4-(3-methoxypropyl)-3-oxo-3,4-dihydro-2H-benzo[1,4]oxazine-6-carbaldehyde → 6-(1-Hydroxyethyl)-4-(3-methoxypropyl)-4H-benzo[1,4]oxazin-3-one

Participants

Reaction Conditions

Reaction Steps

The solution of 1.0 g of 4-(3-methoxypropyl)-3-oxo-3,4-dihydro-2H-benzo[1,4]oxazine-6-carbaldehyde and 30 ml of tetrahydrofuran is cooled to 0° C. and admixed dropwise with 1.4 ml of methylmagnesium bromide (35% in THF). The reaction mixture is stirred at 0° C. for a further 15 minutes, subsequently quenched with saturated ammonium chloride solution (50 ml) and extracted with tert-butyl methyl ether (2×50 ml). The organic phases are washed successively with ice-water (50 ml) and brine (50 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=0.16 (3:1 EtOAc-heptane); Rt=2.96.

Provenance & Evidence