4-Aminobenzoic Acid → 6-Benzothiazolecarboxylic acid, 2-amino-

HRID 1798992Notes

Reaction equation

HRID 1798992 reaction equation
[NH2:1][C:2]1[CH:10]=[CH:9][C:5]([C:6]([OH:8])=[O:7])=[CH:4][CH:3]=1.[S-:11][C:12]#[N:13].[K+].BrBr>CC(O)=O.O>[NH2:13][C:12]1[S:11][C:3]2[CH:4]=[C:5]([C:6]([OH:8])=[O:7])[CH:9]=[CH:10][C:2]=2[N:1]=1

Participants

6

Reactant 3

HCID 9784-Aminobenzoic AcidHCID 24408BromineHCID 516872Potassium thiocyanate

Product 1

HCID 667406-Benzothiazolecarboxylic acid, 2-amino-

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolvent2×HCID 962WaterSolvent

Conditions

Temperature
25 °C

Procedure

A solution of 4-aminobenzoic acid (1.37 g, 14 mmol) in AcOH (16 mL) may be added with potassium thiocyanate (3.9 g, 40 mmol) and may be stirred for 15 minutes. A solution of bromine (0.5 mL, 10 mmol) in AcOH (6 mL) may then be added slowly into the reaction mixture in water bath, where the temperature may be maintained at about 25° C. The resulting mixture may be stirred overnight. The mixture may then be filtered, and the pale yellow precipitate may then be further recrystallized with the minimal volume of aqueous hydrochloric acid (6 M). A pale yellow product of formula (2) may be collected with the following characterization: 1H NMR (CD3OD, 500 MHz): δ 4.96 (2H, brs), 7.58 (1H, d, J=8.0 Hz), 8.14 (1H, dd, J=8.5 Hz and 1.5 Hz), 8.47-8.47 (1H, m); 13C NMR (CDCl3): δ 12.1, 23.7, 54.6, 85.0, 85.1, 122.5, 123.9, 127.9, 128.3, 132.7, 151.9, 155.3, 168.0, 178.7.

Workup

  1. stirringThe resulting mixture may be stirred overnight
  2. filtrationThe mixture may then be filtered
  3. customthe pale yellow precipitate may then be further recrystallized with the minimal volume of aqueous hydrochloric acid (6 M)
  4. customA pale yellow product of formula (2) may be collected with the following characterization

Sources & evidence

ORD record
ord-ea8db082c3824647b8fe800c17c00ca9
Source dataset
uspto-grants-2013_01
Patent number
US08344007B2

Reaction notes

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