反应详情

To a solution of isopropylamine (1.34 ml, 9.559 mmol) in THF (40 ml) at 0° C. was added n-butyllithium (3.65 ml of a 2.5M sol. In hexanes, 9.125 mmol). The resulting LDA solution was added via cannula to a solution of piperidine-1,4-dicarboxylic acid 1-tert-butyl ester 4 methyl ester (2.11 g, 8.690 mmol) in THF (40 ml) and HMPA (8 ml) at −78° C. and stirring continued for 1 hour. Benzyl bromide (1.19 ml, 9.994 mmol) in THF (5 ml) was then added and the solution warmed to room temperature over 2 hours. After stirring for 18 h, saturated aqueous ammonium chloride (200 ml) was added and the aqueous phase extracted with diethyl ether (2×100 ml). Organic phases were combined, dried over magnesium sulphate and concentrated to dryness. Purification by silica column chromatography (0.5% methanol in DCM) gave the ester as an oil (1.816 g, 63%). LC/MS: (LCT) Rt 7.67 [M+H]+333.

1. stirringAfter stirring for 18 h
2. extractionthe aqueous phase extracted with diethyl ether (2×100 ml)
3. dry with materialdried over magnesium sulphate
4. concentrationconcentrated to dryness
5. customPurification by silica column chromatography (0.5% methanol in DCM)