Diisopropylamine → 2-(1-methyl-1H-indol-3-yl)pentanoic acid

Under a nitrogen atmosphere, butyl lithium (1.6M, 10 mL, 16 mmol) was added at −78° C. to a solution of diisopropylamine (2.22 mL, 15.84 mmol) in anhydrous tetrahydrofurane. After 25 minutes, a solution of 1-methyl-3-indoleacetic acid (1 g, 5.28 mmol) in tetrahydrofurane (20 mL) was slowly added at −78° C., followed by the addition of propyliodide (1 mL, 10 mmol) after 45 minutes. The mixture was then warmed to room temperature and stirred for 2 hours. The mixture was quenched with water (2 mL) and concentrated in vacuo. The residue was diluted with water (20 mL) and washed with diethyl ether (20 mL). The organic layer was acidified with hydrochloric acid aqueous solution 1N to pH 3 and extracted with dichloromethane (3×10 mL). The organic layer was washed with brine, dried over sodium sulfate, filtered and evaporated under reduced pressure to afford the desired acid (12a) as a brown solid without further purification (1.22 g, 5.28 mmol, 100%).

1. customThe mixture was quenched with water (2 mL)
2. concentrationconcentrated in vacuo
3. additionThe residue was diluted with water (20 mL)
4. washwashed with diethyl ether (20 mL)
5. extractionextracted with dichloromethane (3×10 mL)
6. washThe organic layer was washed with brine
7. dry with materialdried over sodium sulfate
8. filtrationfiltered
9. customevaporated under reduced pressure

ORD record

ord-620df8915c9a4db1aae3863cc959264d

Source dataset

uspto-grants-2016_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09238026B2