Methanol → 4-Hydroxyamino-1-methoxy-piperidine-4-carboxylic acid methyl ester

Participants

Reaction Steps

To a suspension of 4-hydroxyamino-1-methoxy-piperidine-4-carboxylic acid (1.0 g, 5.26 mmol) in methanol (25 ml) at 0-10° C. was added thionyl chloride (1.14 ml, 1.88 g, 15.77 mmol) and the reaction mixture was heated at reflux for 48 hours. After cooling, the mixture was concentrated, the residue diluted with ice water (20 ml) and neutralised with aqueous sodium bicarbonate. The aqueous phase was extracted with diethyl ether (3×25 ml), the combined organic layers washed with aqueous sodium bicarbonate and brine, dried over sodium sulfate and concentrated. Yield: 0.53 g of 4-hydroxyamino-1-methoxy-piperidine-4-carboxylic acid methyl ester (title compound P4ii.2) as a viscous, yellowish oil. This material was identical to the compound described above under preparation ‘EXAMPLE 11, Step 3’.

Provenance & Evidence