Potassium Carbonate → 2-Hydroxy-1,3-benzothiazole-6-carboxylic acid

4-Amino-3-mercaptobenzoic acid (680 mg) was dissolved in tetrahydrofuran (20 ml), and potassium carbonate (550 mg) was added thereto and stirred for 30 minutes at room temperature. The mixture was cooled to −78° C., and triphosgene (400 mg) was added thereto and stirred for 1 hour. The mixture was warmed to room temperature and concentrated under reduced pressure until the volume of the solvent became ⅓. Water (20 ml) and formic acid were added to the concentrate until it became acidic, and precipitated crystals were collected by filtration and washed with water and n-hexane. The crystals were dried under reduced pressure to give the title compound (740 mg, Y.:95%) as white crystals.

1. temperatureThe mixture was cooled to −78° C.
2. stirringstirred for 1 hour
3. temperatureThe mixture was warmed to room temperature
4. concentrationconcentrated under reduced pressure until the volume of the solvent
5. additionWater (20 ml) and formic acid were added to the
6. concentrationconcentrate until it
7. customprecipitated crystals
8. filtrationwere collected by filtration
9. washwashed with water and n-hexane
10. customThe crystals were dried under reduced pressure

ORD-Eintrag

ord-94ef4221512d495fbec3be3264be954f

Quelldatensatz

uspto-grants-2008_03

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07345180B2