Friday, November 01, 2013

OK, One Last More...

Adamantane (tricyclo[,7]decane) is a cycloalkane and also the simplest diamondoid. Check out Wikipedia. Cyclohexane isn't flat: its thermodymanically favorably configuration "chair" (it looks like a beach chair) four such fit together to make a stunningly symmetrically three-dimensionally configuration. One thing we certainly know is that oddly stable, totally hydrocarbon compound can have medical significance.

An aminoadamantane is a drug; there are other derived drugs.What is going on here??


  1. Not 100% sure what you mean, but - -

    -the structure can have no conformational isomers because bond rotation is impossible. So one would expect its binding affinities to be more specific than other similar weight compounds. (But many, many other fused ring structures are like that. There are gazillions of fused ring, biologically active compounds out there. ) In general, the more structurally rigid the better, as pharmacophores go. It helps to keep them from binding non-specifically and getting washed out or causing other mayhem somewhere else in the system.

    - The high symmetry means that there is a great deal of degeneracy of the bound state. So, even though enthalpically, the energetics of binding are going to be pretty mediocre (all it's got going for it is some weak Vander Waals interactions) statistically the bound state is (I think) 12-fold degenerate or so for adamantane. So practically speaking, the binding equilibrium will probably be observed to be much more favorable than one might naively guess in comparison to other similar weight compounds. (But really, who would do that? This is not a subject that you can easily generalize about in that sort of way. )

    - The symmetry probably also helps with binding specificity, because relative to the surface area, it is only presenting one small and highly specific binding face over and over, if you see what I mean. It is basically a highly symmetrical multidentate ligand.

    That is how I would think about it, anyway. Since you are a math guy, that is probably not quite what you were looking for.

    1. Nice. Better than I had put it to myself and had despaired of sketching my foggy thoughts on the subject.

  2. Wabulon, if you don't stop griping about quitting and get blogging, you're fired!

    1. Admitted. You're right. OK. G'bye.


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