Triazene derivatives of (1,x)-diazacycloalkanes. Part III. Synthesis and characterization of a series of 1,4-di[2-aryl-1-diazenyl]piperazines

2005 ◽  
Vol 83 (5) ◽  
pp. 471-476 ◽  
Author(s):  
Vanessa Renée Little ◽  
Reid Tingley ◽  
Keith Vaughan
Keyword(s):  
Mass Measurement ◽  
Variable Temperature ◽  
Molar Ratio ◽  
Diazonium Salts ◽  
Piperazine Ring ◽  
Nmr Data ◽  
Ir And Nmr Spectroscopy ◽  
Reported Data ◽  
Derivatives Of

Reaction of a series of diazonium salts with piperazine in a 2:1 molar ratio affords excellent yields of the 1,4-di-[2-aryl-1-diazenyl]piperazines (3), which have been characterized by IR and NMR spectroscopy. Structural characterization is supported by elemental analysis or by mass spectrometry with accurate mass measurement of the molecular ion. The protons of the piperazine ring hydrogens give rise to a sharp singlet at ca. 4 ppm in the NMR spectra, indicating that the conformational equilibrium in the piperazine ring is rapid on the NMR timescale. The four equivalent carbon atoms of the piperazine ring resonate in the range 46–48 ppm. A variable temperature NMR experiment suggests that there is restricted rotation around the N2—N3 bond of the triazene moiety in 3. The NMR data compares favorably with previous reported data for 1-aryldiazenyl-4-methylpiperazines (1) and 1,4-di-(2-aryldiazen-1-yl)homopiperazines (2b).Key words: triazene, piperazine, diazonium coupling, NMR.

Triazene derivatives of (1,x)-diazacycloalkanes — Part IX. Synthesis and characterization of a series of 1,4-di[2-aryl-1-diazenyl]-2,6-dimethylpiperazines

2010 ◽  
Vol 88 (4) ◽  
pp. 344-351 ◽  
Author(s):  
Naomi Hunter ◽  
Keith Vaughan
Keyword(s):  
Diazonium Salt ◽  
Mass Measurement ◽  
2D Nmr ◽  
Piperazine Ring ◽  
Ir And Nmr Spectroscopy ◽  
Methylene Groups ◽  
Type 3 ◽  
Derivatives Of

A series of 1,4-di-[2-aryl-1-diazenyl]-2,6-dimethylpiperazines (5a–5l), have been synthesized by the reaction of 2,6-dimethylpiperazine with 2 equiv. of the appropriate diazonium salt. The products have been characterized by IR and NMR spectroscopy, and the molecular composition has been verified by high-resolution EI mass spectrometry with accurate mass measurement of the molecular ion. The presence of stereocenters at C2 and C6 of the piperazine ring in the bis-triazene 5 creates two unique pairs of diastereotopic protons in the methylene groups at positions 3 and 5 of the piperazine ring, as evidenced by the complexity of the NMR spectra, which nevertheless can be fully assigned in most cases. The assignment of the proton and carbon signals in the 1,4-di-[2-aryl-1-diazenyl]-2,6-dimethylpiperazines has been aided by the use of 2D NMR HSQC spectroscopy. These results compare favorably with assignments of proton and carbon signals reported previously for triazenes of type 1 and bis-triazenes of type 3.

Triazene derivatives of (1,x)-diazacycloalkanes. Part X. Synthesis and characterization of a series of 1,4-di[2-aryl-1-diazenyl]-trans-2,5-dimethylpiperazines

2014 ◽  
Vol 92 (7) ◽  
pp. 665-669 ◽  
Author(s):  
Vanessa Renee Little ◽  
Reid Tingley ◽  
Keith Vaughan
Keyword(s):  
Nmr Spectra ◽  
Diazonium Salt ◽  
Mass Measurement ◽  
2D Nmr ◽  
Piperazine Ring ◽  
Ir And Nmr Spectroscopy ◽  
Methylene Groups ◽  
Derivatives Of

A series of 1,4-di[2-aryl-1-diazenyl]-trans-2,5-dimethylpiperazines(5a–5m), have been synthesized by the reaction of trans-2,5-dimethylpiperazine with two equivalents of the appropriate diazonium salt. The products have been characterized by IR and NMR spectroscopy, and the molecular composition has been verified by high-resolution EI mass spectrometry with accurate mass measurement of the molecular ion. The presence of stereocenters at C2 and C5 of the piperazine ring in the bis-triazene (5) creates two unique pairs of diastereotopic protons in the methylene groups at positions 3 and 6 of the piperazine ring, as evidenced by the complexity of the NMR spectra, which nevertheless can be fully assigned in some cases, such as the anisyl- (5i) and phenyl- (5j) derivatives. The assignment of the proton and carbon signals in the tolyl- derivative (5h) has been aided by the use of 2D NMR HSQC spectroscopy. These results compare favorably with assignments of proton and carbon signals reported previously for triazenes of type 1 and bis-triazenes of types 3 and 4b.

