Indoline-2-carboxylic acid → 2,3-dihydro-1H-indol-2-ylmethanol

Racemic 2,3-dihydro-1H-indole-2-carboxylic acid (5.0 g, 30.6 mmol) was suspended in methanol (50 ml). Sodium methoxide (1.66 g, 30.6 mmol) was added, and the resulting slurry was stirred several minutes before the solvent was removed in vacuo. The entire sample was suspended in anhydrous tetrahydrofuran (60 ml). Lithium aluminum hydride (1.0M solution in tetrahydrofuran; 30.6 ml, 30.6 mmol) was added dropwise over 15 minutes. The reaction mixture was refluxed for 3 hours. The ice-bath-chilled mixture was then cautiously quenched by dropwise addition of 15 percent aqueous sodium hydroxide (4 ml). The reaction was filtered, and the filtrate was concentrated in vacuo to afford (+)-2-hydroxymethyl-indoline (3.69 g) as a viscous brown oil, used in the next step without further purification. TLC Rf (silica gel plates; u.v. detection, elution with ethyl acetate/hexane=1:4 in volume): 0.15.

1. customwas removed in vacuo
2. temperatureThe reaction mixture was refluxed for 3 hours
3. customwas then cautiously quenched by dropwise addition of 15 percent aqueous sodium hydroxide (4 ml)
4. filtrationThe reaction was filtered
5. concentrationthe filtrate was concentrated in vacuo

ORD record

ord-e3604e8cafcd43ad85898a1551fd3a3b

Source dataset

uspto-grants-1997_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05668145