Organic Chemistry
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Shown below is the mass spectrum of butan-2-ol. Identify the m/z of the fragments generated from one dehydration and two α-cleavage fragmentations.
Show three ways the given tertiary amine can undergo α-cleavage. Indicate the m/z that corresponds to each fragment.
Suggest the molecular formula and structure that gave the base peak at m/z 31.
For the following compound, draw the structure of any one major fragment expected to appear in its mass spectrum.
For the given compound, draw the structure of any one major fragment expected to appear in its mass spectrum.
For the given molecule, draw the structure of any one major fragment expected to appear in its mass spectrum.
Looking at the given spectra, explain why the molecular ion peak is prominent in the mass spectrum of benzyl fluoride while it is almost absent in the mass spectrum of benzyl bromide.
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In the following mass spectrum, identify the peaks that represent the α-cleavage of heptan-3-one.
The mass spectra of 1-methoxybutane and 1-ethoxypropane are shown below. Identify which spectrum corresponds to each compound
Provide the major fragments expected in the mass spectrum of 2-ethoxy-2-methylpropane.
What peak can be used to distinguish the mass spectrum of 2-methylpentane from n-hexane and 3-methylpentane?
The mass spectrum of unbranched primary alcohols often shows a peak at M–46. Determine the fragment/s lost that caused this peak.
An unknown compound contains strong peaks at m/z = 45 and 87 in its mass spectrum. Which of the compounds below corresponds to the mass spectrum?
The mass spectrum of 3-methyl-1-butanol is given below. Provide the mechanism of the formation of the peak at m/z = 70.
Predict the most intense peaks that could be observed in the mass spectrum of 2-methylpropan-2-ol.
The mass spectrum of 2-methylpentan-3-ol has peaks at m/z 73, 59, and 43. Draw structures for the fragments that give rise to these peaks in the mass spectrum of 2-methylpentan-3-ol.
A graduate student was studying nucleophilic addition reactions of ketones. To start with, she added ethyl iodide to a flask containing anhydrous ether and chunks of magnesium metal. The result was an exothermic reaction and the ether in the flask started boiling. After the ether stopped boiling, she added 2-butanone to the flask and the ether started boiling again, indicating another exothermic reaction. After the reaction mixture cooled down, she added dilute acid to the mixture and separated the aqueous and ether layers. She evaporated the ether layer and purified the obtained product. GC-MS analysis of the purified product shows the presence of a major product with a few impurities. Explain why the molecular ion peak is not visible in the spectrum and determine which ions are likely to be present in the spectrum.
The mass spectrum of ethylbenzene has a base peak at m/z 91. Identify the fragmentations that yield the ions responsible for the peaks at m/z 106, 91, and 77 in its mass spectrum.
Ethers are a bit difficult to differentiate using IR spectra alone. However, they form distinctive fragments in their mass spectra. Consider the following two compounds:
Both compounds give three distinct peaks at m/z 73, 59, and 45. One compound gives a base peak at m/z 59 while the other gives a base peak at m/z 45. Identify each compound based on its base peak and draw a fragmentation that accounts for these base peaks.
Predict the most intense peaks that could be observed in the mass spectrum of 2,3-dimethylbutane.
Predict the most intense peaks that could be observed in the mass spectrum of (E)-4-methylpent-2-ene.
A very intense base peak at m/z 44 appears in the mass spectrum of di-isopropylamine. Identify the correct cleavage diagram that accounts for the formation of the intense base peak at m/z 44 in the mass spectrum of diisopropyl amine. Also state reason for a relatively small molecular ion peak visible in the spectrum at m/z 101.
Consider the following compounds and the given mass spectral data:
a. M+ doublet at m/z 156 and 158.b. Base peak at m/z 91.c. A strong peak at m/z 41.d. Base peak at m/z 43.
Match each structure with its characteristic ions from the given data.
Which fragments/ions give rise to the peaks at m/z 87, 57, and 41 in the mass spectrum of diisobutyl ether?