Hydrochloric Acid → 3-Ethylisothiazole-4-carboxylic acid

Reaction equation

[CH3:1][C:2]1[C:6]([C:7]([O-:9])=[O:8])=[CH:5][S:4][N:3]=1.[OH-].[Na+].Cl.[CH2:13]1COCC1.CO.O>>[CH2:1]([C:2]1[C:6]([C:7]([OH:9])=[O:8])=[CH:5][S:4][N:3]=1)[CH3:13]

Participants

Reactant 4

HCID 313Hydrochloric Acid

HCID 14798Sodium Hydroxide

HCID 21892291Methanol tetrahydrofuran water

HCID 289502153-Methylisothiazole-4-carboxylate

Product 1

HCID 836821333-Ethylisothiazole-4-carboxylic acid

Conditions

Temperature: 40 °C

Procedure

To a solution of 3-methylisothiazole-4-carboxylate (G-3) (4.73 g, 30.1 mmol) in THF-MeOH-H2O (2:1:1, 50 mL), NaOH (3.61 g, 90.3 mmol) is added and the resulting mixture is stirred at 40° C. for 16 h. The mixture is allowed to cool to RT and then acidified with concentrated HCl to adjust the pH to 2-3. The precipitate is collected by filtration, rinsed with water and dried in vacuo to afford the product, 3 ethylisothiazole-4-carboxylic acid (G-4).