Tetrahydrofuran → 2-Chloro-5-methoxypyridine-3-boronic acid

HRID 1621390

Reaktionsgleichung

Reaktionsgleichung von HRID 1621390
[Li]CCCC.CCCCCC.Br[C:13]1[C:14]([Cl:21])=[N:15][CH:16]=[C:17]([O:19][CH3:20])[CH:18]=1.[B:22](OC(C)C)([O:27]C(C)C)[O:23]C(C)C.C1COCC1>>[Cl:21][C:14]1[C:13]([B:22]([OH:27])[OH:23])=[CH:18][C:17]([O:19][CH3:20])=[CH:16][N:15]=1

Komponenten

6

Edukt 5

HCID 8028TetrahydrofuranHCID 8058HexaneHCID 21531Triisopropyl borateHCID 467388143-Bromo-2-chloro-5-methoxypyridineHCID 178418339Butyllithium

Produkt 1

HCID 467388162-Chloro-5-methoxypyridine-3-boronic acidAusbeute 71 %

Versuchsvorschrift

2.5 M n-BuLi in hexane (3.7 mL, 9.3 mmol) was added slowly to a stirred premixed solution of 3-bromo-2-chloro-5-methoxypyridine (1.73 g, 7.8 mmol) and triisopropyl borate (2.1 mL, 9.3 mmol) in THF (10.0 mL, 122 mmol) at −78° C., and the resulting deep colored mixture was stirred at the same temperature for 1 h and then allowed to warm up to room temperature over 1 h. The reaction was quenched with 1 N NaOH(aq) and then some EtOAc. The separated aqueous layer was acidified with 5N HCl until pH about 5 and then extracted with EtOAc(×2) and the combined organic layers were washed with brine, dried over Na2SO4, and concentrated to give 2-chloro-5-methoxypyridin-3-ylboronic acid (1.0276 g, 71%) as a brown solid. LCMS (API-ES) m/z 188 (M+H)+.

Aufarbeitung

  1. customThe reaction was quenched with 1 N NaOH(aq)
  2. extractionextracted with EtOAc(×2)
  3. washthe combined organic layers were washed with brine
  4. dry with materialdried over Na2SO4
  5. concentrationconcentrated

Quellen und Nachweise

ORD-Eintrag
ord-256e3b84f8bc4fdcb672bff1fa63a78a
Quelldatensatz
uspto-grants-2014_07
Patentnummer
US08772480B2

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