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One N (one + n)

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Chemistry100%

Selected Abstracts

Piperidone derivative from Dalbergia sympathetica

MAGNETIC RESONANCE IN CHEMISTRY, Issue 3 2005
N. Shanmugam Nagarajan
Abstract An alcoholic extract of Dalbergia sympathetica, on column chromatography, yielded a compound which analyzed for C6H11NO3 (M+ 145). The IR spectrum of the compound showed the presence of carbonyl and hydroxyl groups. PMR, 13C and DEPT NMR spectral studies of the compound showed the presence of one N -methyl, two methine and two methylene groups. A quaternary carbon signal at , 172.88 ppm was assigned to C-2 carbonyl of the compound. From all the above observations and also from the HMQC 2D NMR spectrum, the compound was identified as 3, 6-dihydroxy- N -methyl-2-piperidone. This is the first report of the natural occurrence of this compound from plant sources. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Thermally induced intramolecular oxygen migration of N -oxides in atmospheric pressure chemical ionization mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 19 2010
Xin Wang
N -Oxides are known to undergo three main thermal degradation reactions, namely deoxygenation, Cope elimination (for N -oxides containing a ,-hydrogen) and Meisenheimer rearrangement, in atmospheric pressure chemical ionization mass spectrometry (APCI-MS). The ions corresponding to these thermal degradants observed in the ensuing APCI mass spectra have been used to identify N -oxides as well as to determine the N -oxidation site when the analyte contains multiple tertiary amine groups. In this paper, we report a thermally induced oxygen migration from one N -oxide amine to another tert -amine group present in the same molecule through a six-membered ring transition state during APCI-MS analysis. The observed intramolecular oxygen migration resulted in the formation of a new isomeric N -oxide, rendering the results of the APCI-MS analysis more difficult to interpret and potentially misleading. In addition, we observed novel degradation behavior that happened after the Meisenheimer rearrangement of the newly formed N -oxide: a homolytic cleavage of the NO bond instead of elimination of an aldehyde or a ketone that usually follows the rearrangement. Understanding of these unusual degradation pathways, which have not been reported previously, should facilitate structural elucidation of N -oxides using APCI-MS analysis. Copyright © 2010 John Wiley & Sons, Ltd. [source]

Three isomeric 1-(2-chloronicotinoyl)-2-(nitro­phenyl)hydrazines, including three polymorphs of 1-(2-chloronicotinoyl)-2-(2-nitrophenyl)hydrazine: hydrogen-bonded supramolecular structures in two and three dimensions

ACTA CRYSTALLOGRAPHICA SECTION B, Issue 1 2007
Solange M. S. V. Wardell
1-(2-Chloronicotinoyl)-2-(2-nitrophenyl)hydrazine, C12H9Cl­N4O3, crystallizes in three polymorphic forms, two monoclinic forms in space groups Cc (Ia) and P21 (Ib), and an orthorhombic form in space group Pbcn (Ic). In the Cc polymorph (Ia) the molecules are linked into sheets by combinations of one N,H,O and two C,H,O hydrogen bonds, while in the P21 polymorph (Ib) the molecules are linked into sheets by combinations of three hydrogen bonds, one each of N,H,O, C,H,N and C,H,O types. In the orthorhombic polymorph (Ic) the molecules are linked into a complex three-dimensional framework structure by a combination of one N,H,O, one N,H,N and three C,H,O hydrogen bonds, and an aromatic ,,, stacking interaction. In the isomeric compound 1-(2-chloronicotinoyl)-2-(3-nitrophenyl)hydrazine (II) the molecules are again linked into a three-dimensional framework, this time by a combination of three hydrogen bonds, one each of N,H,O, N,H,N and C,H,O types, weakly augmented by a ,,, stacking interaction. The molecules of 1-(2-chloronicotinoyl)-2-(4-nitrophenyl)hydrazine (III) are linked into sheets by a combination of three hydrogen bonds, one each of N,H,O, N,H,N and C,H,O types. [source]

Isomeric N -(iodophenyl)nitrobenzamides form different three-dimensional framework structures

ACTA CRYSTALLOGRAPHICA SECTION B, Issue 5 2006
James L. Wardell
The isomeric N -(iodophenyl)nitrobenzamides, C13H9IN2O3, all form different three-dimensional framework structures. Molecules of N -(2-iodophenyl)-3-nitrobenzamide (II) are linked by a combination of N,H,O and C,H,O hydrogen bonds and a two-centre iodo,carbonyl interaction. The supramolecular structure of N -(2-iodophenyl)-4-nitrobenzamide (III) is built from one N,H,O and two C,H,O hydrogen bonds, but short I,O contacts are absent from the structure. In N -(3-iodophenyl)-2-nitrobenzamide (IV), which crystallizes with Z, = 2 in space group P21, the structure contains two N,H,O hydrogen bonds, four C,H,O hydrogen bonds, two two-centre iodo,nitro interactions and an aromatic ,,, stacking interaction. The structure of N -(3-iodophenyl)-3-nitrobenzamide (V) contains one N,H,O hydrogen bond and three C,H,O hydrogen bonds, together with a two-centre iodo,nitro interaction and an aromatic ,,, stacking interaction, while in N -(3-iodophenyl)-4-nitrobenzamide (VI), the combination of one N,H,O hydrogen bond and two C,H,O hydrogen bonds is augmented not only by a two-centre iodo,nitro interaction and an aromatic ,,, stacking interaction, but also by a dipolar carbonyl,carbonyl interaction. In the supramolecular structure of N -(4-iodophenyl)-4-nitrobenzamide (IX), which crystallizes with Z, = 2 in space group , there are two N,H,O hydrogen bonds, four C,H,O hydrogen bonds and two three-centre iodo,nitro interactions. [source]

Double anomeric effects and a hydrogen-bonded supramolecular motif in N,N,-bis(3-nitrophenyl)methanediamine

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2009
Zhenfeng Zhang
In the title compound, C13H12N4O4, the molecule lies on a crystallographic twofold axis. Molecules are linked into complex sheets parallel to (100) via one N,H...O and two C,H...O hydrogen bonds. Within the molecule, the 3-nitroanilino fragment is essentially planar, and the C,N,C,N,C fragment assumes a nearly perpendicular/perpendicular conformation, with C,N,C,N torsion angles of 81.18,(18)°, which is controlled by a pair of adjacent anomeric interactions. The findings constitute the first demonstration of two anomeric effects existing in one N,C,N unit. [source]