Hello, I am currently conducting my Bachelor on a organic synthesis. Here, I first form an acid chloride by the addition of thionyl chloride and Dimethylformamide (which together form the Vilsmeier-Haack reagent) to my starting product (4-hydroxyphenylacetic acid) at room temperature. After, I add Triethylamine (a proton scavenger) and a dimethylamine HCl salt, the latter of which should react with the acid chloride in a amidation reaction. However, upon addition of the DMA.HCl nothing seems to occur and a IR-spec analysis of the final product shows a molecule reminiscent of polyethylene terephthalate (PET). This finding makes me think that there might be a polymerization reaction going on in which the acid chloride reacts with the hydroxy group of 4-hydroxyphenylacetic acid. This would also be able to explain as to why the DMA.HCl would not react in the mixture as all the acid chlorides would have polymerized before the amidation could occur.
Dear Tom,
Maybe you should protect the hydroxyl group before amidation? Otherwise, the starting material 4-hydroxyphenylacetic acid will undergo esterification with itself, catalyzed by the acid chloride.
Or you can use EDCI/DMAP/Et3N to amidate them instead of acid chloride?
Dear Zhu Zile,
Thank you for your response and my apologies for my late one. I'll try to keep you updated (provided that I have the time to go through the synthesis again). I am following a reference paper (DOI: 10.1016/j.rechem.2021.100160) in which they mention the formation of a by-product which is effectively a molecule created through a single cycle of polymerisation. They do not mention any other products being formed however. hence my confusion.
- Badges
- Science topic
- Similar topics
- Biological Science
- Bioecology
- Systems Ecology
- Landscape Ecology
- Connectivity