catalyst.

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

Procedure: The invention relates to a process for the preparation of N-acetylphenylalanine by opening the ring of 2-methyl-4-benzylidene-1,3-oxazolin-5-one with water to give 2-acetaminocinnamic acid and subsequent catalytic hydrogenation of the latter.

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

Procedure: In the process for the preparation of N-acetylphenylalanine by opening the ring of 2-methyl-4-benzylidene-1,3-oxazolin-5-one with water to give 2-acetaminocinnamic acid and subsequently catalytically hydrogenating the latter, both reaction stages are carried out in a mixture of an aliphatic C3 -ketone to C10 -ketone or a water-miscible ether and water as the solvent, and the hydrogenation of the 2-acetaminocinnamic acid is carried out at temperatures of 10° to 50° C. and pressures of 1 to 15 bar in the presence of a supported palladium catalyst.

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

Procedure: In the process for the preparation of N-acetylphenylalanine by opening the ring of 2-methyl-4-benzylidene-1,3-oxazolin-5-one with water to give 2-acetaminocinnamic acid and subsequently catalytically hydrogenating the latter, both reaction stages are carried out in a mixture of an aliphatic C3 -ketone to C10 -ketone or a water-miscible ether and water as the solvent, and the hydrogenation of the 2-acetaminocinnamic acid is carried out at temperatures of 10° to 50° C. and pressures of 1 to 15 bar in the presence of a supported palladium catalyst.

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

Procedure: In 100-ml tightly-sealed glass vessel were charged 9.36 g of 2-methyl-4-benzylidene-5-oxazolone and 40 ml of water. 4.15 g of potasium carbonate was then added thereto and the resulting mixture was stirred at 40°-45° C. for two hours. Concentrated hydrochloric acid was added to the resulting solution to adjust its pH at 6.8 and 0.2 g of 5%-palladium-carbon was added thereto. The gas phase in the vessel was purged with nitrogen and then with hydrogen, and thereafter the reaction mixture in the vessel was subjected to catalytic reduction at 40°-45° C. under atmospheric pressure. The reaction time during which hydrogen absorption was completed was 100 minutes. It was observed that one mole of hydrogen was absorbed to one mole of 2-methyl-4-benzylidene-5-oxazolone during this period. After the gas phase in the vessel was purged with nitrogen upon completion of the reaction, the catalyst was filtered and washed with a small amount of water. The filtrate and the washings were combined, to which concentrated hydrochloric acid was added at a temperature lower than 30° C. to adjust pH of the resulting mixture at 1. The mixture was cooled to 0°-5° C. The crystal was filtered, washed with a cold water and dried to obtain 9.81 g of N-acetylphenylalanine having a melting point 150°-151° C. as a white crystal. Its yield was 94.7%. In 100-ml tightly-sealed glass vessel was added The gas phase in the vessel was purged with nitrogen was subjected to catalytic reduction at 40°-45° C. under atmospheric pressure The reaction time during which hydrogen absorption was completed was 100 minutes After the gas phase in the vessel was purged with nitrogen upon completion of the reaction the catalyst was filtered washed with a small amount of water was added at a temperature lower than 30° C. The mixture was cooled to 0°-5° C The crystal was filtered washed with a cold water dried

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

Procedure: In a 100-ml tightly-sealed glass vessel were charged 9.36 g of 2-methyl-4-benzylidene-5-oxazolone and 30 ml of water. Then, 5.3 g of 45% sodium hydroxide solution was added thereto and the resulting mixture was stirred at 40°-45° C. for two hours. The 2-methyl-4-benzylidene-5-oxazolone was hydrolyzed to form an aqueous homogeneous solution of sodium α-acetylaminocinnamate. The solution had a pH in excess of 12. 0.2 g of 5%-palladium-carbon was then added to the solution. After the gas phase in the vessel was purged with nitrogen and then with hydrogen, the reaction mixture in the vessel was subjected to catalytic reduction at 40°-45° C. under atmospheric pressure. The time required for the reduction was approximately four hours. After completion of the reduction, the reaction mixture was treated in the same manner as in Example 1 to obtain 9.91 g of N-acetylphenylalanine as a white crystal. Its melting point was 149.5°-150.5° C. In a 100-ml tightly-sealed glass vessel

