Question

organic chemistry lab.

can you please find the final product based on the given 13C NMR, 1H NMR, and mass spectra.

please explain to me how to read them too. thank you!

DSpectrum BC ancar with the on

Answer 1

Proposed Structure Name: 2-methylbutyl acetate Chemical Formula: C7H1402 Exact Mass: 130.0994 d Degree of Unsaturation=C+1 - + @ 60- =7+1-7 = 1 1H NMR 1H Signal Integration Multiplicity Chemical Shift (ppm) 2.1 4.4 1.8 H marked a H marked c H marked d H marked e H marked f | H marked g singlet doublet octet doublet quintet triplet

13C NMR Chemical shift (ppm) 21 171 69 Assignment to Carbon Carbon marked a Carbon marked b Carbon marked c Carbon marked d Carbon marked e Carbon marked f Carbon marked g 34 16 26 Mass Fractions: m/z: 87 m/z: 101 m/z: 130 m/z: 43

Multiplicity Rule: The multiplicity of any peak depends on the number of neighboring protons. If a protons contain n number of neighboring protons then the splitting will be n+1. Suppose a proton contains 2 neighboring H then it will give a triplet (2+1). However sometimes the splitting changes due to germinal vicinal etc. coupling in certain cases. The double bond equivalent is 1. It contains one pi bond for C=O. The carbonyl present is for ester, which is confirmed by the peak at 171 ppm in 13C NMR. One peak at 4.4 ppm in 1H NMR for 2H shows that one CH2 group is attached to the ester oxygen. That is showing a doublet that means there are only one neighboring H to this CH2. So, the d' have only one H. A peak at 2.1 in 1HNMR shows presence of acetyl CH3. Peaks at 1.4 ppm (quintet, 2H) and 0.8 (triplet, 3H) shows the presence of ethyl group that is attached to a carbon which contains one H. The mass fragments as shown above also corroborates the structure.