Hydrochloric Acid → (5,6,7,8-Tetrahydronaphthalen-2-yl)boronic acid

Temperature

-69 °C

In a 5 liter three-necked flask, 67.55 g of 6-bromo-1,2,3,4-tetrahydronaphthalene and 1480 ml of dry tetrahydrofurah (THF) were placed and cooled to −70 to −68° C. on a dry ice-acetone bath in a dry nitrogen gas atmosphere. At that temperature, to the mixture, 200 ml of 1.6 M-butyllithium solution in hexane was added dropwise, followed by stirring for 2 hours at −67° C. or below. To borate in 435 ml of dry THF was added dropwise at −70 to −68° C., followed by stirring for 2 hours at −67° C. or below. The reaction mixture was gradually warmed to room temperature and left standing overnight. The resultant reaction mixture was gradually added dropwise to a mixture of 108 ml of HCl and 438 ml of water kept at 10° C. or below, followed by stirring for 1 hour at that temperature. Thereafter, the mixture was subjected to extraction with toluene. The organic layer was washed with water, followed by distilling-off of the solvent under reduced pressure to obtain a residue. The residue was purified by silica gel column chromatography (eluent: toluene/ethyl acetate=2/1) and recrystallized from hexane to obtain 30.4 g of 1,2,3,4-tetrahydronaphthalene-6-boronic acid (Yield: 54.0%).

1. stirringby stirring for 2 hours at −67° C. or below
2. temperatureThe reaction mixture was gradually warmed to room temperature
3. waitleft
4. waitstanding overnight
5. customThe resultant reaction mixture
6. customkept at 10° C. or below
7. stirringby stirring for 1 hour at that temperature
8. extractionThereafter, the mixture was subjected to extraction with toluene
9. washThe organic layer was washed with water
10. customto obtain a residue
11. customThe residue was purified by silica gel column chromatography (eluent: toluene/ethyl acetate=2/1)
12. customrecrystallized from hexane

ORD record

ord-a5aeee0f30034a5791b4f08e2a928540

Source dataset

uspto-grants-2009_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07534506B2