Hydrochloric Acid → 4-Isothiocyanatobenzoic acid

Carbon disulfide (0.67 mL, 11 mmol) was added to a mixture comprising 4-aminobenzoic acid (0.50 g, 3.6 mmol), N,N-dimethylformamide (6.3 mL) and triethylamine (1.3 mL, 9.3 mmol), followed by stirring at room temperature for 4 hours. To the obtained reaction mixture, bromine (0.20 mL, 3.8 mmol) was dropwise added over a period of 20 minutes at 0° C., followed by stirring at 0° C. for further two hours. Thereafter, 1M hydrochloric acid (3.6 mL), sodium sulfite (0.092 g, 0.72 mmol) and water (5.0 mL) were added and mixed. Then, ethyl acetate (15 mL) was added, and the solid was collected by filtration and washed with ethyl acetate (1.0 mL). Obtained crystals were dried under reduced pressure at 50° C. to obtain 4-isothiocyanatobenzoic acid as a slightly yellow solid (0.16 g, yield: 25%, HPLC purity: 94%, HPLC retention time: 3.7 min).

1. additionwas dropwise added over a period of 20 minutes at 0° C.
2. stirringby stirring at 0° C. for further two hours
3. additionmixed
4. filtrationthe solid was collected by filtration
5. washwashed with ethyl acetate (1.0 mL)
6. customObtained crystals
7. customwere dried under reduced pressure at 50° C.

ORD record

ord-7ea702e94d0c449c8ba87583ebd18249

Source dataset

uspto-grants-2013_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08367857B2