Reaktion #40875

Reaktionsgleichung

(4-bromobenzyl)-N-valeryl-L-valine

sodium methoxide

2-(1H-tetrazol-5-yl)phenylboronic acid

→

Valsartan

Ausbeute 58.1%

Lösungsmittel

methanol

methanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe reaction is cooled to 20-25° C.
2. 2
   Filtrationthe catalyst is filtered
3. 3
   workup.DISTILLATIONthe methanol distilled in vacuo
4. 4
   workup.DISSOLUTIONThe resulting residue is dissolved in 25 mL of water
5. 5
   Waschenfollowing washing with 25 mL of AcOEt
6. 6
   Extraktionextracted twice with 20 mL of AcOEt
7. 7
   TrocknenThe combined phases of AcOEt are dried with anhydrous Na2SO4
8. 8
   workup.DISTILLATIONdistillation of the solvent the crude product
9. 9
   Sonstigeobtained
10. 10
    Sonstigeis purified by silica gel chromatography (eluent AcOEt/heptane/AcOH 15:5:0.2)

Vorschrift

A mixture made up of 1 g (2.70 mmol) of (4-bromobenzyl)-N-valeryl-L-valine, 0.513 g (2.70 mmol) of 2-(1H-tetrazol-5-yl)phenylboronic acid, 0.120 g of 5% Pd/C in paste (0.028 mmol of palladium) and 0.0084 g (0.032 mmol) of triphenylphosphine in a solution of 4.1 mL (21.5 mmol) of sodium methoxide in 30% methanol and 10 mL of methanol is heated at 70° C. for 10 h. The reaction is cooled to 20-25° C., the catalyst is filtered and the methanol distilled in vacuo. The resulting residue is dissolved in 25 mL of water and, following washing with 25 mL of AcOEt, is acidified to pH 3 with HCl 3N and extracted twice with 20 mL of AcOEt. The combined phases of AcOEt are dried with anhydrous Na2SO4 and following distillation of the solvent the crude product obtained is purified by silica gel chromatography (eluent AcOEt/heptane/AcOH 15:5:0.2) to provide 0.683 g (58%) of Valsartan.

Quelle