1,2-Dibromoethane → 6'-Bromo-1'H-spiro[cyclopropane-1,3'-indole]-2'-one

Temperature

0 °C

A solution of 6-bromoindolin-2-one (2 g, 9.43 mmol) and diisopropylamine (2.00 g, 2.82 ml, 19.8 mmol) in tetrahydrofuran (16 ml) was cooled to −25° C. and a solution of nBuLi (1.6 M in hexane, 23.6 ml, 37.7 mmol) was added dropwise. The reaction mixture was warmed to 0° C. and a solution of 1,2-dibromoethane (5.32 g, 2.44 ml, 28.3 mmol) in tetrahydrofuran (2 ml) was added dropwise. The reaction mixture was warmed to room temperature, stirred for 20 hours and carefully quenched with brine (2 ml) and conc. HCl (2 ml, ice bath). The reaction mixture was diluted with tert-butyl methyl ether and water. The aqueous phase was extracted with tert-butyl methyl ether, the combined organic phases were washed with brine and dried over sodium sulfate. The solvent was evaporated and the residue purified by silica gel chromatography using ethyl acetate/heptane as eluent. The title compound was obtained as red crystals (1.11 g).

1. temperatureThe reaction mixture was warmed to room temperature
2. customcarefully quenched with brine (2 ml) and conc. HCl (2 ml, ice bath)
3. additionThe reaction mixture was diluted with tert-butyl methyl ether and water
4. extractionThe aqueous phase was extracted with tert-butyl methyl ether
5. washthe combined organic phases were washed with brine
6. dry with materialdried over sodium sulfate
7. customThe solvent was evaporated
8. customthe residue purified by silica gel chromatography

ORD record

ord-f0c690ab429340f0885379580e5d86eb

Source dataset

uspto-grants-2015_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09221816B2