反应详情

A mixture of 5.0 g of D-glutamic acid and 7.1 g of sodium carbonate was dissolved in a mixture of 170 ml of water and 200 ml of acetonitrile, and a solution of 11 g of N6 -benzyloxycarbonyl-L-lysine N2 -carboxylic anhydride in acetonitrile was added at -10° C. with stirring. The mixture was stirred further for 2 hours at -10° C. The aqueous layer was washed with cold acetonitrile, neutralized, and concentrated under reduced pressure. The residue was purified by CHP20P column chromatograph (0%→50% acetonitrile/water gradient), and recrystallized from dilute alcohol to give 6.3 g of N6 -benzyloxycarbonyl-L-lysyl-D-glutamic acid (mp. 149°-150° C.). An aliquot (6.0 g) of this product and 3.0 g of sodium carbonate were dissolved in a mixture of 100 ml of water and 40 ml of THF, and with stirring under ice cooling, a THF solution of 3.2 g of N-(nicotinoyloxy)succinimide was added. The mixture was stirred at room temperature for 2 hours. The reaction mixture was neutralized and concentrated under reduced pressure. The residual solution was adjusted to pH 2 and subjected to CHP20P column chromatography (0%→60% acetonitrile/water gradient). Fractions containing the desired product were concentrated to dryness under reduced pressure to give 4.8 g of N2 -nicotinoyl-N6 -benzyloxycarbonyl-L-lysyl-D-glutamic acid. An aliquot (4.0 g) of this product was stirred in acetic anhydride (100 ml) for 2 hours and concentrated to dryness under reduced pressure at a low temperature, and the residue was dissolved in 50 ml of methylene chloride. The solution was washed with water and dried, and the solvent was evaporated to give 3.5 g of roughly purified N2 -nicotinoyl-N6 -benzyloxycarbonyl-L-lysyl-D-glutamic anhydride. The resulting anhydride (3.5 g) was added to a solution of 1.2 g of (2S,3aS,7aS)octahydro-1H-indole-2-carboxylic acid in 15 ml of pyridine, and the mixture was stirred at room temperature for 2 hours. The reaction mixture was concentrated to dryness under reduced pressure at room temperature. The residue was dissolved in water, and the pH of the solution was adjusted to 2. The solution was subjected to CHP20P column chromatography (0%→60% acetonitrile/water gradient). Fractions containing the desired product were concentrated to dryness under reduced pressure to give 1.3 g of (2S,3aS,7aS)-1-(N2 -nicotinoyl-N6 -benzyloxycarbonyl-L-lysyl-gamma-D-glutamyl)octahydro-1H-indole-2-carboxylic acid. This compound was dissolved in 25 ml of ethanol, and 1.2 of ammonium formate and 0.5 g of 10% palladium carbon were added. The mixture was stirred at room temperature for 3 hours. The catalyst was removed by filtration, and the mother liquor was concentrated to dryness under reduced pressure. The residue was purified by CHP20P column chromatography (0%→60% acetonitrile/water gradient), and lyophilized to give 0.8 g of the same final product as obtained in method (a) above.

1. concentrationThe reaction mixture was concentrated to dryness under reduced pressure at room temperature
2. dissolutionThe residue was dissolved in water
3. additionFractions containing the desired product
4. concentrationwere concentrated to dryness under reduced pressure