D-Proline → HCID 11790498, compound

Participants

Reaction Steps

(R)-proline (20 g, 0.174 mol) was placed in a 500 mL round-bottom flask. To this was added 100 mL THF and ethyl trifluoroacetate (50 g, 0.34 mol). The solution was purged with argon and 1,1,3,3-tetramethylguanidine (30 g, 0.261 mol) was added dropwise. The solution was allowed to stir until all the (R)-proline had dissolved (approximately 35 minutes). The solvent was removed in vacuo and the residue dissolved in CH2Cl2 (200 mL). The solution was washed with 6N HCl (aqueous, 2×100 mL). The organic layer was separated and dried with Na2SO4, filtered and the solvent removed in vacuo to give as an oil which crystallized upon standing; yield 29 g (79%), m.p. 48°-51° C.

Provenance & Evidence