One-pot access to pyridocoumarins via Povarov-hydrogen transfer cascade under auto-tandem catalysis of iodine in aqueous micelles
作者:Nemai C. Ganguly、Sumanta Chandra
DOI:10.1016/j.tetlet.2014.01.078
日期:2014.2
A cascade of inverse electron demand Diels-Alder reaction of 6-aminocoumarin-derived aldimines with an excess of styrene and oxidative aromatization of the formal Povarov adducts under autotandem iodine catalysis in aqueous micellar conditions provides direct access to a small library of substituted pyridine annulated coumarins in good to acceptable yields (12 examples). The unusual formation of linearly annulated pyridocoumarins under essentially neutral conditions is a remarkable feature of the protocol. (C) 2014 Elsevier Ltd. All rights reserved.
Synthesis and antimicrobial activity of some methyl-2-[<i>N</i>-coumarin-6â²-yl]-3-oxo-2,3-dihydro-1<i>H</i>-isoindolone-5-carboxylates
作者:Aabid Ali Mir、Vinata V. Mulwad、G. K. Trivedi
DOI:10.1002/jhet.274
日期:——
N-substituted furylmethylimines are prepared by condensing 6-aminocoumarins with furfural, these on sodium borohydride reduction afford N-[coumarin-6′-yl]-2-furylamines. Intramolecular [4+2] cycloaddition of these amines with maleic anhydride results into 3-[N-coumarin-6′-yl]-4-oxo-10-oxa-3-azatricyclo[5.2.1.01.5]dec-8-ene-6-carboxylic acids . The [4+2] cycloadducts on p-toluene sulphonic acid treatment followed