Divneet Kaur’s favorite structure is:

methyl α-(5,6-dimethoxycarbonyl-2,3-dimethoxyazepin-7-ylidene)-α-[5-methoxycarbonyl-2,3-dimethoxypyrid-6-yl)acetate


Source: Eswaran et al, J. Het. Chem., 1996, 33(4), 1333


The compound is also called as ‘Viswamayene’. The crystal is one of its kind of a small organic molecule with M.Wt= 534. It is a highly unusual compound in its formation and structure and is formed from a ‘long lived’ singlet nitrene species generated from a tetra substituted aryl azide. The compound is formed via a concomitant ring expansion and ring extrusion reaction, thereby leading to a formation of a pyridyl carbene species from a nitrene. The unusual and un-precedented reaction finds no alternative in literature and forms the basis of another set of rather similar unusual compounds reported from my laboratory which is also a part of my Ph.D thesis work. I feel, that X-ray played a crucial role in determining the exact structure of the compound as NMR techniques were not too sophisticated at that time. The compound gives a rare evidence for the formation of a pyridyl group from a benzene molecule by a series of rearrangements. I, thus feel that this highly unusual molecule has no precedence in literature and hence should be highlighted and recognised for its rare mechanism of formation. —Divneet Kaur

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