Archive for October, 2022

Derek Lowe asks “What’s a Journal For?” – Knowledge graphs?

Friday, October 21st, 2022

What’s a Journal For? This debate has been raging ever since preprint servers were introduced as far back as 1991! Indeed, during my recent submission of a journal article, one of the questions asked was whether the article was already deposited in such a preprint server (in a positive sense, and not one excluding further submission progress). Since my previous comment on this theme was made more than three years ago, I thought I might update it.


Nitroaryls- A less-toxic alternative reagent for ozonolysis: modelling the final step to form carbonyls.

Saturday, October 8th, 2022

Sometimes you come across a reaction which is so simple in concept that you wonder why it took so long to be accomplished in practice. In this case, replacing toxic ozone O3 as used to fragment an alkene into two carbonyl compounds (“ozonolysis”) by a relatively non-toxic simple nitro-group based reagent, ArNO2 in which the central atom of ozone is substituted by an N-aryl group. As reported by Derek Lowe, two groups have published[1], [2] details of such a reaction (Ar = 4-cyano or 3-CF3,5-NO2). But there are (at least) two tricks; the first is to use photo-excitation using purple LEDs (390nm light) to activate the nitro group. The second is to establish the best aryl substituents to use for achieving maximum yields of the carbonyl compounds and the best conditions for achieving the cyclo-reversion reaction, shown below as TS1. That step requires heating the cyclo-adduct up to ~80° in (aqueous) acetonitrile for anywhere between 1-48 hours. Here I take a computational look at that last step, the premise being that if such a model is available for this mechanism, it could in principle be used to optimise the conditions for the process.



  1. D.E. Wise, E.S. Gogarnoiu, A.D. Duke, J.M. Paolillo, T.L. Vacala, W.A. Hussain, and M. Parasram, "Photoinduced Oxygen Transfer Using Nitroarenes for the Anaerobic Cleavage of Alkenes", Journal of the American Chemical Society, vol. 144, pp. 15437-15442, 2022.
  2. A. Ruffoni, C. Hampton, M. Simonetti, and D. Leonori, "Photoexcited nitroarenes for the oxidative cleavage of alkenes", Nature, vol. 610, pp. 81-86, 2022.