Molecular structure and reactions of 1,1'-bi(acenaphthen-1-ylidene)-2,2'-dione

The molecular structure of 1,1'-bi(acenaphthen-1-ylidene)-2,2'-dione 1, a potential building-block for the synthesis of fullerene fragments, has been investigated by X-ray crystallography and semi-empirical (AM1 and PM3) calculations. There is a good agreement between the calculated and crystal structure which is essentially planar and has E-configuration. In the solid state, molecules of 1 pack in an interesting manner as corrugated sheets sustained by a network of C-H···O hydrogen bonds and resulting in the formation of tetrameric loops. While steric factors limit the reactivity of the carbonyl groups in 1, the ene double bond of the ene-dione moiety present in it exhibits propensity toward [4 + 2]-cycloadditions to furnish novel and highly compressed polycycles 8-10

Chiral switches of chloroquine and hydroxychloroquine: potential drugs to treat COVID-19

Therapeutic options in response to the COVID-19 pandemic are urgently needed. A keyword in these worldwide effortsis ‘repurposing’ – the development of approved antiviral drugs as candidates for COVID-19. Chloroquine (CQ) and its hydroxyl analog hydroxychloroquine (HCQ) are showing preliminary inhibitory effects against COVID-19 and apparent efficacy in clinical studies. We propose a variant of the repurposing strategy: developing single enantiomers of these old racemic drugs. We call for urgently pursuing the chiral switches of HCQ and/or CQ for the treatment of COVID-19

Measures of pyramidalization

This article reviews common definitions of pyramidalization. An appraisal of the quantification of pyramidalization follows, and the formulation of a new measure of pyramidalization. The versatility of the new measure is tested using correlation with some molecular properties