Hydrochloric Acid → 6-(Hydroxymethyl)-2H-1,4-benzoxazin-3(4H)-one

Participants

Reaction Conditions

Reaction Steps

A mixture of 6.9 g of methyl 3-oxo-3,4-dihydro-2H-benzo[1,4]oxazine-6-carboxylate in 230 ml of tetrahydrofuran is cooled to −40° C. 88.9 ml of diisobutylaluminium hydride (1.5M in toluene) are added dropwise at −40° C. over the course of 30 minutes. The reaction mixture is stirred at −40° C. to −20° C. for 1.5 hours and then cautiously poured into 150 ml of 2N HCl (cold). The organic phase is separated off, and the aqueous phase is extracted with tetrahydrofuran (5×100 ml). The organic phases are washed with brine (1×100 ml), filtered through cotton wool and evaporated. The title compound is obtained as beige crystals from the residue by crystallization (from ethanol). Rf=0.16 (EtOAc/heptane 2.1); Rt=2.23; m.p.: 186-187° C.

Provenance & Evidence