Synthesis of Pyrano[4,3-<i>c</i>]pyrazol-4(1<i>H</i>)-ones and -4(2<i>H</i>)-ones from Dehydroacetic Acid. Homo- and Heteronuclear Selective NOE Measurements for Unambiguous Structure Assignment
作者:Albert Cantos、Pedro de March、Marcial Moreno-Mañas、Anna Pla、Francisco Sanchez-Ferrando、Albert Virgili
DOI:10.1246/bcsj.60.4425
日期:1987.12
Cyclization of dehydroacetic acid N-substituted hydrazones furnished 1-substituted 3,6-dimethylpyrano[4,3-c]pyrazol-4(1H)-ones, together with varying amounts of N,N′-disubstituted 5-hydroxy-3-methyl-4-(3-methyl-1H-pyrazol-5-yl)-1H-pyrazoles. The same pyranopyrazolones were obtained regioselectively without side reactions from N-alkylhydrazines and 4-chloro-3-(1-chlorovinyl)-6-methyl-2H-pyran-2-one
作者:James W. Pavlik、Vuthichai Ervithayasuporn、Supawan Tantayanon
DOI:10.1002/jhet.562
日期:2011.5
AbstractSynthetic methods have been developed to prepare pyrano[2,3‐c]pyrazoles with various substituents at ring positions 1, 3, and 6. The 1H‐ and 13C‐NMR properties of these products and their precursors are presented and discussed. J. Heterocyclic Chem., (2011).