Carbon Disulfide → Carbamodithioate

The intermediate 2-thioxo-3-(3-trifluoromethyl phenyl)-4-thiazolidinone was synthesized by dropwise addition of carbon disulfide (0.8 g, 10 mM) to a stirred solution of 3-trifluoromethylaniline (1.6 g, 10 mM) and triethylamine (1 g, 10 mM) in ethyl acetate (10 mL) over 30 minutes. An ice bath was used to prevent excessive heating during reaction. After stirring overnight, the thick yellow slurry was filtered and the precipitate was washed with 50 mL of ether and air dried to give 3 g (89% yield) of a pale yellow dithiocarbamate solid (melting point 92-95° C.). Na Br—14C-acetate (prepared from Br—14C-acetic acid (Amersham), 55 mCi/mmol, 64 mg, 0.46 mM in 0.6 mL of water, pH 8-9 using NaHCO3) was stirred and cooled to 5-10° C. and dithiocarbamate (0.3 g, 0.9 mM) was added over 10 minutes. Stirring was continued while the flask was allowed to warm to ambient temperature. After 2 hours, the solution was cooled to 10° C., acidified with concentrated HCl, and heated to 90-95° C. for 30 minutes. The resultant precipitate was filtered, washed with water and recrystallized from ethanol to give 103 mg of the desired product as shiny crystals (83% yield), m.p. 177-178° C.; specific activity (14C) 55 mCi/mmol; 1H NMR (300 MHz, CDCl3): δ 4.18 (s, 2H, CH2), 7.40 (d, 1H, phenyl, J=8.0 Hz), 7.48 (s, 1H, phenyl), 7.64 (t, 1H, phenyl, J=8.0 Hz), 7.72 (d, 1H, phenyl, J=7.6 Hz) ppm.

1. customAn ice bath was used
2. temperatureto prevent excessive heating during reaction
3. filtrationthe thick yellow slurry was filtered
4. washthe precipitate was washed with 50 mL of ether and air
5. customdried

ORD record

ord-905229b4d6dd410db3ad91360130e560

Source dataset

uspto-grants-2009_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07638543B2