Toluene → 1-(1,3-Dimethylureido)-3-(methylthio)propylphosphonic acid

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Reaction Steps

When a mixture of 0.5 mole each of 1,3-dimethylurea, triphenyl phosphite, and 3-methylthiopropionaldehyde in 100g of toluene is warmed to 75°, a reaction is initiated and the temperature increases rapidly to 120°. After further warming at 105° for 1 hr, the resulting yellow solution has a 31P nmr signal only at -28.2 ppm. After the solvent and most of the byproduct phenol are removed by stripping to 110°/1mm, one-third of the residue is dissolved in 75ml of acetonitrile and 10g of water, and this solution is refluxed for 3 hr. The reaction mixture is allowed to evaporate to dryness, and the residue is extracted with ether and then with hot acetonitrile and recrystallized twice from acetic acid to give a white solid: mp 164.5°-167°; 31P nmr (DMSO-d6) -21.4 ppm; 1H nmr δ9.6 (broad, 2, OH), 4.5 (m, 1, PCH), 2.8 (s, NCH3), 2.6 (s, NCH3), 2.0 (s, SCH3), 1.9-2.6 (m, CH2CH2S).

Provenance & Evidence