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Abstract

A novel process for the manufacture of a cinnamic acid derivative of the formula ##STR1## wherein R.sup.1 signifies hydrogen or C.sub.1-8 -alkyl and R.sup.2 signifies hydrogen, C.sub.1-10 -alkyl, C.sub.1-10 -hydroxyalkyl or C.sub.1-4 -alkoxy-C.sub.1-10 -alkyl, is described in which a 4-R.sup.1 O-halobenzene is reacted with acrylic add or an acrylic acid ester CH.sub.2 .dbd.CHCOOR.sup.2 using a heterogeneous palladium catalyst in the presence of the alkanoic acid ammonium salt formed from a C.sub.2-5 -alkanoic acid and an aliphatic mono-, di- or trialkylamine or heterocyclic amine. In the case of the manufacture of the cinnamic acid derivative I in which R.sup.2 signifies hydrogen, the reaction can be carried out in the presence of the amine in place of the alkanoic acid ammonium salt. A further aspect of the described invention comprises reacting the 4-R.sup.1 O-iodobenzene with the product of the Michael addition of an acrylic acid ester CH.sub.2 .dbd.CHCOOR.sup.2', wherein R.sup.2' has the above significance of R.sup.2 except hydrogen, with an aliphatic or heterocyclic primary of secondary amine using a heterogeneous palladium catalyst and in the presence of a C.sub.2-5 -alkanoic add in order to manufacture the above cinnamic add derivatives with the exception of the substituted cinnamic acid itself. In view of their UV-B absorbing properties the thus-manufactured cinnamic acid derivatives are suitable as UV-B filters for cosmetic agents, e.g. sunscreen agents.

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First Claim