Reaktionsgleichung
Br[C:2]1[CH:3]=[N:4][CH:5]=[C:6]([O:8][CH2:9][C:10]2[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=2)[CH:7]=1.[B:16](OC(C)C)([O:21]C(C)C)[O:17]C(C)C.C([Li])CCC.Cl>C1(C)C=CC=CC=1.O1CCCC1>[CH2:9]([O:8][C:6]1[CH:7]=[C:2]([B:16]([OH:21])[OH:17])[CH:3]=[N:4][CH:5]=1)[C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1Komponenten
Reaktionsbedingungen
- Temperatur
- -70 °C
Versuchsvorschrift
1.91 g of 3-bromo-5-benzyloxypyridine, under argon, are added to a solution of 2 ml of triisopropyl borate in a mixture of 12 ml of toluene and 3 ml of tetrahydrofuran. The solution is cooled to −70° C. and then 5.42 ml of n-butyllithium (1.6N in hexane) are added dropwise. The reaction medium is stirred for 3 hours, and brought back to −20° C., and 7.23 ml of 2N hydrochloric acid are added dropwise. The reaction mixture is left to return to ambient temperature and poured into distilled water. The aqueous phase is extracted with ethyl acetate, and then the organic phase is washed with a saturated solution of sodium chloride, dried over magnesium sulphate and concentrated under reduced pressure, so as to give 0.21 g of [5-(benzyloxy)pyridin-3-yl]boronic acid in the form of a white powder (adapted from Wenjie Li et al. An Improved Protocol for the Preparation of 3-Pyridyl- and Some Arylboronic Acids J. Org. Chem., (2002), 67(15), 5394-5397), the characteristics of which are the following:
Aufarbeitung
- custombrought back to −20° C.
- waitThe reaction mixture is left
- customto return to ambient temperature
- additionpoured
- distillationinto distilled water
- extractionThe aqueous phase is extracted with ethyl acetate
- washthe organic phase is washed with a saturated solution of sodium chloride
- dry with materialdried over magnesium sulphate
- concentrationconcentrated under reduced pressure
Quellen und Nachweise
- ORD-Eintrag
- ord-d601ff0e341248eba784433b0aeaddd8
- Quelldatensatz
- uspto-grants-2012_11
- Patentnummer
- US08309721B2
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