Hydrochloric Acid → Beta-Alanine

関与物質

反応手順

In 10 ml of water, 226 mg (1 m.mol) of carnosine and 84 mg (1 m.mol) of sodium hydrogen carbonate were dissolved. The resultant solution and a solution of 380 mg (1 m.mol) of the N-hydroxysuccinimide ester of oleic acid of high purity obtained in Reference Example in 10 ml of tetrahydroxyfuran added thereto were stirred at normal room temperature with a magnetic stirrer and thus left reacting with each other for 15 hours. From the resultant reaction solution, about 200 mg of N-oleoyl-carnosine of high purity was obtained by acidifying the reaction solution with 6N hydrochloric acid, extracting the acidified reaction product from ethyl acetate, and repeatedly subjecting the extract to a treatment for crystallization with hexane/ethyl acetate (4:1 v/v). This N-oleoyl-carnosine was analyzed by IR, , 1H-NMR and 13C-NMR. In the infrared spectrum, the absorption peaks, region of 2,920 cm-1 and 2,830 cm-1 (CH expansion), originating in oleic acid and the absorption peaks, 1,650 to 1,400 cm-1 (C=C, C=N expansion), originating in imidazole were discernible. Further, a marked decrease was found in the peak, 1,4580 cm-1 (NH deformation), prominent in the chart of carnosine. In the 1H-NMR spectrum, a chemical shift of the C9, C10 cis-form proton in the magnitude of 5.30 ppm originating in oleic acid was discernible. The integral ratio implied the presence of an amide bond between an oleic acid and a carnosine. From the --COOH of oleic acid, the magnitude of chemical shift of the proton of carbon at the alpha position was found to have shifted from 2.30 ppm to 2.00 ppm and that of chemical shift of the proton of carbon at the beta position was found to have shifted from 1.60 ppm to 1.45 ppm. In the 13C-NMR spectrum, the magnitude of chemical shift of the carbon of --COOH of oleic acid was found to have shifted from 180.40 ppm to 170.59 ppm. These results indicate that the oleic acid formed an amide bond with the beta-alanine residue of carnosine. The infrared absorption spectrum is shown in FIG. 1.

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