Heterocyclic analogues of xanthone and xanthione. 1H-pyrano[2,3-c:6,5-c]dipyrazol-4(7H)-ones and thiones: synthesis and NMR data.
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.
Datterl
Barbara
B
Department of Drug and Natural Product Synthesis, Faculty of Life Sciences, University of Vienna, Vienna, Austria. barbara.datterl@univie.ac.at
Tröstner
Nicole
N
Kucharski
Dorota
D
Holzer
Wolfgang
W
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*
D004146:Dioxanes; D006571:Heterocyclic Compounds; D011720:Pyrazoles; D013871:Thiones; D044004:Xanthones; C009689:xanthone; C025223:1,4-dioxane