Hydrochloric Acid → 2-Chloro-1,3-benzothiazole-6-carbonitrile

HRID 1944655Notes

Reaction equation

HRID 1944655 reaction equation
[ClH:1].N[C:3]1[S:4][C:5]2[CH:11]=[C:10]([C:12]#[N:13])[CH:9]=[CH:8][C:6]=2[N:7]=1.N([O-])=O.[Na+]>O>[Cl:1][C:3]1[S:4][C:5]2[CH:11]=[C:10]([C:12]#[N:13])[CH:9]=[CH:8][C:6]=2[N:7]=1

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 43271392-Aminobenzothiazole-6-carbonitrileHCID 23668193Sodium Nitrite

Product 1

HCID 219858592-Chloro-1,3-benzothiazole-6-carbonitrile

Reagents, catalysts & solvents 1

HCID 962WaterSolvent3×

Conditions

Temperature
-5 °C

Procedure

To a mixture of 4-aminobenzonitrile (23.6 g, 0.2 mol) and ammonium rhodanate (30.4 g, 0.4 mol) was added glacial acetic acid (600 mL) and the resulting solution was cooled to 13.5° C. on an ice-bath. A mixture of bromine and glacial acetic acid was added drop-wise and slowly. The resulting mixture was stirred for 1 hour at 13.5° C. and filtered. The filter cake was washed with glacial acetic (6×100 mL) and placed in hot water (1000 mL) with stirring. The mixture was filtered and pH of the filtrate was adjusted to 7 with a saturated sodium carbonate solution. The precipitate was isolated and dried to give 19.5 g (56%) of 2-aminobenzothiazole-6-carbonitrile. A mixture of concentrated hydrochloric acid (113 mL) and water (52 mL) was heated at 90° C. while 2-aminobenzothiazole-6-carbonitrile (19 g, 0.108 mol) was added. The mixture was cooled to −5° C. on an ice-bath and a solution of sodium nitrite (7.72 g, 0.112 mol) in water (20 mL) was added drop-wise, keeping the temperature below than 0° C. When addition was complete the mixture was stirred for 0.5 hour and a solution of CuCl2 (16 g) in water (108 mL) was added drop-wise. When addition was complete the mixture was stirred for 10 min, and the ice-bath was removed. Stirring was continued for 2 h and the mixture was cooled to room temperature. The mixture was filtered and the solid was washed to neutrality with water and dried. This afforded 12.8 g (61%) of 2-chlorobenzothiazole-6-carbonitrile. 1H-NMR δ 8.14 (s, 1H), 8.03 (d, 1H), 7.75 (d, 1H).

Workup

  1. additionwas added
  2. custombelow than 0° C
  3. additionWhen addition
  4. additionWhen addition
  5. stirringwas stirred for 10 min
  6. customthe ice-bath was removed
  7. stirringStirring
  8. waitwas continued for 2 h
  9. temperaturethe mixture was cooled to room temperature
  10. filtrationThe mixture was filtered
  11. washthe solid was washed
  12. customdried

Sources & evidence

ORD record
ord-163a5f9bb5e342cf9d94d8eb2cc7d1fc
Source dataset
uspto-grants-2013_03
Patent number
US08394842B2

Reaction notes

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