Synthesis
The general procedure for the synthesis of 3-oxa-9-azabicyclo[3.3.1]nonan-7-one hydrochloride from 9-Boc-7-oxa-9-azabicyclo[3.3.1]nonan-3-one was as follows: tert-butyl 7-oxo-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate A3 (160 mg, 0.66 mmol) was dissolved in Et2O ( 3 M solution, 3 mL) in HCl was added.The reaction mixture was stirred at room temperature for 2-3 hrs. After completion of the reaction, the mixture was concentrated and the crude product obtained was washed with ether to give the target product 3-oxa-9-azabicyclo[3.3.1]nonan-7-one hydrochloride as a yellow solid (120 mg, 100% yield).LCMS analysis results: retention time (RT) 0.24 min, m/z 142.1 [M + H]+.