Sulfuric Acid → 3-Cyanophenylboronic acid

Temperature

-78 °C

In 100 ml of anhydrous tetrahydrofuran, was dissolved 20 g of 3-bromobenzonitrile. To the resulting solution, was added 37.6 ml of triisopropoxyborane under a nitrogen atmosphere. The formed solution was cooled to −78° C., and 98.3 ml of a 1.6 M solution of n-butyllithium in hexane was dropped thereinto under stirring for about 30 minutes. After stirring the resulting mixture at room temperature for 30 minutes, the mixture was then cooled to 0° C., and 220 ml of a 4 M sulfuric acid was added. The prepared solution was refluxed overnight and subsequently recooled to 0C. To the cooled solution, was added 340 ml of a 5 M aqueous solution of sodium hydroxide. The resulting solution was extracted with 200 ml of diethyl ether, and an aqueous layer was separated. To the aqueous layer, was added a 6 M hydrochloric acid until pH attained 2. The resulting mixture was extracted with 300 ml of ethyl acetate twice. The extract was dried over magnesium sulfate, and the solvent was then evaporated. The resulting crude product was recrystallized from dimethylformamide-water to provide 11.6 g (72%) of the title compound as a needlelike light-yellow crystal.

1. stirringAfter stirring the resulting mixture at room temperature for 30 minutes
2. temperaturethe mixture was then cooled to 0° C.
3. temperatureThe prepared solution was refluxed overnight
4. extractionThe resulting solution was extracted with 200 ml of diethyl ether
5. customan aqueous layer was separated
6. additionTo the aqueous layer, was added a 6 M hydrochloric acid until
7. extractionThe resulting mixture was extracted with 300 ml of ethyl acetate twice
8. dry with materialThe extract was dried over magnesium sulfate
9. customthe solvent was then evaporated
10. customThe resulting crude product was recrystallized from dimethylformamide-water

ORD record

ord-5ebf88fc8f1346e581c7d254647100a1

Source dataset

uspto-grants-2003_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06538137B1