UCF - ORGANIC CHEMISTRY 2 - PROF. GERASIMOVA UCF PROF. GERASIMOVA EXAM REVIEW 1.

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1 UCF PROF. GERASIMOVA EXAM REVIEW 1 1

2 PRACTICE: Determine the index of hydrogen deficiency (degrees of unsaturation) for the following molecule. Antipsychotic - Haloperidol = C 21 H 23 NO 2 ClF PRACTICE: Which of the following is primarily obtained from IR spectroscopy: A) Arrangement of C and H atoms in compound B) Molecular weight of compound C) Conjugated π-system D) Functional groups present in compound E) All of these PRACTICE: Which C=O stretch will occur at the highest frequency (cm 1 ) in the IR spectrum? 2

3 PRACTICE: Interpret the following infrared spectra and circle the corresponding structure below. Label two peaks present on the spectra with the stretch observed. 3

4 PRACTICE: Match the following structures with the IR spectra shown below. 4

5 PRACTICE: Circle the molecule within each given set that most likely produces the given Infrared (IR) spectrum. PRACTICE: All of the following molecules contain a carbon-carbon double bond functional group. However, not all carbon-carbon double bonds are detected by infrared (IR) spectroscopy. CIRCLE those molecules that CANNOT be seen by an IR. 5

6 PRACTICE: The most abundant ion (tallest peak) in MS is called: a) molecular ion peak b) base peak c) fragment peak d) molar peak e) molecular peak PRACTICE: Which compound below is expected to show an odd molecular ion in the mass spectrum and two IR signals between 3300 and 3500 cm -1? a) H 2 NCH 2 CH 2 CH 2 CH 2 CH 2 CH 2 NH 2 b) Diethylamine c) Ethylamine d) All of the above e) None of the above 6

7 PRACTICE: How many different 1 H NMR signals are expected for the compound below? 7

8 PRACTICE: How many 1 H NMR signals would cis- 1,2-dichlorocyclopropane give? PRACTICE: How many chemically distinct 1 H NMR signals are there in the following compound? PRACTICE: How many 1 H NMR signals would trans- 1,2-dichlorocyclopropane give? 8

9 PRACTICE: How many different signals would you see in the proton NMR For the following compound? (Assume that you can see them all). PRACTICE: For the following compound how many different signals would you see in the proton NMR? (Assume that you can see them all) 9

10 PRACTICE: Predict chemical shifts for all of the protons in the molecule below. 10

11 PRACTICE: In the 1 H NMR spectrum of 1-fluorobutane, the most deshielded hydrogrens are those bound to PRACTICE: The 1 H NMR signal for which of the indicated protons occurs farthest downfield? 11

12 PRACTICE: Predict the splitting pattern you would observe for the proton at C1 of 2,3-dimethyl-2- phenylbutane. 12

13 PRACTICE: Predict the 1 H shifts and integrations for tert-butyl methyl ether. 13

14 PRACTICE: How would you distinguish between these compounds via 1 H NMR? PRACTICE: Which one of the following best represents the predicted approximate chemical shift and coupling for the hydrogen(s) indicated with the arrow? 14

15 PRACTICE: Which one of the following best represents the predicted approximate chemical shift and coupling for the hydrogen(s) indicated with the arrow? 15

16 PRACTICE: The 1 H NMR spectrum of which of the compounds below, all of formula C 7 H 12 O 2, would consist of two singlets only? 16

17 PRACTICE: Consider the expected 1 H NMR spectrum of 1,1,3,3-tetramethylcyclopentane. Which of the following is likely to be observed? PRACTICE: Which isn t true about 13 C NMR spectroscopy? a) Each distinct carbon produces a single peak in 13 C NMR spectrum. b) Splitting of signals into multiple peaks is not observed in routine 13 C NMR spectra. c) Decreased electron density around an atom shields the atom from the magnetic field. d) Larger mass of samples is usually required. e) 13 C spectra are usually less complex and easier to interpret than 1 H NMR. 17

18 PRACTICE: An unidentified compound has the formula C 3 H 6 and shows only one 1 H NMR signal. Propose a structure. 18

19 PRACTICE: The 1 H NMR spectrum of a compound with formula C 7 H 14 O gives two signals. Which of these structures is a possible one for this compound? A) 2-Heptanone B) 3-Heptanone C) 2,4-Dimethyl-3-pentanone D) 2,2-Dimethyl-3-pentanone E) Two of the above PRACTICE: A compound with molecular formula C 12 H 24 exhibits a 1 H NMR spectrum with only one signal and a 13 C NMR spectrum with two signals. Deduce the structure of this compound. 19