HCID 23520173, compound → HCID 59908504, compound

Participants

Reaction Steps

To a solution of mono-4-methyl 2-(R)-butylsuccinic acid, (prepared in three steps from hexanoylchloride and t-butyl bromoacetate as described below; 1 mmol) in DMF was added proline O-benzyl ester (1 mmol), DIEA (0.4 mL, 2.3 mmol), and a coupling reagent (e.g. EDCI, PyBOP, DIC, etc.; 1 mmol). The mixture was stirred overnight, then diluted with ethyl acetate and washed with aqueous HCl (1 N), water, saturated sodium bicarbonate, brine, and then dried (Na2SO4). The filtrate was concentrated and then purified on silica gel (Merck 60; ethyl acetate/hexane) to afford methyl-3-(R)-butyl-3-(2-(S)-benzyloxycarbonylpyrrolidin-1-ylcarbonyl)propionate. To this amide (0.1 mmol) in ethylacetate (10 mL) was added 10% Pd/C (100 mg) and the solution stirred under a hydrogen atmosphere for 8 h. The suspension was filtered through a Celite plug and then concentrated to afford methyl-3-(R)-butyl-3-(2-(S)-carboxypyrrolidin-1-ylcarbonyl)propionate E-2.

Provenance & Evidence