Stadlbauer W., Täubl A. E., Knobloch B.,
Proceedings of the Electronic Conference on Heterocyclic Chemistry '98 (ECHET98), H. S.
Rzepa and C. O. Kappe, (Eds), Imperial College Press, 1998; CD-ROM, ISBN
981-02-3594-1, paper 18.
Abstract: In this communication some new synthetic pathways to pharmacologically interesting target
molecules are described. Carbo- and heterocyclic 1,3-dioxo compounds 1
having as basic ring system a pyridine, pyrane, quinoline, coumarin or phenalenone
give the reactive 1-chloro-3-oxo intermediates 2, which can be alkylated
with CH-acidic compounds such as malonates if the substituent R1 has
electron acceptor properties . Alkyl derivatives 3 have been shown
in some cases (e.g. as 4-alkyl-2-pyridones) to possess antiviral activity .
The thermolytic degradation of ethyl malonates of type 3 gives the ethyl
acetates 4. With the 2-quinolone ring system this class of compounds
shows manifold pharmacological activities.
Methyl malonates 3 having
as substituent R1 a nitro group form under thermolytic conditions
by loss of carbon dioxide and methanol isoxazoles of type 7.
The thermolysis reactions to 4 and 7 have been studied by
differential scanning calorimetry (DSC).
The Wittig- or Grignard reaction of 2,2-disubstituted 1,3-dicarbonyl carbo- or heterocycles
5 with alkyl-triphenylphosphonium halides leads to 1-alkylidene-3-oxo compounds
6. This compound class was recently found to show antiviral activities .
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