methyl (2R,4S)-4-hydroxypyrrolidine-2-carboxylate

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

Procedure: Add thionyl chloride (5.8 mL, 79.4 mmol) to an ice-cold suspension of 4-(S)-hydroxypyrrolidine-2-(R)-carboxylic acid (4.97 g, 31.9 mmol) in methanol (70 mL). Stir 10 min, then warm to room temperature and stir 3.5 h. Concentrate, add methanol and concentrate again to give the title compound as a white solid (7.18 g, 99%). stir 3.5 h Concentrate add methanol concentrate again

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

Procedure: Add thionyl chloride (5.8 mL, 79.4 mmol) to an ice-cold suspension of 4-(S)-hydroxypyrrolidine-2-(R)-carboxylic acid (4.97 g, 31.9 mmol) in methanol (70 mL). Stir 10 min, then warm to room temperature and stir 3.5 h. Concentrate, add methanol and concentrate again to give the title compound as a white solid (7.18 g, 99%). stir 3.5 h Concentrate add methanol concentrate again

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

Procedure: Thionyl chloride (0.83 ml, 11.4 mmol) is added dropwise into a suspension of H-D-Hyp-OH (1.0 g, 7.6 mmol) in methanol (25 ml) at 0° C. The mix is stirred at room temperature for 1 hr, then 65° C. for another 1 hr. Solvent is evaporated to dryness. Compound 18 is obtained as a white crystal and used for the next step. 65° C. for another 1 hr Solvent is evaporated to dryness

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

Procedure: Add thionyl chloride (5.8 mL, 79.4 mmol) to an ice-cold suspension of 4-(S)-hydroxypyrrolidine-2-(R)-carboxylic acid (4.97 g, 31.9 mmol) in methanol (70 mL). Stir 10 min, then warm to room temperature and stir 3.5 h. Concentrate, add methanol and concentrate again to give the title compound as a white solid (7.18 g, 99%). stir 3.5 h Concentrate add methanol concentrate again