title: Heterocyclic analogues of xanthone and xanthione. 1H-pyrano[2,3-c:6,5-c]dipyrazol-4(7H)-ones and thiones: synthesis and NMR data.
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.
authors.affiliation: Department of Drug and Natural Product Synthesis, Faculty of Life Sciences, University of Vienna, Vienna, Austria. barbara.datterl@univie.ac.at
authors.forename: Barbara
authors.initials: B
authors.lastname: Datterl
authors.forename: Nicole
authors.initials: N
authors.lastname: Tröstner
authors.forename: Dorota
authors.initials: D
authors.lastname: Kucharski
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Holzer
mesh_terms: D004146:Dioxanes; D006571:Heterocyclic Compounds / Q000138:chemical synthesis*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D011720:Pyrazoles; D013871:Thiones / Q000138:chemical synthesis / Q000737:chemistry*; D044004:Xanthones / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D004146:Dioxanes; D006571:Heterocyclic Compounds; D011720:Pyrazoles; D013871:Thiones; D044004:Xanthones; C009689:xanthone; C025223:1,4-dioxane