Imidazole → Triphenylphosphine Oxide

Participants

Reaction Steps

A solution of 0.8 ml of bromine in 15 ml of toluene is added, dropwise, to a solution of 4.0 gr. of 2-(RS)-(2-hydroxyethyl)-2,3-dihydro-5-benzyloxy-4,6,7-trimethylbenzofurane, 5.1 g of triphenylphosphine and 1.3 gr of imidazol in 70 ml of toluene. The mixture is stirred at room temperature for 15 minutes, after which the imidazol*HBr is filtered out and the filtrate is evaporated. The residue is treated with ethylic ether to obtain a precipitate of triphenylphosphine oxide, which is filtered out. After the residue has been evaporated, the obtained 7.7 g of raw material is purified by means of the column chromatography (SiO2), which produces 4.0 g of a yellow solid. m.p. 66°-68° C.; IR(KBr): 1549 (νC--C), 1075 cm-1 (νC--O--C); 1H-NMR (CDCl3): δ7.4-7.1 (5H,m), 5.0-4.5 (1H,m), 4.6 (2H,s), 3.5 (2H,t), 3.3-2.6 (2H,m), 2.3-2.1 (2H,m), 2.05 (9H,s).

Provenance & Evidence