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

Procedure: In a 100-ml tightly-sealed glass vessel were charged 9.36 g of 2-methyl-4-benzylidene-5-oxazolone and 30 ml of water. Thereafter, 5.3 g of 45% sodium hydroxide solution was added thereto and the resulting mixture was stirred at 40°-45° C. for 2 hours. The 2-methyl-4-benzylidene-5-oxazolone was hydrolyzed to form an aqueous homogeneous solution of sodium α-acetylaminocinnamate. Then, concentrated hydrochloric acid was added to the solution to adjust its pH at 7.2, and subsequently 0.2 g of 5%-palladium-carbon was added thereto. The gas phase in the vessel was purged with nitrogen and then with hydrogen and thereafter the content in the vessel was subjected to catalytic reduction at 40°-45° C. under atmospheric pressure. The reaction time was approximately 90 minutes until hydrogen absorption was completed. During this time period, it was observed that one mole of hydrogen was absorbed to one mole of 2-methyl-4-benzylidene-5-oxazolone. In a 100-ml tightly-sealed glass vessel

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

Procedure: In 100-ml tightly-sealed glass vessel were charged 9.36 g of 2-methyl-4-benzylidene-5-oxazolone and 40 ml of water. 4.15 g of potasium carbonate was then added thereto and the resulting mixture was stirred at 40°-45° C. for two hours. Concentrated hydrochloric acid was added to the resulting solution to adjust its pH at 6.8 and 0.2 g of 5%-palladium-carbon was added thereto. The gas phase in the vessel was purged with nitrogen and then with hydrogen, and thereafter the reaction mixture in the vessel was subjected to catalytic reduction at 40°-45° C. under atmospheric pressure. The reaction time during which hydrogen absorption was completed was 100 minutes. It was observed that one mole of hydrogen was absorbed to one mole of 2-methyl-4-benzylidene-5-oxazolone during this period. After the gas phase in the vessel was purged with nitrogen upon completion of the reaction, the catalyst was filtered and washed with a small amount of water. The filtrate and the washings were combined, to which concentrated hydrochloric acid was added at a temperature lower than 30° C. to adjust pH of the resulting mixture at 1. The mixture was cooled to 0°-5° C. The crystal was filtered, washed with a cold water and dried to obtain 9.81 g of N-acetylphenylalanine having a melting point 150°-151° C. as a white crystal. Its yield was 94.7%. In 100-ml tightly-sealed glass vessel was added The gas phase in the vessel was purged with nitrogen was subjected to catalytic reduction at 40°-45° C. under atmospheric pressure The reaction time during which hydrogen absorption was completed was 100 minutes After the gas phase in the vessel was purged with nitrogen upon completion of the reaction the catalyst was filtered washed with a small amount of water was added at a temperature lower than 30° C. The mixture was cooled to 0°-5° C The crystal was filtered washed with a cold water dried

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

Procedure: In a 100-ml tightly-sealed glass vessel were charged 9.36 g of 2-methyl-4-benzylidene-5-oxazolone and 30 ml of water. Then, 5.3 g of 45% sodium hydroxide solution was added thereto and the resulting mixture was stirred at 40°-45° C. for two hours. The 2-methyl-4-benzylidene-5-oxazolone was hydrolyzed to form an aqueous homogeneous solution of sodium α-acetylaminocinnamate. The solution had a pH in excess of 12. 0.2 g of 5%-palladium-carbon was then added to the solution. After the gas phase in the vessel was purged with nitrogen and then with hydrogen, the reaction mixture in the vessel was subjected to catalytic reduction at 40°-45° C. under atmospheric pressure. The time required for the reduction was approximately four hours. After completion of the reduction, the reaction mixture was treated in the same manner as in Example 1 to obtain 9.91 g of N-acetylphenylalanine as a white crystal. Its melting point was 149.5°-150.5° C. In a 100-ml tightly-sealed glass vessel

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

Procedure: In a 100-ml tightly-sealed glass vessel were charged 9.36 g of 2-methyl-4-benzylidene-5-oxazolone and 30 ml of water. Thereafter, 5.3 g of 45% sodium hydroxide solution was added thereto and the resulting mixture was stirred at 40°-45° C. for 2 hours. The 2-methyl-4-benzylidene-5-oxazolone was hydrolyzed to form an aqueous homogeneous solution of sodium α-acetylaminocinnamate. Then, concentrated hydrochloric acid was added to the solution to adjust its pH at 7.2, and subsequently 0.2 g of 5%-palladium-carbon was added thereto. The gas phase in the vessel was purged with nitrogen and then with hydrogen and thereafter the content in the vessel was subjected to catalytic reduction at 40°-45° C. under atmospheric pressure. The reaction time was approximately 90 minutes until hydrogen absorption was completed. During this time period, it was observed that one mole of hydrogen was absorbed to one mole of 2-methyl-4-benzylidene-5-oxazolone. In a 100-ml tightly-sealed glass vessel

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

Procedure: The invention relates to a process for the preparation of N-acetylphenylalanine by opening the ring of 2-methyl-4-benzylidene-1,3-oxazolin-5-one with water to give 2-acetaminocinnamic acid and subsequent catalytic hydrogenation of the latter.