May 6, 2008
An integral part of an elucidation is to recognize and associate an NMR spectral pattern to a structure or fragment. A challenging elucidation can be simplified by being aware of as many as possible NMR patterns. One example is morpholine; it typically shows a distinct NMR pattern.
A portion of the 1H-13C DEPT-HSQC spectrum for 4-phenylmorpholine is shown below. The 2 negative correlations on the DEPT-HSQC experiment indicate the presence of CH2 groups. In addition, the carbon at 67 ppm must be closer to an electron-withdrawing group such as an oxygen atom. The attached 1H NMR also shows the resonances having approximately equal integrals and tilted towards each other.