期刊
JOURNAL OF FLUORINE CHEMISTRY
卷 131, 期 10, 页码 1013-1024出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.jfluchem.2010.07.007
关键词
Pyrazolones; Acylation; Ring closure; Chromeno[2,3-c]pyrazol-4(1H)-one; NMR ((1)H, (13)C, (15)N, (19)F)
A straightforward, two-step synthesis of fluoro substituted chromeno[2,3-c]pyrazol- and [1] benzothieno[2',3':5,6]pyrano[2,3-c]pyrazol-4(1H)-ones, respectively, is presented. Hence, treatment of 1-substituted or 1,3-disubstituted 2-pyrazolin-5-ones with fluoro substituted 2-fluorobenzoyl chlorides or 3-chloro-6-fluoro-1-benzothiophene-2-carbonyl chloride using calcium hydroxide in refluxing 1,4-dioxane gave the corresponding 4-aroylpyrazol-5-ols, which were cyclized into the fused ring systems. 5-Fluorochromeno[2,3-c]Pyrazol-4(1H)-one was obtained upon treatment of the 1-(4-methoxybenzyl) protected congener with trifluoroacetic acid. Treatment of 5-fluorochromeno[2,3-c]pyrazol-4(1H)-ones with methylhydrazine afforded novel tetracyclic ring systems such as 2-methyl-7-phenyl-2,7-dihydropyrazolo[4',3':5,6]pyrano[4,3,2-cd]indazole. Detailed NMR spectroscopic investigations ((1)H, (13)C, (15)N, (19)F) with the obtained compounds were undertaken. (C) 2010 Elsevier B.V. All rights reserved.
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