Cyclopentanecarbaldehyde → ethyl (2E)-3-(6-{(tert-butoxycarbonyl)[(3R)-1-(cyclopentylmethyl)-3-pyrrolidinyl]amino}-3-pyridinyl)acrylate

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Reaction Steps

To a solution of ethyl (2E)-3-(6-{(tert-butoxycarbonyl)[(3R)-3-pyrrolidinyl]amino}-3-pyridinyl)acrylate dihydrochloride (220 mg, 0.51 mmol) in 1,2-dichloroethane (4 mL) were added diisopropylethylamine (131 mg, 1.01 mmol) and cyclopentanecarboxaldehyde (52 mg, 0.53 mmol), and the mixture was stirred at ambient temperature for 5 min. To the mixture was added sodium triacetoxyborohydride (215 mg, 1.01 mmol) and stirred for 2 hrs, and resulting mixture was poured into saturated sodium bicarbonate solution, and extracted with ethyl acetate. The organic layer was washed with water, and brine, and dried over magnesium sulfate. The solvent was removed in vacuo and the residue was purified by preparative thin layer chromatography (chloroform-MeOH=10-1) to give ethyl (2E)-3-(6-{(tert-butoxycarbonyl)[(3R)-1-(cyclopentylmethyl)-3-pyrrolidinyl]amino}-3-pyridinyl)acrylate (225 mg, 100%) as an amorphous powder.

Provenance & Evidence