Reaktion #1704500

Reaktionsgleichung

5-bromo-2-ethoxy-pyridine

4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-3,6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester

Cs2CO3

→

desired product

6-Ethoxy-3′,6′-dihydro-2′H-[3,4′]bipyridinyl-1′-carboxylic acid tert-butyl ester

Lösungsmittel

DMF

H2O

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeAfter that time, the solvent is evaporated
2. 2
   Waschenwashed with brine
3. 3
   TrocknenAfter drying over sodium sulphate
4. 4
   Sonstigethe solvent is removed in vacuo
5. 5
   Sonstigethe residue is purified by column chromatography (silica gel; gradient PE/EtOAc 20:1→10:1)

Vorschrift

Under inert gas atmosphere 5.00 g (23.3 mmol) 5-bromo-2-ethoxy-pyridine are added to a mixture of 7.19 g (23.3 mmol) 4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-3,6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester, 95 mg (1.2 mmol) PdCl2(dppf)xCH2Cl2 and 15.2 g (46.5 mol) Cs2CO3 in 50 mL DMF and 10 mL H2O. The mixture is stirred for 12 h at 80° C. After that time, the solvent is evaporated, the residue taken up in DCM and washed with brine. After drying over sodium sulphate, the solvent is removed in vacuo and the residue is purified by column chromatography (silica gel; gradient PE/EtOAc 20:1→10:1) to yield the desired product which was directly used in the next step.

Quelle