Trimethyl borate → Dimethyl 2-(2-dimethylaminoethyl)benzeneboronate

Temperature

-70 °C

19.0 g (83.2 mmol) of the [2-(2-bromophenyl)ethyl]dimethylamine prepared according to example 10 (2nd stage) were dissolved in 300 ml tetrahydrofuran and the solution was cooled to −70° C. in a cooling bath (isopropanol/dry ice). 60 ml (95.7 mmol) butyllithium solution (1.6 M in hexane) were added dropwise under nitrogen such that the temperature did not rise above −60° C. After the mixture had been stirred at −70° C. for two hours, 28 ml (250 mmol) trimethyl borate were also added dropwise such that the temperature did not rise above −60° C. The mixture was warmed to 25° C. in the course of 15 hours and the solution was concentrated on a rotary evaporator (500-10 mbar) without heat being supplied. The residue was taken up in 200 ml n-hexane, the mixture was stirred for one hour and filtered over an inert gas frit under nitrogen and the filtrated was concentrated on a rotary evaporator (500-10 mbar) without heat being supplied. 14.1 g dimethyl 2-(2-dimethylaminoethyl)benzeneboronate (76.5% of theory) were obtained in this manner.

1. customdid not rise above −60° C
2. customdid not rise above −60° C
3. temperatureThe mixture was warmed to 25° C. in the course of 15 hours
4. concentrationthe solution was concentrated on a rotary evaporator (500-10 mbar)
5. temperaturewithout heat
6. stirringthe mixture was stirred for one hour
7. filtrationfiltered over an inert gas frit under nitrogen
8. concentrationthe filtrated was concentrated on a rotary evaporator (500-10 mbar)
9. temperaturewithout heat

ORD record

ord-d3ffc947b4884017b6f0e1a59cfcd611

Source dataset

uspto-grants-2004_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06710080B2