(2S,3S)-3-methylpyrrolidine-2-carboxylic acid

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

Procedure: The title compound was prepared from (3S)-3-methyl-L-proline, using the methods used to prepare ethyl(3S)-3-hydroxy-L-prolinate hydrochloride. 1H NMR (400 MHz, DMSO-D6) δ ppm 1.1 (d, J=6.8 Hz, 3 H) 1.2 (t, J=6.8 Hz, 3 H) 1.6 (m, 1 H) 2.1 (m, 1 H) 2.3 (m, 1 H) 3.2 (m, 2 H) 3.8 (m, 1 H) 4.2 (m, 2 H) 4.7 (m, 1 H) 9.0 (s, 1 H) 10.4 (s, 1 H).

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

Procedure: The title compound was prepared from (3S)-3-methyl-L-proline, using the methods used to prepare ethyl(3S)-3-hydroxy-L-prolinate hydrochloride. 1H NMR (400 MHz, DMSO-D6) δ ppm 1.1 (d, J=6.8 Hz, 3 H) 1.2 (t, J=6.8 Hz, 3 H) 1.6 (m, 1 H) 2.1 (m, 1 H) 2.3 (m, 1 H) 3.2 (m, 2 H) 3.8 (m, 1 H) 4.2 (m, 2 H) 4.7 (m, 1 H) 9.0 (s, 1 H) 10.4 (s, 1 H).

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

Procedure: The title compound was prepared from (3S)-3-methyl-L-proline, using the methods used to prepare ethyl(3S)-3-hydroxy-L-prolinate hydrochloride. 1H NMR (400 MHz, DMSO-D6) δ ppm 1.1 (d, J=6.8 Hz, 3H) 1.2 (t, J=6.8 Hz, 3H), 1.6 (m, 1H), 2.1 (m, 1H), 2.3 (m, 1H), 3.2 (m, 2H), 3.8 (m, 1H), 4.2 (m, 2H), 4.7 (m, 1H), 9.0(s, 1H), 10.4 (s, 1H).

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

Procedure: Triethylamine (3.5 ml) and t-butyl-2,4,5-trichlorophenyl carbonate (3.5 g) were added to a solution of trans-3-methyl-L-proline (1.25 g) in t-butanol (12 ml) and water (8 ml). The mixture was heated to 60° for 2 hours, evaporated, the residue dissolved in 1 N sodium bicarbonate solution (50 ml) and the solution washed with ether. Excess solid citric acid was added, the product extracted into ethyl acetate, the combined extracts dried (Na2SO4) and evaporated giving a crude crystalline product (1.6 g). Recrystallisation from ethyl acetate/light petroleum (40°-60°) gave the desired product (1.33 g), m.p. 146°-150° [α]D20 - 60.1° (c, 1.0, chloroform) The mixture was heated to 60° for 2 hours evaporated the residue dissolved in 1 N sodium bicarbonate solution (50 ml) the solution washed with ether Excess solid citric acid was added the product extracted into ethyl acetate the combined extracts dried (Na2SO4) evaporated