Browsing by Author "Ganesan, Kilivelu"

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Unusual Anisotropic Effects from 1,3-Dipolar Cycloadducts of 4-Azidomethyl Coumarins
(2010-01-01)
Kusanur, Raviraj A.
;
Kulkarni, Manohar V.
;
Kulkarni, Geetha M.
;
Nayak, Susanta K.
;
Row, Tayur N. Guru
4-Bromomethylcoumarins (1) reacted with sodium azide in aqueous acetone to give 4-azidomethyl-coumarins (2), which underwent 1,3-dipolar cycloaddition with acetylenic dipolarophiles to give triazoles (3). These triazoles (3) have been found to exhibit interesting variations in the chemical shifts of C(3)-H and C(4)-methylene protons. Protonation studies indicate that the shielding effect of the C(3)-H of coumarin is due to pi-electrons of the triazole ring, further supported by diffraction and computational studies.