Acetic Anhydride → Ethyl 4-[15-(trifluoromethyl)pentadecylamino]cinnamate

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Reaction Steps

The [4-(polyfluoroalkylamino)phenyl]alkenoic acids may be prepared by condensation of the appropriate aldehydes or by dehydration of the corresponding substituted-phenyl-hydroxyalkanoic acids. For example, ethyl 5-{4-[15-(trifluoromethyl)pentadecylamino]phenyl}-2,4-pentadienoate is obtained by the Wittig reaction of 4-[15-(trifluoromethyl)pentadecylamino]benzaldehyde with the Wittig reagent, triethyl 4-phosphonocrotonate. Alternatively, these alkenoic acids are obtained by heating 4-[N-polyfluoroalkyl-N-(methyl or acetyl)amino]benzaldehydes with the sodium salt of the carbanion of ethyl acetate or with a mixture of ethyl acetate, acetic anhydride and potassium acetate. The second method is illustrated by dehydration of ethyl 3-{4-[15-(trifluoromethyl)pentadecylamino]phenyl}-3-hydroxypropionate to yield ethyl 4-[15-(trifluoromethyl)pentadecylamino]cinnamate.

Provenance & Evidence