Trimethyl borate → HCID 66953917, compound

Temperature

-65 °C

1-Fluoro-2,3-methylenedioxybenzene (5.0 g, 35.7 mmol) was dissolved in THF (70 mL) and the solution cooled to −65° C. in a dry ice acetone bath. n-Butyl lithium (2.5 g, 15.7 mL, 39.3 mmol) was added to the solution via syringe with stirring. The reaction was allowed to warm to −35° C. over 1 hour then re-cooled to −65° C. and treated with trimethylborate (4.1 g, 39.3 mmol) via syringe. The reaction was allowed to warm slowly to room temperature then quenched with 1N HCl (50 mL), stirred for 15 minutes then diluted with ether and the layers separated. The organic layer was extracted with 1N sodium hydroxide and this extract separated from the ether and acidified with 1N hydrochloric acid. The acidic aqueous layer was extracted with two portions of ether and these combined ether extracts were dried (sodium sulfate), filtered and concentrated to a oily solid which was triturated with methylene dichloride. The resulting solid was collected by filtration, washed with methylene dichloride and dried to give 1-fluoro-2,3-methylenedioxyphenylboronic acid (1.4 g, 7.6 mmol) as a tan solid: 1H NMR (DMSO-d6): δ 8.05 (bs, 2H), 7.08 (dd, 1H), 6.76 (d, 1H), 6.08 (s, 2H).

1. temperatureto warm to −35° C. over 1 hour
2. temperaturethen re-cooled to −65° C.
3. temperatureto warm slowly to room temperature
4. customthen quenched with 1N HCl (50 mL)
5. stirringstirred for 15 minutes
6. additionthen diluted with ether
7. customthe layers separated
8. extractionThe organic layer was extracted with 1N sodium hydroxide
9. customthis extract separated from the ether
10. extractionThe acidic aqueous layer was extracted with two portions of ether
11. dry with materialthese combined ether extracts were dried (sodium sulfate)
12. filtrationfiltered
13. concentrationconcentrated to a oily solid which
14. customwas triturated with methylene dichloride
15. filtrationThe resulting solid was collected by filtration
16. washwashed with methylene dichloride
17. customdried

ORD record

ord-90a8dae0cfc843a8b470bac9bc9a2526

Source dataset

uspto-grants-2008_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07314849B2