Trimethyl phosphite → Dimethyl 3-[3-(trifluoromethyl)phenoxy]-2-semicarbazonopropylphosphonate

Participants

Reaction Conditions

Reaction Steps

A mixture of 1-chloro-3-[3-(trifluoromethyl)phenoxy]-2-propanone semicarbazone (36.5 g, 0.12 mol), P(OMe)3 (18.6 g, 0.15 mol) and toluene (100 mL) was refluxed for 3 h and cooled to 0° C. The precipitate was filtered off, washed on the filter with cold toluene and recrystallized from toluene to afford 26.8 g (59%) of dimethyl 3-[3-(trifluoromethyl)phenoxy]-2-semicarbazonopropylphosphonate as about 10:1 mixture of two isomers: mp 132–133° C. 1H NMR (CDCl3) (major isomer) δ: 9.40 (s, 1H), 7.37 (t, J=8.0 Hz, 1H), 7.19 (d, J=8.0 Hz, 1H), 7.15 (s, 1H), 7.07 (d, J=8.0 Hz, 1H), 5.80 (br.s, 2H), 4.68 (s, 2H), 3.76 (s, 3H), 3.73 (s, 3H), 3.11 (d, J=12 Hz, 2H).

Provenance & Evidence