The NMR Laundromat

Source: OPRD / CNRS

The simplest, most practical solutions* are often the best.

I'm reminded of classic papers for pragmatic lab procedures, like Clark Still's on flash chromatography, or Gottlieb & Nudelman's on detecting trace NMR impurities. Everyone has encountered their lab's version of the Kugelrohr setup - run by an old electric kettle and a windshield-wiper motor!

From the ASAP of Organic Process Research and Development comes this handy one-pager: a how-to on cleaning dozens of NMR tubes simultaneously, using glassware readily available in just about any synth lab.

Seeing this instantly triggered a "Well, duh!" moment for me - the amount of time I've stood before a stoppered 500mL vacuum flask impaled with a cannula, washing single tubes by hand...I'm sure it reaches into hours, if not days.

If you try this, leave a comment; I'm really quite interested to see how it turns out. I'd also wonder if OPRD might be angling for other quick one-offs. Couldn't hurt to try, right?

*Of course, I'd be remiss if I didn't point unfamiliar readers to the treasure trove that is Not Voodoo.

Cellphone Charger Electrochemistry

I'm frankly amazed at chemists' rugged pragmatism. Our ilk often repurpose seemingly innocent household items - floodlights, LED strips, paraffin wax - adapting them for making new molecules in interesting ways. Have a peek at this new paper, which appeared* last week in Angewandte Chemie. 

The Aubé group, recently of UNC, wondered whether expensive setups from scientific vendors were potential roadblocks to wide adoption of electrochemistry. Their ideal recipe called for a direct current (DC) source capable of removing two electrons and an H from a lactam to generate an N-acyliminium ion. Looking around, the researchers realized that today's ubiquitous cellphone chargers might just do the trick. Shave back some wires, attach some copper clamps, and presto! Cheap, effective electrochemistry.**

Using their DIY e-chem setup, the Aubé group traps a wide variety of stereochemically-rich acyliminiums as the corresponding methanol adducts (19-93% yields). Now the real fun starts: there's a whole bunch of interesting arylations and other additions to these species one can access using off-the-shelf Lewis acids like titanium tetrachloride or boron trifluoride:

Adapted from Aube, Angewandte Chemie, 2015 ASAP

I'll be excited to see small libraries of diversified products emerge from this work. However, a "one-pot" functionalization - electrochemistry with the desired nucleophile already present - still seems a distant dream.

Hopefully, the apparent ease of operation of "cellphone charger e-chem" prompts other groups to give it a try. If your group dips their toes into this field, please drop me a line in the comments section.

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*Thanks to Professor Brandon Findlay (@Chemtips) for pointing out this paper!

**I'm tickled pink at how many organic synthesis papers these days include photographic records of reaction setups. I'd like to believe that Blog Syn played a small role in advancing this change.