TY - JOUR
T1 - Synthesis of 5,7-dihydrodibenzo[b,f][1,7]naphthyridine-6,12-dione, an unexpected isolate from Isatis tintoria
AU - Riepl, Herbert M.
AU - Kellermann, Melanie
PY - 2009/4
Y1 - 2009/4
N2 - The dye plant Isatis tinctoria yields a number of heterocyclic compounds with interesting anti-inflammatory and cytotoxic properties, formed mainly in an unknown manner by post-harvest treatment. A synthesis of the incidently isolated 5,7-dihydrodibenzo[b,f][1,7]naphthyridine-6,12-dione (4a) is presented. Starting from different 1,2-diarylhydrazines, adducts 11 with acetylenedicarboxylates (=but-2-ynedioates) are thermally treated (Scheme). In a Fischer-type rearrangement, 3-(arylamino)quinolinecarboxylic acids 9 are obtained, which can be cyclized under Friedel-Crafts conditions to yield a number of analoga 4 of the title compound.
AB - The dye plant Isatis tinctoria yields a number of heterocyclic compounds with interesting anti-inflammatory and cytotoxic properties, formed mainly in an unknown manner by post-harvest treatment. A synthesis of the incidently isolated 5,7-dihydrodibenzo[b,f][1,7]naphthyridine-6,12-dione (4a) is presented. Starting from different 1,2-diarylhydrazines, adducts 11 with acetylenedicarboxylates (=but-2-ynedioates) are thermally treated (Scheme). In a Fischer-type rearrangement, 3-(arylamino)quinolinecarboxylic acids 9 are obtained, which can be cyclized under Friedel-Crafts conditions to yield a number of analoga 4 of the title compound.
UR - http://www.scopus.com/inward/record.url?scp=65749085049&partnerID=8YFLogxK
U2 - 10.1002/hlca.200800337
DO - 10.1002/hlca.200800337
M3 - Article
AN - SCOPUS:65749085049
SN - 0018-019X
VL - 92
SP - 668
EP - 676
JO - Helvetica Chimica Acta
JF - Helvetica Chimica Acta
IS - 4
ER -