[Biohazard]

Hi,

I've been trying to react resveratrol with an acryloyl chloride to get a triacrylate version of resveratrol. Reaction is done in THF and triethylamine (TEA) added as the base catalyst to remove HCl. I've tried various stoichiometric ratios, but I keep getting monoacrylate as the predominant product, with some di- and tri-acrylate. I also tried using potassium carbonate instead of TEA, same problem.

Another big issue is that the final product after purification is hard and extremely sticky, and doesn't want to dissolve in anything.

I've done similar reactions with other phenols, and they work very well. Get products as nice crystalline powders of high purity.

Any suggestions?

Thanks.

[discodermolide]

Try changing the reaction solvent. Perhaps acetone, toluene, etc.
I found that with THF (and more so diethyl ether) it likes to hang onto HCl, this can make the product very difficult to crystallise. Perhaps if you have to stick with THF do a solvent change to toluene and rotavap the residue several times with toluene to remove THF/HCl. Your compound does not even have to dissolve in toluene for this.

[Biohazard]

Thanks discodermolide.

I actually do a solvent switch to ethyl acetate (EA), but perhaps I'm doing it incorrectly. Let me elaborate. The reaction occurs in THF. Then I filter out the TEA-HCl salt. Next, evaporate off the THF to get a sticky gooey mess, probably because of what you described. Then I redissolve the mess in EA, wash with 0.1 M HCl and 0.1 M K2CO3 to remove residual TEA, acrylic acid and HCl. Finally, evaporate off EA to again get a sticky mess.

I don't see why I couldn't replace THF in the reaction step, but the new solvent needs to dissolve resveratrol. Ethyl acetate doesn't work. I'll try dissolving resveratrol in acetone later today. Any other solvent that you could suggest?

Just out of curiosity, do you know the reason why THF likes to hold onto HCl, while acetone and toluene don't?

[discodermolide]

THF and other ethers, especially the lower ones tend to be hydroscopic as well. I guess the ether oxygens contribute to holding onto HCl.
Ethyl acetate is also a pest in this regard and usually gives sticky messes.
Other solvents, well you could try DMF, but that's about it.