Indian Institute of Integrative Medicine

Novel C-2 homo-pyranose nucleosides can be synthesized by regioselective glycoconjugation of C-2 acetoxymethyl glycals with nucleobases in the presence of a catalytic amount of a Lewis acid. The reaction proceeded via the formation of exo-Ferrier allylic cation as an intermediate and the site selectivity is controlled on the basis of HSAB principle.

The Rosellinia sanctae-cruciana extract was subjected to detailed liquid chromatography tandem mass spectrometry studies. A total of 38 peaks were annotated to m/z 508.26, m/z 510.28, m/z 524.26, m/z 526.28, m/z 540.26, m/z 542.27, and m/z 584.28 [M + H]⁺. The accurate mass, mutually supported UV/vis spectra, and database search identified these compounds as cytochalasins. Systematic dereplication helped identify a peak at m/z 540.26 [M + H]⁺ as the new compound. Further, the identified compound was purified by high-performance liquid chromatography and characterized by 2D NMR to be 19,20-epoxycytochalasin N1, a new optical isomer of 19,20-epoxycytochalasin-N. It exhibited substantial cytotoxicity with IC₅₀ values ranging from 1.34 to 19.02 μM. This study shows a fast approach for dereplicating and identifying novel cytochalasin metabolites in crude extracts.

A Ni-catalyzed direct access to various pyrano cis-fused dihydro benzofurans and indoles from unsaturated enopyranoses and o-iodo phenols/anilines is developed. The domino synthesis of pyrano C2-C1 and C3-C2 cis-fused heteroarynes were achieved both from glycals and pseudo glycals in which heteroatoms are linked at C2 and C3 positions, respectively, with excellent chemo-selectivity.