Hydrochloric Acid → Lidorestat
Reaction equation
[F:1][C:2]1[C:7]2[N:8]=[C:9]([CH2:11][C:12]3[C:20]4[C:15](=[CH:16][CH:17]=[CH:18][CH:19]=4)[N:14]([CH2:21][C:22]([O:24]CC)=[O:23])[CH:13]=3)[S:10][C:6]=2[C:5]([F:27])=[CH:4][C:3]=1[F:28].[OH-].[Na+].Cl>COCCOC>[F:1][C:2]1[C:7]2[N:8]=[C:9]([CH2:11][C:12]3[C:20]4[C:15](=[CH:16][CH:17]=[CH:18][CH:19]=4)[N:14]([CH2:21][C:22]([OH:24])=[O:23])[CH:13]=3)[S:10][C:6]=2[C:5]([F:27])=[CH:4][C:3]=1[F:28]Participants
Reactant 3
Product 1
Reagents, catalysts & solvents 1
Procedure
A solution of give 3-(4,5,7-trifluorobenzothiazol-2-yl)methyl-indole-N-acetic acid, ethyl ester (5.91 g, 14.6 mmol) in 1,2-dimethoxyethane (73 mL, 0.2 M) was cooled to 0° C. and treated with aq. NaOH (1.25 N, 58 mL, 73.1 mmol) in a dropwise manner over 15 min. After the addition was complete, the solution was stirred for an additional 30 min, acidified to pH 3 with 2N HCl, and concentrated under reduced pressure. The residue was dissolved in ethyl acetate (200 mL) and washed with sat'd. aq. NaCl (30 mL). The organic extract was dried over Na2SO4, filtered and concentrated. The resulting material was stirred as a suspension in heptane, filtered and dried to give 3-(4,5,7-trifluorobenzothiazol-2-yl)methyl-indole-N-acetic acid (5.38 g, 98%) as a pale yellow solid: mp 177-178° C.; Rf 0.44 (20% methanol in dichloromethane); 1H NMR (DMSO-d6 300 MHz) δ 7.74-7.65 (m, 1H), 7.53 (d, J=7.5 Hz, 1H), 7.46 (s, 1H), 7.40 (d, J=8.1 Hz, 1H), 7.15 (b t, J=6.9 Hz, 1H), 7.03 (b t, J=7.2 Hz, 1H), 5.03 (s, 2H), 4.65 (s, 2H); LRMS calcd for C18H11F3N2O2S: 376.4; found 375.0 (M−1)−. Anal. Calcd for C18H11F3N2O2S: C, 57.44; H, 2.95; N, 7.44; S, 8.52. Found C, 57.58; H, 2.99; N, 7.38; S, 8.51.
Workup
- additionAfter the addition
- concentrationconcentrated under reduced pressure
- dissolutionThe residue was dissolved in ethyl acetate (200 mL)
- washwashed with sat'd
- extractionThe organic extract
- dry with materialwas dried over Na2SO4
- filtrationfiltered
- concentrationconcentrated
- stirringThe resulting material was stirred as a suspension in heptane
- filtrationfiltered
- customdried
Sources & evidence
- ORD record
- ord-1f2d2624f1b4497dbe23cc2fbc2db60f
- Source dataset
- uspto-grants-2010_02
- Patent number
- US07659269B2
Reaction notes
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