Ring-Fused 1,4-Dihydro[1,2,4]triazin-4-yls through Photocyclization
Paulina Bartos, Victor G. Young, Piotr Kaszyński
Abstract
Halogen lamp irradiation of benzo[e][1,2,4]triazines 2[X] in CH2Cl2 solutions leads to planar ring-fused 1,4-dihydro[1,2,4]triazin-4-yl radicals 1 through a novel, potentially general, cyclization mechanism. The scope and efficiency of the method were established for unsubstituted and ortho-substituted (X = NH2, Br, NO2) phenoxy, naphthyloxy, and quinolinoxy derivatives 2[X]. The regioselectivity of 2[X] photocyclization was rationalized with DFT computational methods. Radicals 1 were characterized by spectroscopic (UV–vis, EPR), electrochemical, and XRD methods.
Topics & Concepts
ChemistryRing (chemistry)Medicinal chemistryStereochemistryCombinatorial chemistryOrganic chemistryPhotochromic and Fluorescence ChemistrySynthesis and Characterization of Heterocyclic CompoundsRadical Photochemical Reactions