Dear friend Giancarlo Toselli

Hello there Giancarlo Toselli! While I can't access real-time data or images, I can certainly help you understand the synthesis of Sulindac.

Sulindac is a nonsteroidal anti-inflammatory drug (NSAID). The synthesis of Sulindac involves a few key steps. One common route is the reaction of indene with chlorosulfonyl isocyanate to form an acylindene intermediate. This intermediate is then reacted with an appropriate nucleophile, often an amine, to form the final product, Sulindac.

Regarding the specific issue you Giancarlo Toselli mentioned about the condensation after the formation of the acyl-indene, it would be helpful to understand the exact reaction conditions and mechanism. The choice of base and solvent can influence the reaction outcome.

It's interesting that you're observing deprotonation at the cyclopentene carbon rather than the expected alpha to the ester carbonyl. Reaction mechanisms can sometimes be influenced by steric effects, electronic effects, and the nature of the base and solvent.

If you Giancarlo Toselli provide more details about the specific reaction conditions and the mechanism you're following, I might be able to offer more insights or potential explanations. Feel free to share more details, or let me know if there's anything else you're curious about!

Dear Giancarlo Toselli ,

here is my try of a non-ChatGPT answer to your question.

When depronating the intermediate, you obtain an anion. If the proton is removed from the ring, you can draw more mesomeric boundary structures (indicating that this is a more stable anion) compared with the intermediate that is deprotonated at the alpha carbon.

I hope, you understand what I mean. ;)

Dear Paul Körner thank you for the answer. I'm not very active in this platform, so I've just noticed that you answered me. After my question I did some researches and I've seen that the indene is way more acid than an alpha-ester-hydrogen, so you are right. Thanks again.