Triphenylphosphine Oxide → HCID 56933439, compound

Participants

Reaction Steps

To a stirred yellow suspension of (E)-2,2,7-trifluoro-4-(prop-2-ynyl)-6-(2-(3,3,3-trifluoro-2-oxopropylidene)hydrazinyl)-2H-benzo[b][1,4]oxazin-3-one (1399 mg, 3.69 mmol) in dry toluene (20 ml) was added (carbethoxyethylidene)triphenylphosphorane (1738 mg, 4.80 mmol), resulting in a clear orange/red solution. The reaction was continued overnight at reflux under Dean-Stark conditions, while conducting aezotropic dehydration. Thereupon the reaction mixture was concentrated in vacuo to yield 2.99 g of crude product containing ca. 50% triphenylphosphine oxide. The crude product was chromatographed over silica (9:1→1:1 heptane/ethyl acetate) to yield 1.08 g of product (ca. 89% purity). Recrystallisation from diisopropyl ether/heptane gave the title compound as a white powder (purity>99%).

Provenance & Evidence