Solution Found!
For each compound shown below,(1) Sketch the 13C NMR
Chapter 18, Problem 41SP(choose chapter or problem)
For each compound shown below,
(1) Sketch the \({ }^{13} C\) NMR spectrum (totally decoupled, with a singlet for each type of carbon), showing approximate chemical shifts.
(2) Show the multiplicity expected for each signal in the off-resonance-decoupled spectrum.
(3) Sketch the spectra expected using the DEPT-90 and DEPT-135 techniques.
Equation transcription:
Text transcription:
^{13} C
Questions & Answers
QUESTION:
For each compound shown below,
(1) Sketch the \({ }^{13} C\) NMR spectrum (totally decoupled, with a singlet for each type of carbon), showing approximate chemical shifts.
(2) Show the multiplicity expected for each signal in the off-resonance-decoupled spectrum.
(3) Sketch the spectra expected using the DEPT-90 and DEPT-135 techniques.
Equation transcription:
Text transcription:
^{13} C
ANSWER:Solution:-
The NMR for the off-resonance decoupled spectrum is given below. Here the chemical shift () is represented as s = singlet , d = doublet, t = triplet, q = quartet.
Step 1
NMR spectrum spectrum of ethyl acetate:-
The DEPT -90 spectrum have no peaks due to the absence of CH group.
DEPT 135 (Distortionless Enhancement of Polarization Transfer) using a 135 degree decoupler pulse.
Spectral Interpretation - This pulse sequence produces a carbon spectrum with methyl (CH3) and methyne (CH) carbons are up. Methene (CH2) carbons are down.
