Phosgene → HCID 11793365, compound

Participants

Reaction Steps

To 3-(5-cyclopropyl-1,2,4-oxadiazol-3-yl)-6-fluoro-4,5-dihydroimidazo[1,5-a]quinoxaline (XXXIII, EXAMPLE 103, 0.520 g) in THF (15 ml) is added diisopropylethylamine (0.305 ml) followed by phosgene (1.2M in toluene, 2.19 ml). After stirring for 3 hr, dimethylamine hydrochloride (0.285 g) is added, followed by diisopropylethylamine (0.91 ml). The reaction is stirred for 3 hr, after which several ml of aqueous sodium bicarbonate is added. The reaction is concentrated under reduced pressure and the residue partitioned between dichloromethane, aqueous sodium bicarbonate and saline. The phases are separated, the organic phase is dried over sodium sulfate and concentrated. The solid is chromatographed on silica gel (150 ml) eluting with methanol/dichloromethane (2/98). The appropriate fractions are pooled and concentrated to give a solid, which is recrystallized from dichloromethane and hexane to give the title compound, mp 194°-195°; MS m/z at 368; IR (mineral oil) 1657, 1502, 1391, 786 and 1224 cm-1 ; NMR (CDCl3) 1.25, 1.36, 2.25, 2.94, 5.05, 7.08, 7.21, 7.37, 8.11 δ.

Provenance & Evidence