Trimethyl borate → HCID 68670785, Verbindung

To a stirring solution of 23 mL of n-BuLi (1.6 M in hexanes) in 20 mL of THF at −78° C. was added 5.31 g of 1,3-dibromo-5-(dimethoxymethyl)benzene in 80 mL of THF dropwise over a period of about 55 min. After 50 min., 3.2 mL (28.7 mmol) of B(OMe)3 was added, and the solution was stirred at −78° C. for 20 min. The cold bath was removed and stirring continued with gradual warming to r.t. After 1 h, 1 N HCl (45 mL) was added, and the aqueous layer was extracted with EtOAc. The extract was washed with brine, dried over Na2SO4, filtered, and concentrated. To a stirring mixture of crude product in 70 mL of 1N NaOH at 0° C. was added 14.5 mL of H2O2 (30 wt % in H2O) dropwise. After 25 min., 5 N HCl was added to a pH=1, and EtOAc and H2O were added. The organic layer was washed with brine, dried over Na2SO4, filtered, and concentrated. Purification by flash silica gel chromatography (15% EtOAc/hexanes) provided 1.92 g of 3-bromo-5-(dimethoxymethyl)phenol as a pale yellow solid with some impurity.

1. customThe cold bath was removed
2. stirringstirring
3. temperaturewith gradual warming to r.t
4. waitAfter 1 h
5. addition1 N HCl (45 mL) was added
6. extractionthe aqueous layer was extracted with EtOAc
7. washThe extract was washed with brine
8. dry with materialdried over Na2SO4
9. filtrationfiltered
10. concentrationconcentrated
11. additionTo a stirring mixture of crude product in 70 mL of 1N NaOH at 0° C.
12. additionwas added 14.5 mL of H2O2 (30 wt % in H2O) dropwise
13. waitAfter 25 min.
14. addition5 N HCl was added to a pH=1, and EtOAc and H2O
15. additionwere added
16. washThe organic layer was washed with brine
17. dry with materialdried over Na2SO4
18. filtrationfiltered
19. concentrationconcentrated
20. customPurification by flash silica gel chromatography (15% EtOAc/hexanes)

ORD-Eintrag

ord-d1c590ecffec4775abad674201727e62

Quelldatensatz

uspto-grants-2012_10

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08299267B2