synthesis of mono- and dibromo-derivatives of 1-phenylpyrazol-3-ol合成mono - dibromo-derivatives 1-phenylpyrazol-3-ol.pdfVIP

M551 Synthesis of Mono and DibromoDerivatives of 1-Phenylpyraz... Molbank 2007, M551 /molbank/ Synthesis of Mono and DibromoDerivatives of 1-Phenylpyrazol-3-ol a a a b Eglė edzelskytė , Vytas Martynaitis , Algirdas Šačkus , Gernot A. Eller and Wolfgang Holzer b, * a Institute of Synthetic Chemistry, Kaunas University of Technology, Radvilėnų pl. 19, LT50254 Kaunas Lithuania b Department of Drug and Natural Product Synthesis, Faculty of Life Sciences, University of Vienna Althanstrasse 14, A1090 Vienna, Austria * Author to whom correspondence should be addressed. Tel: +431427755623; Email: wolfgang.holzer@univie.ac.at Received: 30 January 2007 / Accepted: 15 February 2007 / Published: 30 May 2007 Keywords: 1phenylpyrazol3ol, bromination, Oacetylation, NMR spectroscopy Abstract: Dependent on the reaction conditions, 1phenylpyrazol3ol and bromine give either 4bromo 1phenylpyrazol3ol (2a) or 4bromo1(4bromophenyl)pyrazol3ol (2b). Treatment of 2a or 2b with refluxing acetic anhydride leads to the corresponding Oacetyl derivatives 3a and 3b, respectively. 1 13 15 Detailed spectroscopic data ( H NMR, C NMR, N NMR, MS, IR) for 2b, 3a and 3b are presented. In the course of investigations regarding Pdcatalyzed cross coupling reactions with halopyrazoles [1], we prepared 4bromo1phenylpyrazol3ol (2a) via reaction of 1phenylpyrazol3ol (1) with one equi