Acetaldehyde → 1-(3,3-Diphenylureido)ethylphosphonic acid

Participants

Reaction Steps

Freshly distilled acetaldehyde (0.22 mole) is added during 0.5 hr to a stirred solution of 0.1 mole each of 1,1-diphenylurea and triphenyl phosphite in 130g of benzene at 60° C. The solution is warmed at reflux (65°-70° with Dry Ice-cooled condenser) for 1.25 hr, giving a dark brown solution having a small 31P nmr peak at -126.2 ppm for unreacted phosphite and a large product peak at -18.4 ppm (~1:5 areas). The reaction mixture is stripped to 130°/3mm. The residue is diluted with 200 ml of acetonitrile and 10 g of H2O, and this solution is warmed at reflux for 3 hr. Solid that separates during warming is recrystallized from acetic acid-water to give a white solid; mp 186°-187° dec; P31 nmr -21.6 ppm; 1H nmr δ10.0 (s, 2, OH), 7.3 (m, 10, C 6 H5), 5.4 (d of d, 1, J = 9 and 5Hz, NH), 4.1 (m, 1, CH), 1.3 (d of d, 3, J = 16 and 7 Hz, CH3); acidity 2.00 equiv/mole, pK1 = 2.20, pK2 = 8.62.

Provenance & Evidence