Hydrochloric Acid → 4-Isothiocyanatobenzoic acid

4-Aminobenzoic acid (5.00 g, 36.5 mmol) was added to a methylene chloride solution (51 mL) of thiocarbonyldiimidazole (8.45 g, 47.4 mmol) and triethylamine (5.6 mL, 40.2 mmol) at an internal temperature of at most 5° C., followed by stirring under cooling with ice for one hour. The mixture was dropped to a separately prepared mixed solution of concentrated hydrochloric acid (12.2 mL, 140.5 mmol) and n-heptane (51 mL) so that the internal temperature became from 25° C. to 30° C., whereupon a pale yellow suspension was obtained. This was stirred under cooling with ice for 3 hours, and the solid was collected by filtration and washed with water (50 mL) to obtain a pale yellow crude product. The obtained crude product was subjected to an operation of washing with water (50 mL) with stirring and collection by filtration twice, followed by drying under reduced pressure to obtain 4-isothiocyanatobenzoic acid as a pale yellow solid (6.23 g, yield: 95%, HPLC purity: 100.0%).

1. temperatureunder cooling with ice for one hour
2. additionThe mixture was dropped to
3. customa separately prepared
4. custombecame from 25° C. to 30° C., whereupon a pale yellow suspension
5. customwas obtained
6. stirringThis was stirred
7. temperatureunder cooling with ice for 3 hours
8. filtrationthe solid was collected by filtration
9. washwashed with water (50 mL)
10. customto obtain a pale yellow crude product
11. customThe obtained crude product
12. washof washing with water (50 mL)
13. stirringwith stirring
14. customcollection
15. filtrationby filtration twice
16. customby drying under reduced pressure

ORD record

ord-84767283ba7e4155a76f92684b0193a9

Source dataset

uspto-grants-2015_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09102602B2