HCID 21568317, compound → HCID 21568320, compound

Participants

Reaction Steps

A solution of the crude 4-bromo-1-oxo-1-vinyl-1,2,3,4-tetrahydrophosphinoline (5.5g) in anhydrous dimethyl formamide (30 ml) was heated under nitrogen at 110° for 45 min, after which time an n.m.r. spectrum indicated that dehydrobromination was complete. The excess of dimethyl formamide was evaporated in vacuum, and the brown semi-solid residue was dissolved in chloroform. This solution was washed with water, dried, and evaporated. Distillation of the residue through a short Vigreux column gave a colourless liquid b.p. 134°-138°/0.005 (3.6g, 90%). Preparative t.l.c. on silica gel plates developed with chloroform-methanol 30-1, followed by bulb-to-bulb distillation gave the "pure" compound. However, complete removal of water was not achieved, nor was a unique hydrate obtained, and the compound failed to give satisfactory microanalytical figures. Infrared spectrum νmax : 3030, 2930, 2860, 1630, 1590, 1475, 1440, 1390, 1275, 1180, 1140, 990, 865, 785, 720 cm-1. N.m.r. spectrum (CDCl3): 7.0-8.0, m. 4H (aromatic); 5.6-6.8, m, 5H (olefinic); 2.6-3.1, m, 2H (methylene). Mass spectrum: m/e 190 (57%), 141 (41), 128 (38), 116 (66), 115 (100), 89 (27), 65 (34), 51 (50). Ultraviolet spectrum λmax (ethanol): 222 (19600) 262 (4200), 298 (2300).

Provenance & Evidence