Ch 9 14 15 Problems

Ch 9 14 15 Problems - EXTRA PROBLEMS FOR EXAM 1(Ch 9 14 15 Ch 9 NMR Questions Chem 345 SFN 1.a Write the number of signals in the proton-decoupled

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EXTRA PROBLEMS FOR EXAM 1 (Ch. 9, 14, 15) Ch. 9 NMR Questions Chem. 345 SFN 1.a. Write the number of signals in the proton-decoupled 13 C NMR spectrum for each isomer: MeO OMe OMe OMe MeO OMe MeO OMe A B C D For isomers with the same number of signals, how could you tell them apart by 13 C NMR? 1.b. Write in the hydrogens on the structure, assign different hydrogens letters from left to right, and sketch the 1 H NMR spectrum, showing multiplicities, number of H causing the signal, and your letter assignments for each group of peaks. 1.b.1 0 δ 5 10 O O 1.b.2 0 δ 5 10 O
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2 2. Interpreting 1 H-NMR spectra. When asked for a part-structure, you must circle the H’s being observed to get full credit. 2.a. C 4 H 7 ClO 2 . The “3” and “4 are integrations of the regions shown _____ DBE Part-structure from “3” region Part structures from “4” region [Note: signals for two types of H partially overlap] Complete structure (label the proper H’s with letters, and insert them on the spectrum) 2.b. The signal at the right integrates for one H. 2.b.1. From the chemical shift, give a part-structure that is consistent 2.b.2 Show two part-structures that might be consistent with the multiplicity. You cannot tell exactly what substituents are attached, but should be able to suggest ones that are consistent with the chemical shift. Circle the observed hydrogen
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3 3. Interpreting 1 H-NMR spectra. When asked for a part-structure, you must circle the H’s being observed to get full credit. 3.a. C 5 H 9 BrO 2 NOTE: Signals overlap in region A! Part-structure from region B: Part-structure from region C: Complete structure (letter the proper H’s) 3.b. Empirical formula C 3 H 8 O From the scales shown, this spectrum was taken on a ____ MHz NMR Part-structure from region C Compound structure: The separation of the peaks is ~0.11 δ in region C and 0.08 δ in region A. Write the J values on your structure. Why doesn’t the A region obey the (n+1) rule?
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4 4. D E TMS A B C A B C D E From the molecular formula (C 11 H 14 O), what is IHD (DBE)? ________ Regions A and B are not first order. What information do you get from the chemical shifts ( δ s) and integrations in these regions? Give the structural information obtained from the sets of peaks shown as
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This note was uploaded on 02/14/2011 for the course ORGANIC CH 341 taught by Professor Idk during the Spring '11 term at Wisconsin.

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Ch 9 14 15 Problems - EXTRA PROBLEMS FOR EXAM 1(Ch 9 14 15 Ch 9 NMR Questions Chem 345 SFN 1.a Write the number of signals in the proton-decoupled

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