Ethanol → ethyl {3-[(2R)-2-((2R)-2-hydroxy-2-pyridin-3-ylethylamino)propyl]-1H-indol-7-yloxy}acetate
Reaction equation
[OH:1][C@H:2]([C:22]1[CH:23]=[N:24][CH:25]=[CH:26][CH:27]=1)[CH2:3][NH:4][C@H:5]([CH3:21])[CH2:6][C:7]1[C:15]2[C:10](=[C:11]([O:16][CH2:17][C:18]([OH:20])=[O:19])[CH:12]=[CH:13][CH:14]=2)[NH:9][CH:8]=1.S(=O)(=O)(O)O.[CH2:33](O)[CH3:34]>>[OH:1][C@H:2]([C:22]1[CH:23]=[N:24][CH:25]=[CH:26][CH:27]=1)[CH2:3][NH:4][C@H:5]([CH3:21])[CH2:6][C:7]1[C:15]2[C:10](=[C:11]([O:16][CH2:17][C:18]([O:20][CH2:33][CH3:34])=[O:19])[CH:12]=[CH:13][CH:14]=2)[NH:9][CH:8]=1Participants
4
Procedure
{3-[(2R)-2-((2R)-2-Hydroxy-2-pyridin-3-ylethylamino)propyl]-1H-indol-7-yloxy}acetic acid (65 mg, 0.176 mmol) is dissolved in ethanol (5 mL), and thereto are added conc. sulfuric acid (0.1 mL) and Molecular Sieves 4A powder (trade name, 0.3 g), and the mixture is refluxed for 20 hours. After cooling, the insoluble materials are removed by filtration, and a saturated aqueous sodium hydrogen carbonate solution is added to the filtrate. The mixture is evaporated under reduced pressure to remove ethanol, and extracted with ethyl acetate. The organic layer is washed with a saturated brine, dried over sodium sulfate, and concentrated. The residue is purified by silica gel column chromatography (ethanol/chloroform=1/5→1/1). The obtained purified product is dissolved in ethanol (3 mL), and thereto is added 1N HCl/diethyl ether (0.5 mL). The mixture is concentrated under reduced pressure to give the desired ethyl {3-[(2R)-2-((2R)-2-hydroxy-2-pyridin-3-ylethylamino)propyl]-1H-indol-7-yloxy}acetate.2 hydrochloride (63 mg, yield: 76%).