Sodium hydride → (4aR*,8aR*)-2-oxo-octahydro-pyrido[3,4-b][1,4]oxazine-6-carboxylic acid tert-butyl ester

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Reaction Steps

To a stirred mixture of 249B (410 mg, 14.0 mmol) in 10 mL of dry THF under N2 at room temperature was added 60% NaH (84.0 mg, 2.10 mmol). This mixture was stirred at room temperature for 45 min and quenched with 3 mL of saturated NH4Cl solution. The mixture was concentrated in vacuo and diluted with 40 mL of saturated NaHCO3 solution. The aqueous solution was extracted with EtOAc (3×60 mL). The combined EtOAc extracts were washed with brine (1×30 mL). The EtOAc layer was dried (MgSO4), filtered and concentrated in vacuo to give 344 mg (yield: 96%) of 249C. It had an analytical HPLC retention time=2.01 min. (Chromolith SpeedROD 4.6×50 mm, 10-90% aqueous methanol over 4 minutes containing 0.2% phosphoric acid, 4 ml/min, monitoring at 220 nm) and a LC/MS M+=257.

Provenance & Evidence