Benzocaine → Ethyl 2-Aminobenzothiazole-6-carboxylate

HRID 864975Notes

Reaction equation

HRID 864975 reaction equation
[NH2:1][C:2]1[CH:12]=[CH:11][C:5]([C:6]([O:8][CH2:9][CH3:10])=[O:7])=[CH:4][CH:3]=1.[S-:13][C:14]#[N:15].[K+].BrBr>C(O)(=O)C>[NH2:15][C:14]1[S:13][C:12]2[CH:11]=[C:5]([C:6]([O:8][CH2:9][CH3:10])=[O:7])[CH:4]=[CH:3][C:2]=2[N:1]=1

Participants

5

Reactant 3

HCID 2337BenzocaineHCID 24408BromineHCID 516872Potassium thiocyanate

Product 1

HCID 601008Ethyl 2-Aminobenzothiazole-6-carboxylateYield 22.9%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

A solution of ethyl 4-aminobenzoate (8.26 g, 0.05 mol) in acetic acid (100 mL) was treated with potassium thiocyanate (14.58 g, 0.15 mol) and stirred 10 minutes at room temperature to dissolve the salt. The resulting solution was cooled in an ice bath and stirred while bromine (2.6 mL, 0.05 mol) was added dropwise over 15 minutes. The cooling bath was removed and the mixture was stirred at room temperature for 2.25 hours. The mixture was stored at 5° C. for 5 hours, then filtered to remove the yellow precipitate. The filter cake was washed with diethyl ether (2×50 mL) and water (2×100 mL) and dried under vacuum to give 2-amino-6-ethoxycarbonylbenzothiazole (2.54 g) as a yellow solid.

Workup

  1. dissolutionto dissolve the salt
  2. temperatureThe resulting solution was cooled in an ice bath
  3. additionwas added dropwise over 15 minutes
  4. customThe cooling bath was removed
  5. stirringthe mixture was stirred at room temperature for 2.25 hours
  6. waitThe mixture was stored at 5° C. for 5 hours
  7. filtrationfiltered
  8. customto remove the yellow precipitate
  9. washThe filter cake was washed with diethyl ether (2×50 mL) and water (2×100 mL)
  10. customdried under vacuum

Sources & evidence

ORD record
ord-1ddfb66e20ef4e5fa57930758d8dd2cd
Source dataset
uspto-grants-1996_10
Patent number
US05565445

Reaction notes

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