NMRanalyst Sample Application: Quinine

Quinine
NMRanalyst Sample Application

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Sample Description:

Molecular Formula: C₂₀H₂₄N₂O₂
Molecular Weight: 324.417

InChI=

1/C20H24N2O2/c1-3-13-12-22-9-7-14(13)10-19(22)20(23)16-6-8-21-18-5-4-
15(24-2)11-17(16)18/h3-6,8,11,13-14,19-20,23H,1,7,9-10,12H2,2H3

IUPAC Name:

6'-Methoxycinchonan-9-ol

CAS Number: 56-54-2
PubChem: 1065
NMRShiftDB: 10016314
Spectrometer: Bruker AV 400 MHz
Probe: 1mm MicroProbe
Solvent: CDCl₃
Sample Concentration: ca. 200 µg

Provided by:

Dr. Till Kühn, Bruker BioSpin

Directory	npF2	NS	swF2	spF2	npF1	swF1	spF1	time

proton (300)	32768	32	8802.82	-2382.52				3 m 35 s
gDQF-COSY (301)	1024	2	3591.95	105.76	512	3591.95	105.76	1 h 26 m
gHSQC (302)	1024	12	4006.41	-101.47	256	16666.67	-829.60	2 h 32 m
gHMBC (303)	1024	40	3591.95	105.76	512	23148.15	-1529.29	10 h 28 m
N15-gHMBC (305)	1024	2048	4006.41	15.85	16	16220.60	-2028.58	18 h 18 m

1D Proton Spectrum:

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

The correct structure is at position 7.


 Best 10 structures in decreasing rating (structure ID shown in parentheses):
    1: 0.957622 (  102439)    2: 0.957340 ( 3499717)    3: 0.955644 (   65753)
    4: 0.955078 (  847715)    5: 0.953062 ( 6336167)    6: 0.953047 (  585971)
    7: 0.952892 (    1065)    8: 0.950814 (    8547)    9: 0.949068 (  934598)
   10: 0.948731 ( 2037943)

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: 0.937466 (    1065)    2: 0.915501 ( 6336167)    3: 0.900599 ( 3499717)
    4: 0.897815 (  183259)    5: 0.895740 ( 3083557)    6: 0.894629 (  101764)
    7: 0.894536 (   84495)    8: 0.891677 ( 4835740)    9: 0.890939 ( 3809868)
   10: 0.889296 ( 5191849)

Automated VerifyIt Proton Assignments:

Automated VerifyIt Carbon Assignments:

2D DQF-COSY Spectrum:

AssembleIt HSQC & DQF-COSY Derived Carbon-Carbon Correlations:

AssembleIt HSQC & DQF-COSY Derived Correlations

2D N15_HMBC Spectrum:

AssembleIt HSQC & N15_HMBC Derived Nitrogen-Carbon Correlations:

AssembleIt HSQC & N15_HMBC Derived Correlations

2D HMBC Spectrum:

AssembleIt HSQC, HMBC, DQF-COSY & N15_HMBC Derived Correlations:

AssembleIt Derived Structure With NMRgraph Added Likely Oxygen Atoms:

Most likely structure (out of 277 possible ones) by agreement with carbon chemical shift prediction

Comments:

Quinine is used as an antimalaria drug.

Before performing a full structure elucidation, consider running FindIt. Only the molecular formula, proton, and/or (potentially only protonated) carbon shift information are needed.

At natural abundance, a 1D carbon spectrum is 5,700 times less sensitive to acquire than a 1D proton spectrum. Acquiring the shown HSQC and HMBC spectra instead is still faster than acquiring one 1D carbon spectrum. The full quinine structure elucidation is demonstrated using about 200 micro grams of sample. Only the shown NMR data from a room-temperature 1 mm capillary probe are used. No molecular formula (MF) or information from other spectroscopic methods are needed.

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