Hydrochloric Acid → 2-borono-N-(3,4-dimethyl-5-isoxazolyl)-N-[(2-methoxyethoxy)methyl]benzenesulfonamide

Temperatur

-100 °C

A 1.7 M solution of t-BuLi in pentane (5.0 ml; 8.50 mmol) was added over ~10 minutes to a solution of 2-bromo-N-(3,4-dimethyl-5-isoxazolyl)-N-[(2-methoxyethoxy)methyl]benzenesulfonamide (1.62 g; 3.86 mmol) in THF at -100° C. The temperature was kept below -80° C. during the addition. After stirring 5 minutes at -100° C., trimethylborate (0.53 ml; 4.63 mmol) was added in one portion and the reaction mixture was allowed to warm to room temperature over several hours. At this time, 15 ml of 10% HCl was added and the mixture was extracted with methylene chloride (3×50 ml). The combined organic layers were washed with water (50 ml) and brine (50 ml). Drying (MgSO4), and concentration afforded a yellow oil. The residue was then partitioned between ether (50 ml) and 0.5 N NaOH (20 ml). The ether layer was extracted with 10 ml of 0.5N NaOH. The combined basic layers were washed with ether (50 ml), acidified to pH ~1.5 with saturated KHSO4 solution and extracted with methylene chloride (3×50 ml). Drying (MgSO4) and concentration afforded 1.04 g (70%) of the title product of this step as a light yellow foamy oil.

1. additionThe temperature was kept below -80° C. during the addition
2. temperatureto warm to room temperature over several hours
3. extractionthe mixture was extracted with methylene chloride (3×50 ml)
4. washThe combined organic layers were washed with water (50 ml) and brine (50 ml)
5. customDrying
6. concentration(MgSO4), and concentration
7. customafforded a yellow oil
8. customThe residue was then partitioned between ether (50 ml) and 0.5 N NaOH (20 ml)
9. extractionThe ether layer was extracted with 10 ml of 0.5N NaOH
10. washThe combined basic layers were washed with ether (50 ml)
11. extractionextracted with methylene chloride (3×50 ml)
12. customDrying
13. concentration(MgSO4) and concentration

ORD-Eintrag

ord-cc84c39958744e0c84dc9d423754b48e

Quelldatensatz

uspto-grants-1999_08

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US05939446