Chlorotrimethylsilane → 6-[4-(N-acetyl-L-prolylamino)phenyl]-1,2-dihydro-2-oxonicotinic acid

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Reaction Steps

To a suspension of 5.75 g (25 m mol) 6-(4-aminophenyl)-1,2-dihydro-2-oxonicotinic acid and 175 ml of dichloromethane, 10.2 ml (75 m mol) triethylamine and 9.5 ml (75 m mol) chlorotrimethylsilane are added and the reaction mixture stirred at room temperature for 1 hour. To a solution of 7.86 g (50 m mol) of N-Acetyl-L-proline in 100 ml of dichloromethane at -10° C., 5.5 ml (50 m mol) of N-methylmorpholine and 6.5 ml (50 m mol) of isobutyl chloroformate are added and stirred at -10° C. for 1/2 hour. To this cold mixed anhydride mixture is added the silylated 6-(4-aminophenyl)-1,2-dihydro-2-oxonicotinic acid and the resulting mixture is stirred for 3 hrs in an ice bath and overnight at room temperature. Next, 25 ml of isopropanol is added to the reaction mixture and stirred. The reaction mixture is evaporated and the residue is triturated with ice and water. The solid is collected by filtration and washed with water, isopropanol and ether to yield 4.82 g of 6-[4-(N-Acetyl-L-prolylamino)phenyl]-1,2-dihydro-2-oxonicotinic acid, m.p. 288°-290° dec. From the filtrate an additional 3.94 g of product is obtained.

Provenance & Evidence