Molecules 2010, 15(9), 6106-6126; https://doi.org/10.3390/molecules15096106
Heterocyclic Analogues of Xanthone and Xanthione. 1H-Pyrano[2,3-c:6,5-c]dipyrazol-4(7H)-ones and Thiones: Synthesis and NMR Data
Department of Drug and Natural Product Synthesis, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
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Received: 28 July 2010 / Revised: 27 August 2010 / Accepted: 31 August 2010 / Published: 1 September 2010
(This article belongs to the Special Issue Advances in Heterocyclic Chemistry)
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Abstract
The synthesis of the title compounds is described. Reaction of 1-substituted 2-pyrazolin-5-ones with 5-chloro-1-phenyl-1H-pyrazole-4-carbonyl chloride or 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbonyl chloride, respectively, using calcium hydroxide in refluxing 1,4-dioxane gave the corresponding 4-heteroaroylpyrazol-5-ols, which were cyclized into 1H-pyrano[2,3-c:6,5-c]dipyrazol-4(7H)-ones by treatment with K2CO3/DMF. The latter were converted into the corresponding thiones upon reaction with Lawesson’s reagent. Detailed NMR spectroscopic investigations (1H, 13C, 15N) of the ring systems and their precursors are presented.Keywords:
pyrazolones; 1H-pyrano[2,3-c:6,5-c]dipyrazol-4(7H)-ones; cyclization; Lawesson’s reagent; NMR spectroscopy
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Datterl, B.; Tröstner, N.; Kucharski, D.; Holzer, W. Heterocyclic Analogues of Xanthone and Xanthione. 1H-Pyrano[2,3-c:6,5-c]dipyrazol-4(7H)-ones and Thiones: Synthesis and NMR Data. Molecules 2010, 15, 6106-6126.
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