Ethyl acetate cinnamate

As a general guide, however, it may be noted that the following have fairly easily recognisable odours methyl and ethyl formate methyl and ethyl acetate (apples) methyl and ethyl benzoate methyl salicylate (oil of winter-green) and ethyl salicylate methyl and ethyl cinnamate. (It is however usually impracticable to distinguish by odour alone between the methyl and ethyl esters of a particular acid.) Methyl and ethyl o. alate, and methyl and ethyl phthalate are almost odourless. Succinic and tartaric esters have faint odours. 

This step is optional, depending on how critical it is to separate anthocyanins from other polyphenolics in subsequent analysis. The ethyl acetate fraction is enriched in polypheno-lics such as flavonols, procyanidins, and cinnamates. If analysis of this fraction is desired, a cleaner isolate will be obtained if residual water is removed by passing a nitrogen gas stream through the cartridge for 2 to 3 min before applying ethyl acetate. 

Ethyl dnnamate occurs in small amounts in storax.1 It has been prepared by the action of ethyl alcohol on cinnamic acid in the presence of dry hydrochloric or sulfuric acid 2 by the distillation of the copper salt of the monoethyl ester of benzylidene oxalacetic acid3 and by the condensation of ethyl acetate and benzaldehyde in the presence of sodium.4 The method described in the procedure is a slight modification of the one originally described by Claisen.5... 

HCO2C2H5), diethyl carbonate (C2H5OCO2C2H5), ethyl benzoate (C6H5CO2C2H5) and diethyl oxalate (C2H50C0)2. For example, the Claisen condensation between ethyl benzoate and ethyl acetate gives ethyl cinnamate. 

The synthesis of ethyl cinnamates (ethyl 3-phenylpropenoates) by the Claisen condensationinvolves generation of a carbanion, CH.,C02Et, from ethyl acetate or other ester (Scheme 6.19). 

Certain aromatic and heterocyclic olefinic esters ate best prepared by condensation of ethyl acetate and aromatic aldehydes by sodium sand (Claisen). Benzaldehyde in this reaction gives ethyl cinnamate, C,HsCH=CHC03C,H5 (74%). p-Methylbenzaldehyde, furfural, furylactolein, and 2-thiophenecarboxaldehyde have been condensed in a similar manner. 

Problem 21.21 Esters can be condensed with aromatic aldehydes in the presence of alkoxides thus benzaldehyde and ethyl acetate, in the presence of sodium ethoxide, give ethyl cinnamate, C6H5CH==CHCOOC2Hs. Show all steps in the most likely mechanism for this condensation. 

It is interesting that in one case, at least, a condensation related to the Perkin reaction has been stopped at the aldol, stage. When a mixture of benzaldehyde and ethyl acetate was added to an ether solution of sodium triphenyl methyl and the reaction mixture was worked up after one minute, a 26 per cent yield of the aldol (V) was obtained.13 When the reaction was carried out over a longer period of time, ethyl cinnamate was formed.14... 

ArCUO + CHfCO CJI , CtfliCHiCN. In 1890 Ludwig Claisen, who three years earlier had proposed use of sodium ethoxide as a condensing agent, explored the possibility of condensing benzaldehyde with ethyl acetate to produce ethyl cinnamate (3), in possible rivalry with the Perkin reaction. First trials with a... 

Ethyl p-methoxy cinnamate from p-anisic aldehyde and ethyl acetate... 

Ethyl acetate Ethyl butyrate Ethyl caproate Ethyl cinnamate Ethyl heptoate Ethyl laurate Ethyl oxyhydrate Ethyl phenyl acetate Ethyl propionate Ethyl undecylinate Ethyl valerinate Eucalyptol Eugenol Benzyl isobutyrate Benzyl isovalerinate Benzyl methyl... 

For the most part, the results of these calculations are reinforced by solid state structures. A structure of (ethyl cinnamate)2 SnCl4 indicates that both esters are disposed syn and favor the E complex (Fig. 11 A) [34]. Similarly, ethyl acetate complexes with TiCl4 to afford a dimeric structure with bridging chlorides the esters are syn and complexation occurs anti to the ethoxy group (Fig. IIB) [35]. 

---