NMRanalyst Sample Application: Prednisone

Prednisone
NMRanalyst Sample Application

NMRanalyst

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Sample Description:

Molecular Formula: C₂₁H₂₆O₅
Molecular Weight: 358.433

InChI=

1/C21H26O5/c1-19-7-5-13(23)9-12(19)3-4-14-15-6-8-21(26,17(25)11-22)
20(15,2)10-16(24)18(14)19/h5,7,9,14-15,18,22,26H,3-4,6,8,10-11H2,1-2H3

IUPAC Name:

17,21-Dihydroxypregna-1,4-diene-3,11,20-trione

CAS Number: 53-03-2
PubChem: 4900
NMRShiftDB: 20126
Spectrometer: Varian INOVA 500 MHz
Solvent: DMSO-d₆
Sample Concentration: 3.6 mg/ml

Provided by:

Dr. Péter Sándor, Varian Deutschland GmbH

*.fid/text file specifies: Prednisone 3.6mg/ml (10 mmolar in DMSO-d6)
*.fid	np	nt	sw	rfp-rfl	ni	sw1	rfp1-rfl1	time

proton	36048	8	4506.03	-242.81				34 s
carbon	72636	100000	27972.03	-290.51				4 h 51 m
ghmbc	2048	8	4506.03	-242.81	4200	27972.03	-290.51	1 h 37 m
ghsqc	1802	8	4506.03	-242.81	256	19493.18	1337.64	48 m 2 s

1D Proton Spectrum:

1D Carbon Spectrum (Deuterated Solvent 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 2.


 Best 10 structures in decreasing rating (structure ID shown in parentheses):
    1: 0.968931 (  224451)    2: 0.964962 (    4900)    3: 0.961961 (  111256)
    4: 0.960555 ( 5289127)    5: 0.959142 ( 2325247)    6: 0.953170 ( 1637016)
    7: 0.949951 ( 3912718)    8: 0.949821 (  161779)    9: 0.948734 ( 8519198)
   10: 0.948612 ( 3011532)

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

The correct structure is at position 1.


 Best 10 structures in decreasing rating (structure ID shown in parentheses):
    1: 0.940860 (    4900)    2: 0.917751 ( 3034026)    3: 0.876398 (   91438)
    4: 0.874900 (  124653)    5: 0.868520 (    4063)    6: 0.866013 ( 4118075)
    7: 0.862965 (   31051)    8: 0.862695 (   31052)    9: 0.861430 (   85675)
   10: 0.856061 (  259332)

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: 0.939478 (    4900)    2: 0.914714 ( 1776826)    3: 0.912472 (  908271)
    4: 0.901324 ( 3034026)    5: 0.899277 (  111337)    6: 0.895611 ( 5356013)
    7: 0.895588 ( 6390934)    8: 0.893448 ( 1794048)    9: 0.889996 (  249702)
   10: 0.889564 (   91438)

2D HMBC Spectrum:

AssembleIt HSQC & HMBC Derived Carbon-Carbon and HX-Carbon Correlations:

AssembleIt Derived Structure With NMRgraph Added Likely Oxygen Atoms:

Most likely structure (out of 3 possible ones) by AssembleIt rating and by agreement with carbon chemical shift prediction

Comments:

Prednisone is used for the treatment of skin problems, artritis, inflammation, and allergic reactions.

FindIt clearly identifies the correct structure.

The prednisone sample was dissolved in DMSO-d₆. This solvent sufficiently slows the proton exchange for both hydroxyl groups to show HMBC correlations. NMRanalyst identifies heteroatom protons by an "H" followed by the proton resonance frequency in ppm (here H 5.56 and H 4.64). These additional HMBC correlations are of great help for the full structure elucidation in proton poor areas of the molecule.

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