NMRanalyst Sample Application: 2-Ethyl-1-indanone

2-Ethyl-1-indanone
NMRanalyst Sample Application
Structure Elucidation Without 1D Carbon Spectrum

NMRanalyst

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Sample Description:

Molecular Formula: C₁₁H₁₂O
Molecular Weight: 160.212

InChI=

1/C11H12O/c1-2-8-7-9-5-3-4-6-10(9)11(8)12/h3-6,8H,2,7H2,1H3/t8-/m0/s1

IUPAC Name:

2-Ethylindan-1-one

CAS Number: 22351-56-0
PubChem: 640236
NMRShiftDB: 20292
Spectrometer: Varian Mercury 200 MHz
Solvent: CDCl₃
Sample Concentration: Unknown

Provided by:

Dr. Iain Green, Varian Inc.

*.fid/text file specifies: 2-ethylind in CDCl3
*.fid	np	nt	sw	rfp-rfl	ni	sw1	rfp1-rfl1	time

proton	7988	16	1996.81	-98.52				50 s
ghmbc	512	32	2000	-100.12	200	12062.73	-751.60	2 h 10 m
hsqc	512	16	2000	-100.12	128	8547.01	-502.25	1 h 21 m

1D Proton Spectrum:

2D Multiplicity-Edited HSQC Spectrum:

Determined HSQC Correlations:

Top 10 FindIt Molecular Structures Consistent With Proton and Protonated Carbon (HSQC) Resonances:

The correct structure is at position 1.


 Best 10 structures in decreasing rating (structure ID shown in parentheses):
    1: 0.823370 (  906067)    2: 0.800939 (   32182)    3: 0.786087 (  233139)
    4: 0.781089 (  297794)    5: 0.777187 (  340277)    6: 0.775213 (  599772)
    7: 0.771687 (  287590)    8: 0.767951 (  427019)    9: 0.767928 (  201732)
   10: 0.765187 (  348685)

2D HMBC Spectrum:

AssembleIt HSQC & HMBC Derived Carbon-Carbon Correlations:

AssembleIt Derived Structure With NMRgraph Added Likely Oxygen Atoms:

Most likely structure (out of 2 possible ones) by agreement with carbon chemical shift prediction

Comments:

When the HSQC and HMBC spectra are acquired with sufficient F1 resolution, no separate 1D carbon spectrum needs to be acquired. The incentive for eliminating the 1D carbon spectrum is its acquisition time is longer than that for the 1D proton, edited HSQC, and HMBC spectra combined.

Here are the steps for determining the 2-ethyl-1-indanone carbon list from the 2D spectra:

cp -r 2-ethyl-1-indanone 2-ethyl-1-indanone_no1D13C
cd 2-ethyl-1-indanone_no1D13C
rm -r carbon.*

Start NMRanalyst. Switch to HMBC 1D Analysis workwindow.
Set the "Input File Format" menu to [Generate Generic List].
Copy the 2D FFT F1 spectral description values: "Observe Frequency" to 50.289 MHz, "Spectral Width" to 12062.726 Hz, "Start of Spectrum" to -763.508 Hz, "Number of Points" to 200. Run the workwindow. => 48 generic carbon resonances result.

Switch to HSQC 2D Analysis workwindow.
Set "Map F1 Frequencies +/-" to 150 Hz. Select the F1 and F2 phase optimization for mapping and detection. Delete all phase functions.
In the Report workwindow, set "Redetermined F1 Resonance List" to carbon_hsqc.out.
Run the 2D Analysis workwindow and it auto-runs the Report workwindow. => 8 carbon resonances result from the HSQC.

Switch to HMBC 2D Analysis workwindow.
Set "F2 1D Analysis Output File" to HSQC/report.log and "Map F1 Frequencies +/-" to 150 Hz.
Set the Report workwindow "Redetermined F1 Resonance List" to carbon_hmbc.out.
Run the 2D Analysis workwindow and it auto-runs the Report workwindow. => 11 carbon resonances result from the HMBC.

merge2list carbon_hsqc.out carbon_hmbc.out 0.3 > ncarbon.out

Then remove the above HSQC, HMBC 2D Analysis and Report workwindow input field changes. Replace references to the generic "carbon.out" to the updated "ncarbon.out" carbon list. Rerun the HSQC and HMBC analysis. The structure elucidation results are identical to the ones obtained using the 1D carbon spectrum (cf. 2-ethyl-1-indanone).

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