Head-Scratching "Sanros" Structures

It's like a crossword puzzle...
Source: Chemistry World

Over at Chemistry World, Duncan Browne posted a review of a new applet version of the Kurti / Czako book Strategic Applications of Named Reactions in Organic Synthesis (for the hip iPhone crowd, the title has been condensed to simply "Sanros"). The trial version allows access to 25 out of the 250 reactions included in paid access. I'm all for chemistry-enabled free software making its way out into the public.

Just one tiny problem: what the heck is that structure? Maybe the atoms were inadverently deleted in transit, or perhaps it's meant as an artistic statement? I can't imagine this molecular graphic falls under Elsevier copyright protection.

In a way, it's like a detective mystery: can you infer what's missing? I took a crack at it myself (see below). I figured the structure on the right was either a dithiane (S,S) or ketal (O,O). The bottom ring could have any combination of N,O,S, so we'll swap in a morpholine. The aromatic? Gotta be a pyridine. Uh-oh, there could be anything terminating those 'short' bonds on the cyclopentane, or on the alpha bonds stemming below the cyclopropane. I'll just infer methyl groups, for now.

Of course, without knowing the actual natural product, and without access to database software due to the holiday, I have no way to know if I'm barking up the right tree. Anyone care to help?


Happy Fourth of July, everyone!


Update, 7/4/12 - Commenter @azmanam wins the platinum coin for his search efforts, locating the correct intermediate from a Boger total synthesis (see below). So, in the end, I went 4 for 9 on "mystery atoms!"

Chemistry Words, with Friends

A recent discussion on Twitter brought some salient sci-comm discussion: Why aren't more chemical terms acceptable for play in the smartphone app Words with Friends?

(Not Really)
Source: Fake Science Tumblr

Unfamiliar with the game? Words, much like Scrabble, prompts players to place lettered tiles to form words on a 15 x 15 grid. The game rewards you for playing unusual letters (Q, Z, each worth 10 points) and for building words across certain labeled spaces, which confer extra points to certain letters and longer words (In fact, critics and fans both remark that WWF seems to be more like a "math game" than erudite word selection).

So, you'd think that WWF would allow submission of any legal word, right? Well, since language constantly evolves, the designers limited choices to a public-domain word list, ENABLE, containing ~173,000 words. Quite a lot, really, until you compare that to SOWPODS, the tournament Scrabble players' list, weighing in at 267,000 (and counting!).

The ENABLE list, ranging from "aa" (lava) to "zyzzyvas" (a weevil), represents scientific fields from anthropology to zoology. Large 'blocks' of terms deal with nuclear energy, geology, physics, and biology. So, what about chemistry?

I spent a few minutes trawling the list, then picking the brains of my colleagues. With this (very) minor effort, we found just a handful of terms missing: ipso, meso, fluorous, and chiron. [Words we guessed might not be there, but were, included: carbocycle, solute, solvent, catalyst, nucleophile, polydisperse, synclinal, catechol, aglycon, zincate, chiral, orbital, glycine, alkali, ketone, and bromide.]

All in all, more chemical variety than I had expected. Readers, I've obviously not covered the gamut of chemical terms, so if you find ENABLE lacking, let me know in the comments. Or, better yet, let Zynga know!