8-(Pyridin-4-yl)-1,4-dioxa-8-azaspiro[4.5]decane → 1-(Pyridin-4-yl)piperidin-4-one

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Reaction Steps

A solution of 8-(4-pyridyl)-1,4-dioxa-8-azaspiro[4,5]decane (10 g) in 2N sulphuric acid (140 ml) and tetrahydrofuran (70 ml) was stirred for 72 hr. The reaction was quenched with water (700 ml) and extracted with dichloromethane (400 ml). The organic extracts were dried (MgSO4) and evaporated to give a yellow solid which was purified by flash chromatography on silica, eluting with methanol/dichloromethane (10:90 v/v) to give 1-(4-pyridyl)-4-oxopiperidine as a solid (3.97 g); m.p. 101°-104° C.; NMR (d6-DMSO) δ 2.45 (4H, t), 3.75 (4H, t), 6.85 (2H, m), 8.20 (2H, m); m/e 177 (M+H)+.

Provenance & Evidence