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2005
Fused pyridine derivatives
Fused pyridine derivatives
R 0450
Organic Azides in Heterocyclic Synthesis. Part 33. Synthesis and Ring Closure
of Pyrido[3,2,1-jk]carbazol-6-ones. — Pyridocarbazolones (III), (IX), and
28- 158 Reactions
(XV) possessing two reactive positions, i.e. the hydroxy group at C-4 and the CH-acidic
proton at C-5, are subjected to acetylation, tosylation as well as to nucleophilic exchange of the hydroxy groups. Cyclocondensation methods are adopted for these compounds improving their syntheses. In these reactions the first step consists of a condensation reaction, followed by thermolysis, cf. (I)→(IX). This reaction can also be carried
out in one step by heating the carbazole with the malonate in diphenyl ether, cf.
(I)→(III), making the work-up easier and the purity of the products better. The synthesis of the desired 5-alkylated azide derivatives from the corresponding precursors, e.g.
(VI), is impossible. However, a new one-pot synthesis provides the targets, e.g. (VII),
in low to moderate yields, but with excellent purity. On cyclization, (XII) affords the
highly fused indolopyridocarbazolone (XIII), a hitherto unknown heterocyclic system.
— (DANG, H. V.; KNOBLOCH, B.; HABIB, N. S.; KAPPE, T.; STADLBAUER*, W.;
J. Heterocycl. Chem. 42 (2005) 1, 85-91; Dep. Chem., Karl-Franzens-Univ.,
A-8010 Graz, Austria; Eng.) — H. Hoennerscheid
2005
Fused pyridine derivatives
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