NMRanalyst Sample Application: Verbenol

Verbenol
NMRanalyst Sample Application

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Sample Description:

Molecular Formula: C₁₀H₁₆O
Molecular Weight: 152.233

InChI=

1/C10H16O/c1-6-4-9(11)8-5-7(6)10(8,2)3/h4,7-9,11H,5H2,1-3H3

IUPAC Name:

4,6,6-Trimethylbicyclo[3.1.1]hept-3-en-2-ol

CAS Number: 18881-04-4
PubChem: 61126
NMRShiftDB: 10021322
Spectrometer: Varian INOVA 500 MHz
Solvent: CDCl₃
Sample Concentration: 49 mg for 1D carbon, 8 mg for other spectra

Provided by:

Dr. Charles L. Mayne, University of Utah

*.fid	np	nt	sw	rfp-rfl	ni	sw1	rfp1-rfl1	time

proton	160000	16	10000	-2503.71				2 m 43 s
carbon	524288	1000000	50000	-16647.02				22 m 2 s
hmbc	8192	8	4366.10	-414.46	1024	25000	-4314.10	31 h 57 m
hmqc	2048	8	4366.10	-413.81	512	25000	-1830.56	18 h 36 m

1D Proton Spectrum:

1D Carbon Spectrum (Deuterated Solvent and TMS Resonances Subtracted):

Automated VerifyIt Proton Assignments:

Automated VerifyIt Carbon Assignments:

Top 10 FindIt Molecular Structures Consistent With Molecular Formula and Proton Resonances:

The correct structure is at position 1.


 Best 10 structures in decreasing rating (structure ID shown in parentheses):
    1: 0.964759 (   61126)    2: 0.963595 (  527032)    3: 0.963285 ( 6428927)
    4: 0.961481 (  349147)    5: 0.960085 (  576906)    6: 0.959715 (  170304)
    7: 0.959690 (  520984)    8: 0.958384 ( 6428796)    9: 0.957570 (   62842)
   10: 0.957196 (  561871)

Top 10 FindIt Molecular Structures Consistent With Proton and Carbon Resonances:

The correct structure is at position 3.


 Best 10 structures in decreasing rating (structure ID shown in parentheses):
    1: 0.915841 ( 6428927)    2: 0.905663 (  527032)    3: 0.902126 (   61126)
    4: 0.891130 (  573227)    5: 0.883639 (  249596)    6: 0.883551 ( 6365962)
    7: 0.880624 (  557576)    8: 0.869403 (  349147)    9: 0.868830 ( 6430778)
   10: 0.867749 (  590302)

2D HMQC Spectrum:

Determined HMQC Correlations:

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

The correct structure is at position 1.


 Best 10 structures in decreasing rating (structure ID shown in parentheses):
    1: 0.912314 (   61126)    2: 0.910734 (  527032)    3: 0.907350 (  162747)
    4: 0.896619 (  118088)    5: 0.894939 ( 8028799)    6: 0.894329 ( 7332995)
    7: 0.889530 (  557576)    8: 0.888102 ( 8447365)    9: 0.886796 ( 9903146)
   10: 0.886505 (  102553)

2D Phase Sensitive HMBC Spectrum:

AssembleIt HSQC (HMQC) & HMBC Derived Carbon-Carbon Correlations:

AssembleIt Derived Structure With NMRgraph Added Likely Oxygen Atoms:

Most likely structure (out of 5 possible ones) by agreement with carbon chemical shift prediction

Comments:

Verbenol is a monoterpenoid pheromone.

This was our first structure elucidated using indirect detection spectra. Since 1999, we have considerably improved this approach.

NMRanalyst supports twelve spectrum types. The verbenol HMQC spectrum is analyzed using NMRanalyst's HSQC spectrum type. The HMQC spectrum was acquired without multiplicity editing. If NMRanalyst does not consider multiplicity editing, HSQC detected carbons are shown as CH groups (three free valences). This results in thousands of verbenol structures. But the carbon shift agreement still identifies the correct one.

Here NMRanalyst is instructed to assume HSQC multiplicity editing. Without observed negative HSQC correlations, no carbons are reported as CH₂. But likely CH₃ carbons are identified. Multiplicity editing should be used for the acquisition of all HSQC spectra. It is faster to acquire than a 1D DEPT spectrum and simplifies the structure elucidation.

The verbenol HMBC spectrum shows prominent T1 ridges. Today such spectra are preferably acquired using Pulse Field Gradients (PFG) as shown by the other demo datasets.

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