NMRanalyst Sample Application: 3,6-Dioxo-2,3,4,6-tetrahydropyrazino[2,1-a]isoindole-1-carbonitrile

3,6-Dioxo-2,3,4,6-tetrahydropyrazino
[2,1-a]isoindole-1-carbonitrile
NMRanalyst Sample Application

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Sample Description:

Molecular Formula: C₁₂H₇N₃O₂
Molecular Weight: 225.203

InChI=

1/C12H7N3O2/c13-5-9-11-7-3-1-2-4-8(7)12(17)15(11)6-10(16)14-9/h1-4H,6H2,
(H,14,16)/f/h14H

IUPAC Name:

3,6-Dioxo-2,3,4,6-tetrahydropyrazino[2,1-a]isoindole-1-carbonitrile

PubChem: 5326134
NMRShiftDB: 30000160
Spectrometer: Bruker AMX 400 MHz
Solvent: DMSO-d₆

Provided by:

Institut Organische Chemie, Universitaet Mainz (inhouse database)

Directory	npF2	NS	swF2	spF2	npF1	swF1	spF1	time

proton (1)	16384	32	6410.256	-1197.499				1 m 54 s
carbon (2)	16384	9400	25000.000	-1418.611				2 h 45 m
cosy (3)	1024	8	4032.258	-108.496	128	4032.258	-108.496	1 h 8 m
edited hmqc (4)	1024	12	4032.258	-358.497	128	18111.960	-958.848	2 h 8 m
hmbc (5)	1024	12	4032.258	-358.497	256	20126.000	-978.400	2 h 8 m

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 1.


 Best 10 structures in decreasing rating (structure ID shown in parentheses):
    1: 0.970239 ( 5326134)    2: 0.950590 ( 5449437)    3: 0.935907 ( 5826209)
    4: 0.920151 ( 9915180)    5: 0.913847 ( 4808231)    6: 0.912755 (  478015)
    7: 0.910040 (  338713)    8: 0.908638 (  377858)    9: 0.899773 (  478013)
   10: 0.882169 (   38763)

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

The correct structure is at position 4.


 Best 10 structures in decreasing rating (structure ID shown in parentheses):
    1: 0.887457 (  571723)    2: 0.886694 ( 1989871)    3: 0.885365 (  579568)
    4: 0.883699 ( 5326134)    5: 0.881755 (  336572)    6: 0.876942 ( 5101376)
    7: 0.875227 ( 2192104)    8: 0.874190 (  457779)    9: 0.873735 ( 2304925)
   10: 0.872759 ( 4963662)

2D Multiplicity-Edited HMQC Spectrum:

Determined HMQC Correlations:

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

The correct structure is at position 1.


 Best 10 structures in decreasing rating (structure ID shown in parentheses):
    1: 0.894112 ( 9255836)    2: 0.889289 (  571723)    3: 0.884899 ( 5326134)
    4: 0.882889 ( 1989871)    5: 0.879791 (  615894)    6: 0.878052 (  336572)
    7: 0.875647 (  457779)    8: 0.875638 ( 2304925)    9: 0.873523 ( 3263189)
   10: 0.872633 ( 4963662)

2D (DQF?) COSY Spectrum:

AssembleIt HMQC & (DQF?) COSY Derived Carbon-Carbon Correlations:

AssembleIt HMQC & (DQF?) COSY Derived Correlations

2D HMBC Spectrum:

AssembleIt HSQC (HMQC), HMBC & DQF-COSY Derived Correlations:

Comments:

The 11 ppm proton resonance (corresponding to a 0.91 H integral) originates from the NH in proximity to the CN group. FindIt identifies the correct structure with molecular formula and proton resonances.

In the carbon spectrum, the undetected resonance around 110 ppm is the middle of the spectrum glitch and should not be detected. The "cosygs" pulse sequence used is not a phase sensitive one as recommended. It also does not appear to be a DQF filtered one. Due to a F1 resolution worse than 30 Hz/point, the sinc wiggles extend far in the F1 dimension. Various weighting functions might limit these ridges. But this would not help the determination of the coupling constants, which is essential to distinguish 3-bond from longer range proton-proton correlations in a DQF-COSY spectrum. This spectrum probably should not be used. But it identifies the three bonds between protonated carbons of this molecule.

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