Piperidine → [1-(Acetylaminomethyl)-2,3-dioxo-3-piperidin-1-yl-propyl]carbamic acid benzyl ester

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Reaction Steps

A solution of [1-(acetylaminomethyl)-3-cyano-2-oxo-3-(triphenyl-λ5-phosphanylidene) propyl]carbamic acid benzyl ester (prepared as described in Example 10) (572 mg, 1.01 mmol, 1 equiv) in CH2Cl2 (11 mL) at −78° C. was treated with ozone gas for 2 h. The chilled solution was then purged with Ar for 10 min until the color had changed from green to yellow. Piperidine (0.110 mL, 1.12 mmol, 1.1 equiv) was added dropwise over 1 min, and stirring continued at −78° C. for 15 min. The volatiles were removed under reduced pressure, and the residue purified by flash column chromatography (5% CH3OH in CH2Cl2) to give [1-(acetylaminomethyl)-2,3-dioxo-3-piperidin-1-yl-propyl]carbamic acid benzyl ester (120.7 mg, 32% yield) as a colorless foam. Rf=0.30 (EtOAc). IR (cm−1) 3304, 1720, 1639, 1537. 1H NMR (CDCl3) δ1.59 (br s, 7H), 1.97 (s, 3H), 3.22-3.91 (m, 7H), 4.54-4.58 (m, 1H), 5.09 (s, 2H), 6.28 (br s, 1H), 6.67 (br s, 1H), 7.34 (s, 5H).

Provenance & Evidence