Ethyl 3??and 5??Triflyloxy??1H??pyrazole??4??carboxylates in the Synthesis of Condensed Pyrazoles by Pd??Catalysed Cross??Coupling Reactions

…, G Vilkauskaitė, A Šačkus, W Holzer

Index: Arbaciauskiene, Egle; Vilkauskaite, Gyte; Sackus, Algirdas; Holzer, Wolfgang European Journal of Organic Chemistry, 2011 , # 10 p. 1880 - 1890

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Citation Number: 6

Abstract

Abstract The easily obtainable title compounds ethyl 5-and 3-triflyloxy-1H-pyrazole-4- carboxylates (2 and 5) have been used as precursors in Sonogashira-type cross-coupling reactions with various alkynes to obtain the corresponding 5-and 3-alkynyl-4- (ethoxycarbonyl) pyrazoles 3 and 6. Cyclization of the latter ortho-difunctional synthons afforded different condensed pyrazoles such as pyrano [4, 3-c] pyrazol-4 (1H)-ones and-4 ...