| 摘要 |
NEW MATERIAL:A urocanic acid derivative of the formula (R1, R2 are H, lower alkyl; X is -CO-, -CHOH-; R is H, lower alkyl) and its salt. EXAMPLE:(E)-3-[1-(1,1-Dimethyl-3-oxobutyl)imidazol-4-yl]propenoic acid. USE:It is useful as a UV absorber. It can be advantageously applied to a variety of preparations such cosmetics for protecting skins from sun light, or a variety of external medicines, because it has high solubility in aqueous medium and a variety of organic solvents, good handleability, low toxicity and high safety. PREPARATION:The reaction of urocaninic acid or its methyl ester with mesityl oxide is carried out in a solvent such as ethanol in the presence of a catalyst, appropriately with heat to give the compound of the formula. The catalyst is, e.g., p-toluenesulfonic acid or sodium hydroxide. |
