Sodium Hydroxide → 3-Methoxy-4-(4-methyl-3-thienyl)benzoic acid

HRID 400759Notes

Reaction equation

[CH3:1][O:2][C:3]1[CH:4]=[C:5]([CH:10]=[CH:11][C:12]=1[C:13]1[C:17]([CH3:18])=[CH:16][S:15][CH:14]=1)[C:6]([O:8]C)=[O:7].[OH-].[Na+]>CCO.O>[CH3:1][O:2][C:3]1[CH:4]=[C:5]([CH:10]=[CH:11][C:12]=1[C:13]1[C:17]([CH3:18])=[CH:16][S:15][CH:14]=1)[C:6]([OH:8])=[O:7]

Participants

Conditions

Temperature: 60 °C

Procedure

To a solution of methyl 3-methoxy-4-(4-methyl-3-thienyl)benzoate obtained in step 1 (2.30 g; 8.77 mmol) in EtOH (70 mL), was added at RT an aqueous solution of sodium hydroxide (5 M; 5.26 mL; 26.31 mmol). The reaction mixture was stirred at 60° C. for one hour. The reaction mixture was concentrated under vacuum to give a brown solid. It was taken up in water and the aqueous phase was washed twice with EtOAc. Aqueous phase was acidified with concentrated HCl (2 mL) to pH 2. Then it was concentrated under vacuum until a precipitate was formed (⅓ of volume). The suspension was filtered off and dried under vacuum, affording the title compound as a brown solid (1.81 g, 83% for 2 steps). 1H NMR: (DMSO-d5) δ 13.05 (s, 1H), 7.62-7.59 (m, 2H), 7.40-7.39 (d, J=3.23 Hz, 1H), 7.32-7.29 (d, J=7.48 Hz, 1H), 7.25-7.23 (m, 1H), 3.82 (s, 3H), 2.99 (s, 3H). LC/MS (Method A): 248.8 (M+H)+; 246.9 (M−H)−. HPLC (Method A) Rt 3.99 min (Purity: 97.4%).

Workup

concentrationThe reaction mixture was concentrated under vacuum
customto give a brown solid
washthe aqueous phase was washed twice with EtOAc
concentrationThen it was concentrated under vacuum until a precipitate
customwas formed (⅓ of volume)
filtrationThe suspension was filtered off
customdried under vacuum

Sources & evidence

ORD record: ord-b0d67dde0357430d9243a814c95410e0
Source dataset: uspto-grants-2014_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08741923B2

Reaction notes

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