Mechanism for decarboxylation

Propose a mechanism for the following transformation. 


[![enter image description here](https://i.stack.imgur.com/yp6wF.png)](https://i.stack.imgur.com/yp6wF.png)


I gather that this mechanism might be similar to decarboxylation of keto acids: 
[![enter image description here](https://i.stack.imgur.com/XxJSQ.jpg)](https://i.stack.imgur.com/XxJSQ.jpg)


However, I am unsure of how to begin. 




In acidic media, the ester carbonyl will be protonated and the carbonyl carbon attacked by a water molecule. The intermediate will have a proton abstracted by a water molecule and the ethoxy group will be protonated (it can happen either by intermolecular reaction with an H3O+ or by an intramolecular reaction with a proton migration from the protonated intermediate after the water attack). The carbonyl is restored and an ethanol molecule leaves the structure. A subsequent proton abstraction by water forms the carboxylic acid, which will then suffer decarboxylation following the mechanism you presented above. (I'm sorry about my ChemDraw, I suck at drawing even on a computer).


[![Reaction](https://i.stack.imgur.com/BUbTH.png)](https://i.stack.imgur.com/BUbTH.png)


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