[CH2:1]([N:4]([CH2:22][CH2:23][CH3:24])[C:5]([C:7]1[CH:8]=[C:9]([CH:14]=[C:15]([C:17]2[CH:21]=[CH:20][S:19][CH:18]=2)[CH:16]=1)[C:10]([O:12]C)=[O:11])=[O:6])[CH2:2][CH3:3]>C1COCC1.CO.[OH-].[Na+].O>[CH2:22]([N:4]([CH2:1][CH2:2][CH3:3])[C:5]([C:7]1[CH:8]=[C:9]([CH:14]=[C:15]([C:17]2[CH:21]=[CH:20][S:19][CH:18]=2)[CH:16]=1)[C:10]([OH:12])=[O:11])=[O:6])[CH2:23][CH3:24]A mixture of methyl 3-[(dipropylamino)carbonyl]-5-(3-thienyl)benzoate (XLIX, step 3, 0.31 g, 0.88 mmol) in THF/methanol/sodium hydroxide (3/1/1, 5 mL) is stirred at 40 degrees C. for 2 hours. The reaction is cooled to 20-25 degrees C., diluted with water and extracted with ethyl acetate. The aqueous phase is acidified to pH=4 and extracted with ethyl acetate. The organic phase is washed with water and saline, dried over magnesium sulfate and concentrated under reduced pressure to give 3-[(dipropylamino)carbonyl]-5-(3-thienyl)benzoic acid (IX-L), ESI-MS (m/z) [M+H]+=332.
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