Triphenylphosphine → Triphenylphosphane dibromide

Participants

Reaction Steps

To a solution of 9.13 g (0.035 mole) of triphenylphosphine in 70 ml of dimethylformamide at 5°-10° C. was slowly added 1.93 ml (0.035 mole) of bromine to form triphenylphosphine dibromide. The yellow-orange mixture was then treated with 1.91 g (0.01 mole) of 2,4-diamino-6-hydroxymethylpyrido[2,3-d]pyrimidine at 10° C. The mixture was stirred for 45 minutes at ambient temperature. The red solution was cooled to 10° C., treated with 1 ml of ethanol (dropwise) and stirred for an hour at ambient temperature. The solution was concentrated to a volume of 10 ml in vacuo and washed thrice with 90-ml portions of warm (40° C.) benzene. The residual liquid was treated with 30 ml of hot acetic acid. The hot solution was filtered and the filtrate chilled to afford 2.44 g of crystalline precipitate; UV λ pH 1 248 nm (ε 20, 200), 320 (8,780), 333 (7,030); λ pH 13 270 (11,050), 342 (6,300 ). Calc'd for C8H8N5Br.HBr: C, 28.7; H, 2.7; N, 20.9; Br, 47.7. Found: C, 28.9; H, 2.85; N, 21.1; Br, 47.4.

Provenance & Evidence