N. Kleizienė, Eglė Arbačiauskienė, W. Holzer
Nov 5, 2009
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Influential Citations
3
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Molbank
Abstract
Abstract: The title compound was prepared by treatment of 4-bromo-1-phenyl-1 H -pyrazol-3-ol with sodium hydride/methyl iodide in good yield. Detailed spectroscopic data ( 1 H NMR, 13 C NMR, 15 N NMR, IR, MS) are presented. Keywords: pyrazole; 1 H -pyrazol-3-ol; methylation; NMR Bromo(hetero)arenes are valuable starting materials for further functionalization, for instance via metalation reactions (halogen-metal exchange) [1] or transition-metal-catalyzed cross coupling reactions [2–4]. With an OH- or OR function in ortho -position to the bromo atom, such (hetero)arenes can be considered as potential precursors for condensed systems involving a ring-oxygen atom (condensed furans, pyranes) [5]. However, for some of the above mentioned functionalization reactions, free hydroxy groups are unfavourable, for instance in metalation reactions [6] or in Suzuki-type cross couplings [7]. In such cases, the OH group has to be masked. In this regard, a possible option is to transform the OH into the very stable OMe group. The O–Me bond then can be cleaved in the course of the cyclization reaction into the