Potassium Hydroxide → Benzoic acid, 3-amino-2-mercapto-

HRID 1457286Notes

Reaction equation

HRID 1457286 reaction equation
[OH-].[K+].NC1[S:5][C:6]2[C:12]([C:13]([O:15]C)=[O:14])=[CH:11][CH:10]=[CH:9][C:7]=2[N:8]=1>O.O1CCOCC1>[NH2:8][C:7]1[C:6]([SH:5])=[C:12]([CH:11]=[CH:10][CH:9]=1)[C:13]([OH:15])=[O:14]

Participants

5

Reactant 2

HCID 14797Potassium HydroxideHCID 10910742Methyl 2-aminobenzo[d]thiazole-7-carboxylate

Product 1

HCID 10909971Benzoic acid, 3-amino-2-mercapto-

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 312751,4-DioxaneSolvent

Conditions

Temperature
25 °C

Procedure

28.9 g of potassium hydroxide (85%), dissolved in 38 ml of water, are added dropwise to 3:5 g of methyl 2-amino-benzothiazole-7-carboxylate in 38 ml of dioxane under a nitrogen atmosphere in the course of 20 minutes, while stirring and cooling with ice, such that the internal temperature of 25° C. is not exceeded. Thereafter, the mixture is refluxed at a bath temperature of 140° C., and towards the end of the reaction the internal temperature is increased to 170° C. and dioxane is distilled off by means of a descending condenser. The mixture is then cooled to 0° C. and filtered under a nitrogen atmosphere and the residue is rinsed with 30. ml of ice-water. The title compound can be isolated from the filtrate by acidification to pH 5.5, with severe cooling and stirring at a maximum of 0° C., and extraction with ethyl acetateltetrahydrofuran (8:2) and washing with concentrated sodium chloride solution. Because of the risk of the formation of the disulfide, the potassium salt in the filtrate (potassium 3-amino-2-mercapto-benzoate) is preferably further reacted directly.

Workup

  1. additionare added dropwise to 3
  2. temperatureThereafter, the mixture is refluxed at a bath temperature of 140° C.
  3. customtowards the end of the reaction the internal temperature
  4. temperatureis increased to 170° C.
  5. distillationdioxane is distilled off by means of a descending condenser
  6. temperatureThe mixture is then cooled to 0° C.
  7. filtrationfiltered under a nitrogen atmosphere
  8. washthe residue is rinsed with 30

Sources & evidence

ORD record
ord-b22a83e12a5947a5a7b572c4c062f787
Source dataset
uspto-grants-1998_12
Patent number
US05847147

Reaction notes

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