Potassium Hydroxide → 2-Methyl-4-(2-methylphenyl)-5-thiazolecarboxylic acid

HRID 474352Notes

Reaction equation

HRID 474352 reaction equation
C([O:3][C:4]([C:6]1[S:10][C:9]([CH3:11])=[N:8][C:7]=1[C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][C:13]=1[CH3:18])=[O:5])C.[OH-].[K+]>CO>[CH3:11][C:9]1[S:10][C:6]([C:4]([OH:5])=[O:3])=[C:7]([C:12]2[CH:17]=[CH:16][CH:15]=[CH:14][C:13]=2[CH3:18])[N:8]=1

Participants

4

Reactant 2

HCID 14797Potassium HydroxideHCID 53440888Ethyl 2-methyl-4-(2-methylphenyl)-1,3-thiazole-5-carboxylate

Product 1

HCID 224373602-Methyl-4-(2-methylphenyl)-5-thiazolecarboxylic acidYield 81.7%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Conditions

Temperature
50 °C

Procedure

A mixture of 2-methyl-4-o-tolyl-thiazole-5-carboxylic acid ethyl ester (0.84 g, 3.20 mmol, 1.0 equiv) and potassium hydroxide (0.36 g, 6.40 mmol, 2.0 equiv) in 50% aqueous methanol (10 mL) was heated to 50° C. for 5 hours. The mixture was concentrated, and the residue diluted with water and acidified to about pH 1 by the addition of 6N HCl solution. The resultant solution was extracted with ethyl acetate (3×). The combined extracts were dried over magnesium sulphate, filtered, and concentrated under vacuum to afford 0.61 g (81%) of 2-methyl-4-o-tolyl-thiazole-5-carboxylic acid as a solid. LCMS (ESI) m+H=234.0; 1H NMR (400 MHz, CDCl3) δ: 7.32-7.17 (m, 4H), 2.75 (s, 3H), 2.17 (s, 3H).

Workup

  1. concentrationThe mixture was concentrated
  2. additionthe residue diluted with water
  3. additionacidified to about pH 1 by the addition of 6N HCl solution
  4. extractionThe resultant solution was extracted with ethyl acetate (3×)
  5. dry with materialThe combined extracts were dried over magnesium sulphate
  6. filtrationfiltered
  7. concentrationconcentrated under vacuum

Sources & evidence

ORD record
ord-3d34c92c1f40435288c2880da947495d
Source dataset
uspto-grants-2014_01
Patent number
US08637526B2

Reaction notes

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