Reaktion #470768

Reaktionsgleichung

2,3,4-Trimethoxyphenylboronic acid

EtOH

Methyl-3-bromobenzoate

N2

→

2′,3′,4′-Trimethoxy-biphenyl-3-carboxylic acid methyl ester

Ausbeute 59.0%

Lösungsmittel

toluene

water

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstige(The following reaction
2. 2
   SonstigeThe resulting mixture is carefully degassed
3. 3
   Sonstige(5 times alternating vacuum and flushing with N2)
4. 4
   Sonstigethe resulting mixture is again carefully degassed
5. 5
   SonstigePartition the mixture between brine/EtOAc (1+1)
6. 6
   Sonstigeseparate layers
7. 7
   Extraktionextract the aqu
8. 8
   Waschenlayer with EtOAc (3×), wash the combined organic layer with brine
9. 9
   Trocknendry with Na2SO4
10. 10
    Sonstigeremove solvent
11. 11
    SonstigePurify crude product by preparative radial chromatography (silica gel, EtOAc/CyH 1+5)

Vorschrift

(The following reaction is done in an N2 atmosphere.) To a solution of 2,3,4-Trimethoxyphenylboronic acid (42) (1.40 g, 6.60 mmol) in toluene (15.0 mL) is added EtOH (2.0 mL), Pd(PPh3)4 (208 mg, 0.18 mmol) and Na2CO3.10H2O (4.81 g, 16.80 mmol) in water (5.2 mL). The resulting mixture is carefully degassed (5 times alternating vacuum and flushing with N2). A solution of Methyl-3-bromobenzoate (11) (1.29 g, 6.00 mmol) in toluene (9.0 mL) is added by syringe, the resulting mixture is again carefully degassed and stirred overnight at 100° C. Partition the mixture between brine/EtOAc (1+1), separate layers, extract the aqu. layer with EtOAc (3×), wash the combined organic layer with brine, dry with Na2SO4 and remove solvent. Purify crude product by preparative radial chromatography (silica gel, EtOAc/CyH 1+5) to obtain 2′,3′,4′-Trimethoxy-biphenyl-3-carboxylic acid methyl ester (43) as a yellowish oil (1.07 g, 58%). 1H NMR (400 MHz, CDCl3): 3.66 (s, 3H); 3.89 (s, 3H); 3.92 (s, 6H); 6.74 (d, 1H, J=8.6 Hz); 7.03 (d, 1H, J=8.6 Hz); 7.44 (t, 1H, J=7.8 Hz); 7.70 (d, 1H, J=7.6 Hz); 7.97 (d, 1H, J=7.8 Hz); 8.15 (br.s 1H).

Quelle