Sodium hydride → 6-Hydroxymethyl-4-(4-triisopropylsilanyloxybutyl)-4H-benzo[1,4]oxazin-3-one

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Reaction Steps

The stirred solution of 3.70 g of 6-hydroxymethyl-4H-benzo[1,4]oxazin-3-one (Example 2d) and 95 ml of N,N-dimethylformamide is cooled to 0° C., admixed with 0.808 g of sodium hydride (60% dispersion) and stirred over 1 hour. After 7.57 g of (4-bromobutoxy)triisopropylsilane have been added, the mixture is stirred at 0° C. over a further 18 hours and the resulting reaction mixture is poured onto aqueous 1M sodium hydrogencarbonate solution (200 ml). The mixture is extracted with tert-butyl methyl ether (2×200 ml). The organic phases are washed successively with water (3×200 ml) and brine (200 ml), dried over sodium sulphate, filtered and concentrated by evaporation. The title compound is obtained as a slightly yellowish oil from the residue by means of flash chromatography (SiO2 60F). Rf=0.43 (1:1 EtOAc-heptane); Rt=5.86.

Provenance & Evidence