Synthesis, reaction, theoretical calculation, NMR study and X-ray crystal structure of 1-substituted and 1-unsubstituted 1H-pyrazol-5(2H)-ones
作者:Orazio A. Attanasi、Lucia De Crescentini、Paolino Filippone、Elisabetta Foresti、Roberta Galezzi、Ion Ghiviriga、Alan R. Katritzky
DOI:10.1016/s0040-4020(97)00217-2
日期:1997.4
studied by molecular mechanics calculations, as well as deuterium induced shifts (DIS) on 13C chemical shifts, and tentative conclusion was drawn about their tautomerism and conformations. X-Ray crystal structure determinations of 1-(aminocarbonyl)-3-methyl-4-methoxy-1H-pyrazol-5(2H)-one 4e and 3-methyl-4-methoxy-1H-pyrazol-5(2H)-one 5a demonstrated that both molecules exist in the crystal exclusively
通过共轭偶氮烯烃与醇,硫醇和酚的反应已经制备了1-取代的4-烷氧基-,4-烷硫基和4-芳氧基-1 H-吡唑-5(2 H)-。在某些情况下,分离出中间,而在其他情况下,则一步一步获得产物。通过在回流下甲醇裂解相应的1-取代的衍生物来制备1-未取代的4-烷氧基-,4-烷硫基-和4-芳氧基-1 H-吡唑-5(2 H)-。通过分子力学计算研究了其中一些化合物,以及13位的氘诱导的位移(DIS)。C化学位移,并就其互变异构和构象作了初步结论。1-(氨基羰基)-3-甲基-4-甲氧基-1 H-吡唑-5(2 H)-one 4e和3-甲基-4-甲氧基-1 H-吡唑-5()的X射线晶体结构测定2 H)-1 5a证明两个分子仅以HN-CO互变异构形式存在于晶体中。一些吡唑啉酮和羟基吡唑中先前报道的一些结构分配已得到纠正。