Int J Cosmet Sci. 2005 Feb;27(1):11-6. doi: 10.1111/j.1467-2494.2004.00246.x.

Eco-friendly methodologies for the synthesis of some aromatic esters, well-known cosmetic ingredients.

International journal of cosmetic science

C Villa, S Baldassari, R Gambaro, E Mariani, A Loupy

PMID: 18492177 DOI: 10.1111/j.1467-2494.2004.00246.x

Abstract

Solid-liquid solvent-free phase transfer catalysis (PTC) and acidic catalysis in dry media were applied, with noticeable improvement and simplification over classical procedures in a Green Chemistry context, to the synthesis of some aromatic esters useful as cosmetic ingredients: 3-methylbutyl 4-methoxycinnamate, 2-ethylhexyl 4-methoxycinnamate, 2-ethylhexyl 4-(dimethylamino)benzoate and 2-ethylhexyl salicylate, well-known ultraviolet B sunscreen filters; 4-isopropylbenzyl salicylate, UV absorber and cutaneous antilipoperoxidant; propyl 4-hydroxybenzoate and butyl 4-hydroxybenzoate (parabens), antimicrobial agents. The reactions were performed under microwave (MW) activation and conventional heating. The best results for the synthesis of cinnamic, salicylic and 4-(dimethylamino)benzoic esters were achieved by in situ preformed carboxylates alkylation with alkyl bromides using PTC. The 4-hydroxybenzoates were obtained in good yields by classical esterification of the acid with alcohols using a simple heterogeneous mixture of reagents with catalytic amounts of p-toluenesulfonic acid (PTSA). The comparisons of yields and thermal profiles under either MW or conventional heating were studied and reported.

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• Journal Article