[F:1][C:2]1[CH:7]=[CH:6][C:5]([CH2:8][C:9]([O:11]C)=[O:10])=[C:4]([C:13]#[C:14][Si](C)(C)C)[CH:3]=1.C1COCC1.CO.O.[OH-].[Li+]>O>[C:13]([C:4]1[CH:3]=[C:2]([F:1])[CH:7]=[CH:6][C:5]=1[CH2:8][C:9]([OH:11])=[O:10])#[CH:14]To a solution of ester 326 (3.30 g, 12.5 mmol) in 1:1 THF/methanol (100 mL) was added lithium hydroxide monohydrate (1.60 g, 38.1 mmol) in water (25 mL) and the mixture was stirred at r.t. for 30 min. It was then partially concentrated; the aqueous residue was washed with ether; then acidified with 3M HCl (aq), extracted with ethyl acetate. The organic extract was washed with water, dried (anhydrous MgSO4), filtered and concentrated to provide acid 327 (2.10 g, 95% yield). 1H NMR (400 MHz, DMSO-d6) δ (ppm): 7.36 (dd, J=8.6, 5.9 Hz, 1H); 7.30 (dd, J=9.2, 2.7 Hz, 1H); 7.21 (dt, J=8.6, 2.7 Hz, 1H); 4.48 (s, 1H); 3.70 (s, 2H). LCMS: (M+Na) 201.1.
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