Cyanogen Bromide → HCID 86626151, compound

Participants

Reaction Steps

To a 50 ml round-bottom flask containing a solution of lysergic acid methyl ester (1.0 g, 3.54 mmol) in anhydrous dichloromethane (50 ml) is slowly added cyanogen bromide (2.02 g, 19.11 mmol) and the resulting black-coloured reaction mixture is stirred at room temperature for 4 hours by which time TLC in 10% methanol/dichloromethane showed partial conversion of starting material to give two faster-running products. The reaction mixture is left stirring over the weekend and monitored by TLC showing no change. The reaction mixture is then stirred at 50° C. for 4 hours and is then extracted between tartaric acid and dichloromethane. The aqueous phase is re-extracted with dichloromethane (100 ml) and the combined organic phases washed with brine (200 ml), dried over MgSO4, filtered and concentrated in vacuo to give a dark brown (tar-coloured) oil. Purification is carried out by Normal Phase Flash column chromatography (Biotage Flash 40, 90 g cartridge) using 40% ethyl acetate/hexane to achieve separation of the fast-running product which is isolated as a pale yellow solid. The product is crystallized from tert. Butyl methylether and slowly evaporated. The resulting crystallized material is filtered at the pump to give pale yellow crystals.

Provenance & Evidence