ethyl (2R)-2-amino-2-phenylacetate

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

Procedure: Similarly to Example 18 but using ethyl DL-phenylglycinate (5.070 g., -- contains 0.05 mole methylene chloride i.e. 27.6 mmole) and (+)-tartaric acid (4.275 g., 28.5 mmole, 1.03 equiv.) in the filtrate from a previous resolution (Example 18, 50 ml. -- made up to volume with the first and then second washes), and giving ethyl D-phenylglycinate (+)-hemitartrate solvated with 1.0 mole methanol (8.049 g., 81%), [α]D23 - 46.7° (c 2.520, H2O).

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

Procedure: A solution of ethyl DL-phenylglycinate (5.051 g., contains 0.05 mole methylene chloride i.e. 27.5 mmole) and (+)-tartaric acid (4.264 g., 28.4 mmole, 1.03 equiv.) in methanol: acetone (1:1, 50 ml.) was stirred at 20° to 25°; crystallisation began immediately. After 231/2 hours the mixture was filtered and the product washed with solvent (2 × 12 ml.) and dried at 24°/2 mm. for 31/2 hours giving ethyl D-phenylglycinate (+)-hemitartrate solvated with 1.0 mole methanol (7.265g., 73%), [α]D24 - 47.4° (c 2.519, H2O). crystallisation After 231/2 hours the mixture was filtered the product washed with solvent (2 × 12 ml.) dried at 24°/2 mm

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

Procedure: A mixture of ethyl DL-phenylglycinate (5.021 g., 96% pure i.e. 27.0 mmole) and (+)-tartaric acid (2.027 g., 13.5 mmole, 0.5 equiv.) in ethanol (47 ml.) and benzaldehyde (2.75 ml., 2.88 g., 27.1 mmole, 1 equiv.) was stirred at 20°; crystallisation began within 5 minutes. After 10 days the mixture was filtered and the product washed with ethanol (2 × 7 ml.) and dried at 20°/4 mm. for 3 hours giving ethyl D-phenylglycinate (+)-hemitartrate solvated with 1.0 mole ethanol (3.922 g., 39% yield based on ester present or 78 % yield based on (+)-tartaric acid present), [α]D21 - 45.9° (c 2.506, H2O). crystallisation After 10 days the mixture was filtered the product washed with ethanol (2 × 7 ml.) dried at 20°/4 mm

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

Procedure: A solution of ethyl DL-phenylglycinate (5.00 g., 28 mmole) and (+)-tartaric acid (4.18 g., 28 mmole, 1 equiv.) in ethanol (50 ml.) was made at 58°. The solution was cooled, acetone (4.1 ml., 55.6 mmole, 2 equiv.) was added and the mixture was stirred at 20° to 25° for 165 hours. The solid was filtered off, washed with ethanol (2 × 10 ml.) and dried at 26°/2 mm. for 41/2 hours to give ethyl D-phenylglycinate (+)-hemitartrate as a monoethanol solvate (9.338 g., 89%), [α]D -46.5° (c 2.5 H2O). was made at 58° The solution was cooled The solid was filtered off washed with ethanol (2 × 10 ml.) dried at 26°/2 mm

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

Procedure: A solution of ethyl DL-phenylglycinate (6.26 g., 35 mmole) and (+)-tartaric acid (5.56 g., 1.05 equiv.) in dry methanol containing benzaldehyde (7% v/v benzaldehyde, 1 equiv; total volume 46 ml.) at 50° was cooled from 50° to 22° and stirred for 25 hours. The solid was filtered off and washed with methanol containing 7% benzaldehyde (15 ml.) then methanol (10 ml.) and dried at 22°/2 mm. for 3 hours to give ethyl D-phenylglycinate (+)-hemitartrate as a mono-methanol solvate (5.50 g., 43%), m.p. 131°-135° [α]D24 - 48° (c 2.68, H2O). was cooled from 50° to 22° The solid was filtered off washed with methanol containing 7% benzaldehyde (15 ml.) methanol (10 ml.) and dried at 22°/2 mm

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

Procedure: Solutions of ethyl DL-phenylglycinate (5.0 g., 27.95 mmole), (+)-tartaric acid (4.417 g., 29.45 mmole, 1.05 equiv.), and benzaldehyde (2.85 ml., 27.95 mmole, 1.0 equiv.) in ethanol (total volume 47 ml.) were mixed at 58°. The solution was cooled to 20° to 26° and stirred for 24 hours to give a white solid which was washed with ethanol (2 × 10 ml.), and dried at 29°/2 mm. for 6 hours to give ethyl D-phenylglycinate (+)-hemitartrate as a mono-ethanol solvate (7.95 g., 76%), [α]D20 -47° (c 2.5, H2O). The solution was cooled to 20° to 26° to give a white solid which was washed with ethanol (2 × 10 ml.) dried at 29°/2 mm