Hydrochloric Acid → 1,4'-Bipiperidin-4-ol

Participants

Reaction Steps

4-Oxo-piperidine-1-carboxylic acid tert-butyl ester (20 g) and 4-hydroxypiperidine (6.7 g) were stirred together in dichloroethane (200 ml) with acetic acid (4 ml) at RT for 30 minutes. Sodium triacetoxyborohydride (23 g) was then added and the mixture stirred at RT overnight. The mixture was evaporated to dryness and the residue taken into water, extracted with diethyl ether (3×200 ml), the aqueous was basified to pH 9-10 and extracted with dichloromethane (3×200 ml). The dichloromethane extracts were combined, dried (MgSO4) and evaporated to leave an oil (19 g; same compound as Example 9 step 1). The oil was dissolved in methanol (300 ml) and treated with concentrated hydrochloric acid (5 ml). The mixture was stirred overnight and then evaporated to dryness to leave the title compound as the hydrochloride salt (15 g).

Provenance & Evidence