| 摘要 |
PROBLEM TO BE SOLVED: To obtain a new benzalmalonate derivative having asymmetrical ester chain lengths, excellent ultraviolet-absorbing properties and photostability, and capable of manifesting high ultraviolet-protecting activities when formulated to a skin preparation for external use, a hair cosmetic or the like. SOLUTION: This compound is a benzalmalonate derivative of formula I [(n)×R<1> O are each a 1-5C alkoxy; (n) is an integer of 1-3; R<2> is methyl or ethyl; R<3> is an 8-12C hydrocarbon], e.g. methyl dodecyl p-methoxybenzalmalonate of formula II. The derivative of formula I is obtained, for example, by subjecting dimethyl malonate or diethyl malonate to an ester-interchange reaction with a compound of the formula R<3> OH to provide an asymmetric malonic ester of formula III, and condensing the obtained asymmetric malonic ester with an aromatic aldehyde of formula IV. The derivative of formula I is excellent in solubility in a base such as a nonpolar oil solution, and preferably used as an active ingredient for an ultraviolet absorber for skin and hair in a form carried on a carrier.
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