1240508-59-1Relevant articles and documents
Heterocyclic analogues of xanthone and xanthione. 1H-pyrano[2,3-c:6,5-c] dipyrazol-4(7H)-ones and thiones: Synthesis and NMR data
Datterl, Barbara,Troestner, Nicole,Kucharski, Dorota,Holzer, Wolfgang
experimental part, p. 6106 - 6126 (2010/11/04)
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 K 2CO3/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.