波谱分析课件第6章 节 综合解析再编2.pptVIP

第六章 波谱综合解析;常规谱;(B);;;(C);(C);5;5;5;5;(D);;;;;;13C satellites of intense proton peaks, especially methyl groups. If we trace parallel to the proton axis (F2) at about 23 pprn on the carbon axis (Fl), we find a cross peak at about 0.93 pprn (proton), which is real. On either side, we find two cross peaks that do not line up (correlate) with any protons in F2. These are 13C satellites and should be ignored. The other methyl carbon resonance shows the same phenomenon; the satellite peaks are marked with arrows in the figure. ;;A (6H,2.5ppm,s);b;b;b;1.某化合物A，分子式C13H18O2，其谱图如下，请确定其结构。;;H H COSY spectrum;;;HMQC spectrum;;2.某化合物B，分子式C8H6O3，其谱图如下，请确定其结构。;1H NMR in CDCl3;;HMQC spectrum;HMBC spectrum(C－H远程偶合);;Interpretation of HMBCs requires a degree of flexibility because we do not always find what we expect to find. In particular, depending on the hybridization of carbon and other factors, some of the two-bond correlations (2JCH) or three-bond (3JCH) correlations are occasionally absent. To add to the confusion, infrequently we find four-bond (4JCH) correlations! The variations in correlations that we find are due to the variations in the magnitude of 2JCH, 3JCH, and 4JCH coupling constants. ;3.某化合物C，分子式C8H14O，其谱图如下，请确定其结构。;;;;HMQC spectrum;HMBC spectrum(C－H远程偶合);