4-Bromobenzoic acid → 5-Bromo-2-(4-bromophenyl)-1,3-benzothiazole

HRID 1903555Notes

Reaction equation

HRID 1903555 reaction equation
Cl.[Br:2][C:3]1[CH:8]=[CH:7][C:6]([SH:9])=[C:5]([NH2:10])[CH:4]=1.[Br:11][C:12]1[CH:20]=[CH:19][C:15]([C:16](O)=O)=[CH:14][CH:13]=1.O.CO>S1(CCCC1)(=O)=O>[Br:11][C:12]1[CH:20]=[CH:19][C:15]([C:16]2[S:9][C:6]3[CH:7]=[CH:8][C:3]([Br:2])=[CH:4][C:5]=3[N:10]=2)=[CH:14][CH:13]=1

Participants

5

Reactant 3

HCID 114644-Bromobenzoic acidHCID 202552762-Amino-4-bromobenzene-1-thiol--hydrogen chloride (1/1)HCID 22242641Methanol--water (1/1)

Product 1

HCID 135875765-Bromo-2-(4-bromophenyl)-1,3-benzothiazole

Reagents, catalysts & solvents 1

HCID 31347SulfolaneSolvent

Conditions

Temperature
70 °C

Procedure

A mixture of 20 g (0.083 mole) of 4-bromo-2-aminothiophenol hydrochloride and 270 g of deoxygenated polyphosphoric acid was heated at 70° C. for 4 hours. To this mixture was added a solution containing 22 g (0.11 mole) of p-bromobenzoic acid dissolved in 109 g of sulfolane. The reaction mixture was slowly heated to 200° C. and maintained at that temperature for 1 hour. After cooling, the reaction mixture was poured into a 1:1 water-methanol solution to precipitate the product. The light tan precipitate was filtered, washed with dilute ammonium hydroxide, washed with water, and then air dried. The 2-(4-bromophenyl)-5-bromobenzothiazole was recrystallized from toluene to give 24.5 g (80% of theoretical), m.p. 162°-163° C.

Workup

  1. additionTo this mixture was added a solution
  2. temperatureThe reaction mixture was slowly heated to 200° C.
  3. temperaturemaintained at that temperature for 1 hour
  4. temperatureAfter cooling
  5. customto precipitate the product
  6. filtrationThe light tan precipitate was filtered
  7. washwashed with dilute ammonium hydroxide
  8. washwashed with water
  9. customair dried
  10. customThe 2-(4-bromophenyl)-5-bromobenzothiazole was recrystallized from toluene
  11. customto give 24.5 g (80% of theoretical), m.p. 162°-163° C.

Sources & evidence

ORD record
ord-107440b7545845ca9d5a7430b8a8b596
Source dataset
uspto-grants-1984_03
Patent number
US04436886

Reaction notes

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