Question

Match the following compound to spectrum shown below:

Which compound below best matches the following spectrum? All molecules are C9HioC2O. a) b) CI C c) CI Cl d) CI e) CI ci ab) CI CI PPM

How would you solve this in a step-by-step fashion? I'm really confused on how to solve these, so if you could show me a systematic way of doing this, using this problem as an example, that would be really helpful!

Answer 1

First, check the peak as doublets of doublet at ~5.5 ppm that belongs to alkenic H. Hence, compond must have atleast one alkenic proton. Now, compound (c), and (ab) are rulled out as they donot have alkenic hydrogen.
Compound must have three CH3 groups and among them two CH3 must be attached to a CH unit (because signals for two CH3 are doublet in the region 1.5-2.5 ppm). So, compound (d) is cancelled for selection.
Now, there are choices between (a), (b) and (d). Compound (d) should give a doublet for 2H (for CH2 attached to Cl which is not visible in data. For cpompound (a), there must be a triplet for CH3 and quartet for CH2 group for -CH2CH3 group in ether linkage part which are absent.
So, the data belongs to compound (b).