A colleague and I got to talking yesterday about something that I’m sure many chemists have noticed. Have you ever chased down some reaction or compound in the literature, only to find yourself wild-goosing back to some obscure journal that no one has ever read – just because no one can be bothered to publish a modern procedure?
Here’s how that typically works. You run a SciFinder search on Molecular Structure X. A list with a dozen references comes up. There’s a Tet. Lett. from 2002, but what are the chances it’ll have any spectral data (or anything useful at all?) Ah, there’s one from Tetrahedron in 1995, that should do. So you look over the PDF, search for your compound. . .there it is, number 17. Now to the experimental. . .and you find in the first paragraph that “Compound 17 was prepared according to a published procedure”, footnote thirty-eight. And the footnote is to. . .ay, it’s to a Chem. Ber. paper from 1932. Ausgezeichnet!
Oh-kay. Back to that SciFinder reference list. How about that Tet. Lett. paper? Nope, on inspection, it turns out to reference the 1995 paper you just looked at. What else? There’s a JOC from 1984, let’s try that. Good ol’ JOC, solid stuff. Well, digging up that PDF, you find that it refers to a 1980 paper from the same group from Synthesis. Hrm. So you chase that one down, there it is, compound 9, and the experimental for it is. . .footnoted to the 1932 paper. Again.
And that’s how it goes. Like as not, you can go through the whole list and find that it’s made of tissue paper where your compound of interest is concerned. The whole presence of the compound in the literature is, in the end, based on some obscure German university’s report from the last days of the Weimar Republic. What’s irritating is that while those 1932 folks clearly must have made the compound, it’s not always easy to get those papers immediately. And chemistry has, in fact, changed a bit since those days. Papers from that era rely on distillation and crystallization: there are no chromatographic purifications, because there was (by our standards) no such thing as chromatrography. Spectral data? Hah! UV/Vis was cutting edge back then. You’ll get a melting point, an adjective-laden description of the appearance of the crystals, and maybe even a note about how the stuff tastes. Great.
You know that the people who re-made the stuff during the last 25 years didn’t steam-distill their product or fractionally crystallize it from some mixture of benzene and carbon disulfide or whatever. They ran a quick column and they took an NMR. So why can’t they publish that data? The only reason I can usually see is laziness. Why bother? It’s a known compound; just reference it and get that manuscript out the door. . .