I left my phone in San Francisco

Mar 27, 2019
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Well, this blog is slightly overdue, since the ACS meeting has been over for nearly a week. But, I think I’m still adjusting back to East Coast time, so clearly I couldn’t be expected to muse on all the interesting talks I saw until now?! Also I’ve been at a loss without my phone, although I have to say, a phone is easier to recover than your heart (but thanks, Tony, for the title suggestion), especially when you just leave it at a friend’s house…

Anyway, as a final wrap-up from me on the meeting: I went to the “Biocatalysis in polymer science; New materials” session for the afternoon on Thursday, and I have to say that I was impressed both by the quality of talks and the number of people listening to them, as Thursday at an ACS meeting does have the reputation of being a bit of a ghost town.

Three talks that particularly interested me:

Atanu Biswas (of the USDA), who is studying soybean oil as a source of polymer starting materials and biodegradable synthons. These oils, which contain multiple double bonds, have proven difficult to substitute in the past, as all kinds of polymers and crosslinked species are generated. He and his colleagues previously tackled the problem of creating monomeric, functionalized oils by first creating the epoxidized molecule, and then reacting it with amines. In this talk, he reported the use of DEAD to generate hydrazine-substituted molecules. They then utilized these compounds in further reactions to generate Diels-Alder products and some polymers.

Sabine Wallner (a postdoc in Richard Gross’ lab) is studying the metathesis of sophorolipids, natural surfactants consisting of two sugars and a lipid chain that sometimes cyclize spontaneously to form a 26-atom ring. Successful polymerization of these compounds, which are excreted by cells, would result in a biodegradable polymer with many potential uses. What was especially interesting about this talk is that ROMP is normally facilitated by ring strain in the monomeric material. Yet the cyclic sophorolipid is unlikely to be strained because of the very large ring size. In any case, they’ve gotten polymers of up to 100 kD, indicating that there is a lot to learn about this system.

Finally, HN Cheng (from Hercules Incorporated, also one of the chairs of the session) gave a great talk on the application of lipases to create polyamides. Their rationale for the project was to create nylon with an additional amine in the backbone so that it would be water soluble. This isn’t possible with regular polymerization conditions, as the secondary amine would react to form a branch point. He told us that his team had been busy trying to make proteases do this reaction, since it’s just the reverse of their normal function, but with no success. When they tried lipases, though, they got nice polymers both because the formation of amide bonds is not so different from ester bonds, and because the cleavage of these bonds is not possible for the lipase. By careful choice of starting materials, they were able to create multiple polymers that just wouldn’t be accessible with standard synthetic techniques.

In addition to the good talks of the session, I was impressed with the discussions that ensued – clearly everyone was paying attention and there were some helpful suggestions for the authors. Congrats to the POLY section for an exciting meeting.

Catherine Goodman (Assistant Editor at Nature Chemical Biology)


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