thought process. Budget your time wisely – not all questions are of identical point value nor are all questions of comparable difficulty. 11 Spectra for a compound C 8 H 16 O 2 were recorded. Answer the questions below based on your interpretation of those spectra. Please record magnetic resonance peaks in order of increasing values of chemical shift ( δ) . A From the infrared spectrum of this compound below, fill in the table with the assignment of the types of bonds responsible for the significant peaks in the spectrum. (2 pt. total) Frequency (cm-1) Assignment 2970 C-H 1733 C=O 1367 C-O 1160 C-O What functional group is present in this compound? (2 pt.) C=O, C-O (ester?)
Name________ key ______________ Date__________________________ B From the pmr spectrum of this compound, complete the table below with the information requested. Please record magnetic resonance peaks in order of increasing values of chemical shift ( δ) . (0.5 pt. @ = 10 pt. total) Identifier Shift ( δ ) Multiplicity Integration #H Assignment a 0.93 triplet 0.26 3H CH 3 b 1.4 singlet 0.83 9H 3 * CH 3 c 1.6 Sextet 0.17 2H CH 2 d 2.2 triplet 0.17 2H CH 2 XXX XXX Total = 1.43 XXX Show one sample of how the calculation of the number of hydrogens for each of the signals was carried out. (2 pt.) Integration Calculation 1.43 / 16H = 0.26 / xH x = 2.9 ≈ 3H 1.43 / 16H = 0.83 / xH x = 9.3 ≈ 9H 1.43 / 16H = 0.17 / xH x = 1.9 ≈ 2H
Name________ key ______________ Date__________________________ C From the cmr/DEPT-135 spectra of the unknown, complete the table below with the DEPT-135 response and the assignment of the carbon signal. Please record magnetic resonance peaks in order of increasing values of chemical shift ( δ) δ) . (0.5 pt. @) = 9 pt. total) Identifier Shift DEPT-135 (-, 0, +) Assignment (CH 3 , CH 2 , etc.) A 13.6 + CH 3 B 18.6 - CH 2 C 28.1 + CH 3 D 37.5 - CH 2 E 79.9 0 C w/ no H F 173.2 0 C=O
Name________ key ______________ Date__________________________ D From information in the COSY spectrum, indicate which protons couple with other protons. (table of data = 2 pt., correlation diagram on the graph = 3 pt.)) Identifier Multiplicity Coupled proton(s) Multiplicity(s) of coupled proton(s) a triplet c sextet b singlet - - c sextet a, d triplet, triplet d triplet c sextet
Name________ key ______________ Date__________________________ E From the information in the HETCOR spectrum, indicate which protons are attached to which carbons. (Data table = 2 pt., correlation diagram on the graph = 3 pt.) cmr identifier cmr shift Correlated pmr identifier pmr shift A 13.6 a 0.93 B 18.6 c 1.6 C 28.1 b 1.4 D 37.5 d 2.2 E - - -
Name________ key ______________ Date__________________________ F Propose a structure for the unknown compound whose spectra you have analyzed.
- Spring '16
- Organic chemistry, Amide, Amides, C=O bond, Name________key______________, Date__________________________