Reaktion #316834

Reaktionsgleichung

ammonia

methyl 5-bromo-2-hydroxynicotinate

2-hydroxynicotinic acid

phenylboronic acid

→

5-bromo-3-methoxycarbonyl-1-phenyl-1,2-dihydropyridin-2-one

Ausbeute 60.1%

Lösungsmittel

pyridine

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   Extraktionthe solution was extracted with chloroform
2. 2
   WaschenThe organic layer was washed with brine
3. 3
   Trocknendried over anhydrous magnesium sulfate
4. 4
   SonstigeThe solvent was evaporated
5. 5
   Sonstigethe residue obtained as a solid
6. 6
   Waschenwas washed with diethyl ether

Vorschrift

4.5 g of methyl 5-bromo-2-hydroxynicotinate synthesized by a known method from 2-hydroxynicotinic acid, and 4.7 g of phenylboronic acid were dissolved in 200 ml of tetrahydrofuran. To the mixture were added 705 mg of copper acetate and 1 ml of pyridine, followed by stirring at room temperature for 3 nights in a flow of air. Aqueous ammonia was added to the reaction solution, and the solution was extracted with chloroform. The organic layer was washed with brine, and dried over anhydrous magnesium sulfate. The solvent was evaporated, and the residue obtained as a solid was washed with diethyl ether, to obtain 3.59 g of 5-bromo-3-methoxycarbonyl-1-phenyl-1,2-dihydropyridin-2-one as white crystals. 3.2 g of the product was dissolved in 100 ml of dimethylformamide, to which 7.7 g of tri-N-butyl-(2-pyridyl)tin [CAS No. 59020-10-9] and 240 mg of tetrakistriphenylphosphine palladium were added, followed by stirring at 110° C. for 3 hours in nitrogen atmosphere. After cooling to room temperature, the reaction solution was poured into water, extracted with ethyl acetate. Then, the extract was successively washed with water and brine, dried over anhydrous magnesium sulfate, and then filtered through NH silica gel and silica gel. Then, the filtrate was evaporated, and the resulting precipitates were washed with ether and hexane, and dried, to give 1.59 g of the title compound.

Quelle