Trifluoroacetic acid → 4-{[(2S)-2-Hydroxy-3-(9-oxa-3,7-diazabicyclo[3.3.1]non-3-yl)propyl]-oxy}benzonitrile

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Reaction Steps

A 3 L, three-necked flask equipped with a magnetic stirrer, a thermometer and an addition funnel was charged with unpurified tert-butyl 7-[(2S)-3-(4-cyanophenoxy)-2-hydroxypropyl]-9-oxa-3,7-diazabicyclo[3.3.1]nonane-3-carboxylate (100 g, from step (ii) above) and dichloromethane (1.15 L). Trifluoroacetic acid (0.352 L) was added slowly at room temperature and the resulting solution was stirred for three hours, at which point TLC analysis showed complete reaction. The contents were transferred to a single-necked flask and concentrated under vacuum. The residue was dissolved in dichloromethane (1.2 L) and washed with saturated sodium bicarbonate. The aqueous layer was separated and extracted with dichloromethane (2×0.2 L). The combined organic layers were washed with brine (0.25 L), dried over magnesium sulfate and concentrated under vacuum to afford 73 g (>100% yield) of sub-title compound as an off-white solid. The unpurified material was used in the next step.

Provenance & Evidence