Ethyl 2- propanoate

Convincing evidence that ester hydrolysis in base proceeds by the second of these two paths namely nucleophilic acyl substitution has been obtained from several sources In one experiment ethyl propanoate labeled with 0 m the ethoxy group was hydrolyzed On isolating the products all the 0 was found m the ethyl alcohol there was no 0 enrichment m the sodium propanoate... 

The saponification of 0 labeled ethyl propanoate was desenbed in Section 20 11 as one of the significant expenments that demonstrated acyl-oxygen cleavage in ester hydrolysis The 0 labeled ethyl propanoate used in this expenment was prepared from 0 labeled ethyl alcohol which in turn was obtained from acetaldehyde and 0 enriched water Wnte a senes of equations... 

The mechanism shown in Figure 21.7 is supported by isotope-labeling studies. When ethyl propanoate labeled with lsO in the ether-like oxygen is hydrolyzed in aqueous NaOH, the l80 label shows up exclusively in the ethanol product. None of the label remains with the propanoic acid, indicating that saponification occurs by cleavage of the C-OR bond rather than the CO—R bond. 

We said in Section 21.6 that mechanistic studies on ester hydrolysis have been carried out using ethyl propanoate labeled with lsO in the etherlike oxygen. Assume that Odabeled acetic acid is your only source of isotopic oxygen, and then propose a synthesis of the labeled ethyl propanoate. 

What product would you obtain from Claisen condensation of ethyl propanoate ... 

Various diastereoselective Michael reactions are based on y-bromo-, y-alkyl-, or y-alkoxy-2(5//)-furanones following the trans-face selectivity shown in Section 1.5.2.3.1.2. Thus the lithium enolates of esters such as ethyl propanoate, ethyl a-methoxyacetate and ethyl a-phenylacetate add to methoxy-2(5/f)-furanone with complete face selectivity269-273 (see Section 1.5.2.4.4.2.). 

Each reaction has a unique value of rate constant k. For example, the value of k in Worked Example 8.2 would have been different if we had chosen ethyl formate, or ethyl propanoate, or ethyl butanoate, etc., rather than ethyl ethanoate. The value of k depends ultimately on the Gibbs function of forming reaction intermediates, as discussed below. 

Ethanol and propanoic acid react to form the ester ethyl propanoate, which has the odour of bananas. 

CH3CH2COOCH2CH3 + H20(,) At 50°C, Kc for this reaction is 7.5. If 30.0 g of ethanol is mixed with 40.0 g of propanoic acid, what mass of ethyl propanoate will be present in the equilibrium mixture at 50°C ... 

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