Tetrahydrofuran → 3,3a-Dihydro-1H-oxazolo[3,4-a]quinoxaline-1,4(5H)-dione

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Reaction Steps

To 3-hydroxymethyl-1,2,3,4-tetrahydroquinoxalin-2-one (IV, EXAMPLE 286, 21.35 g), 1.00 g of carbonyldiimidazole, and 30 ml of THF are added 1.64. ml of triethylamine. The reaction is stirred at 20°-25° for 6 hr, then at 80° for 18 hr, at which time an additional 0.11 g carbonyldiimidazole are added. Heating is continued for another 6 hr, at which time the reaction mixture is cooled and the solvent is removed under reduced pressure. The residue is partitioned between methylene chloride and water, the organic layers are dried over sodium sulfate and concentrated. The residue is crystallized from methanol/dichloromethane to give the title compound, mp 230°-231°; MS (m/z) at 204; NMR (CDCl3) 4.60, 4.78, 6.93, 7.19, 7.82 and 8.48 δ.

Provenance & Evidence