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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Molecules 2010, 15(9), 6106-6126; https://doi.org/10.3390/molecules15096106
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)
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. View Full-TextKeywords:
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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