Triazene derivatives of (1,x)-diazacycloalkanes. Part IV.1 Synthesis and characterization of 1-[2-aryl-1-diazenyl]-3-(3-[2-aryl-1-diazenyl]hexahydro-1-pyrimidinylmethyl)hexahydropyrimidines and 1-(5,5-dimethyl-3-[2-aryl-1-diazenyl]hexahydro-1-pyrimidinylmethyl)-5,5-dimethyl-3-[2-aryl-1-diazenyl]hexahydropyrimidines from the reaction of diazonium salts with mixtures of formaldehyde and 1,3-diaminopropanes

2005 ◽  
Vol 83 (8) ◽  
pp. 1071-1083 ◽  
Author(s):  
Shasta Moser ◽  
Ryan Church ◽  
M Brad Peori ◽  
Keith Vaughan
Keyword(s):  
High Resolution Mass Spectrometry ◽  
Diazonium Salts ◽  
X Ray ◽  
X Ray Crystallography ◽  
Ir And Nmr Spectroscopy ◽  
Analogous Manner ◽  
New Compounds ◽  
Bicyclic Molecules ◽  
Derivatives Of

Two new series of bistriazenes have been synthesized from a general reaction of diazonium salts with a mixture of a propanediamine and formaldehyde. Such reaction with 1,3-diaminopropane itself affords the 1-[2-aryl-1-diazenyl]-3-(3-[2-aryl-1-diazenyl]hexahydro-1-pyrimidinylmethyl)hexahydropyrimidines (6). 2,2-Dimethyl-1,3-diamino propane reacts in an analogous manner to give the 1-(5,5-dimethyl-3-[2-aryl-1-diazenyl]hexahydro-1-pyrimidinylmethyl)- 5,5-dimethyl-3-[2-aryl-1-diazenyl]hexahydropyrimidines (7). All new compounds have been characterized by IR and NMR spectroscopy, with elemental analysis or high resolution mass spectrometry of most of the new compounds. NMR assignments have been analyzed by a series of DEPT, COSY, and HSQC experiments. One example of each series has been unequivocally characterized by X-ray crystallography. The general conclusion of this study is that alkanediamines with three carbon atoms in the spacer link between the nitrogen atoms give rise to the linear bicyclic molecules of type 18, in contrast to the case of ethylenediamine (spacer link has two carbon atoms), which affords cage-like molecules of type 17.Key words: bistriazene, hexahydropyrimidine, diazonium coupling, formaldehyde, diaminopropane, nuclear magnetic resonance.

Triazene derivatives of (1,x)-diazacycloalkanes. Part V.1 Synthesis and characterization of 4-ethyl-3-({6-ethyl-3-[2-aryl-1-diazenyl]hexahydro-1-pyrimidinyl}methyl)-1-[2-aryl-1-diazenyl)hexa- hydropyrimidines from the reaction of diazonium salts with mixtures of formaldehyde and 1,3-diaminopentane

2005 ◽  
Vol 83 (10) ◽  
pp. 1799-1807 ◽  
Author(s):  
Reid Tingley ◽  
M Brad Peori ◽  
Ryan Church ◽  
Keith Vaughan
Keyword(s):  
Diazonium Salts ◽  
X Ray Crystallography ◽  
Ir And Nmr Spectroscopy ◽  
New Compounds ◽  
Bicyclic Molecules ◽  
Derivatives Of ◽  
Methylene Group ◽  
Single Bonds

A new series of bistriazenes has been synthesized from a general reaction of diazonium salts with a mixture of 1,3-diaminopentane (DYTEK® EP diamine) and formaldehyde, which affords the 4-ethyl-3-({6-ethyl-3-[2-aryl-1-diazenyl]hexahydro-1-pyrimidinyl}methyl)-1-[2-aryl-1-diazenyl]hexahydropyrimidines (1). Each of the molecules of type 1 is built up of two equivalent 3-(aryldiazenyl)-6-ethylhexahydro-1-pyrimidinyl groups attached to a central methylene group. The importance of this study is in part due to the fact that the formaldehyde–1,3-diaminopentane system has not previously been investigated. All new compounds have been characterized by IR and NMR spectroscopy, with elemental analysis for selected compounds; one example from the series has been unequivocally characterized by X-ray crystallography. Although analysis of the NMR spectra is made somewhat difficult because of broadness and coalescence of signals due to the rotational dynamics of the N—N single bonds, it is possible to fully assign the proton spectra of all compounds and to detect 94% of all carbon signals. The fine structure within the proton spectra illustrate the diastereotopic nature of the methylene group protons because of the presence of a stereocenter in each hexahydropyrimidine ring. The general conclusion of this study is that alkanediamines with three carbon atoms in the spacer link between the nitrogen atoms give rise to the linear bicyclic molecules of type 1, 2, and 3, in contrast to the case of ethylenediamine (spacer link has two carbon atoms), which affords molecules of type 7 that exemplify the bridged bicyclic bistriazene structure. The new compounds of series 1 represent an extension of a broad ranging study of the synthesis of new bistriazene derivatives of (1,x)-diazacycloalkanes.Key words: triazene, diazonium coupling, hexahydropyrimidine, diaminopentane, diazacycloalkanes, stereocenter, diastereotopic protons.

scholarly journals The isolation and further characterization of the bilirubin tetrapyrroles in bile-containing human duodenal juice and dog gall-bladder bile

1977 ◽  
Vol 167 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Ellen R. Gordon ◽  
Tak-Hang Chan ◽  
Karen Samodai ◽  
Carl A. Goresky
Keyword(s):  
Mass Spectrometry ◽  
Gall Bladder ◽  
Total Bilirubin ◽  
Molar Ratio ◽  
Diazonium Salts ◽  
Duodenal Juice ◽  
Human Bile ◽  
Total Pigment ◽  
The Individual

Bilirubin and its conjugates were extracted from either dog gall-bladder bile or bile-containing human duodenal juice into chloroform containing 10mm-tetraheptylammonium chloride. The intact bilirubin tetrapyrroles were then separated by t.l.c. Structural elucidation was made after coupling of the individual pigments with diazonium salts. Four azopigments were detected: azopigment αo or dipyrrolic azobilirubin; azopigment δ or dipyrrolic azobilirubin monoglucuronide; azopigment α3 or dipyrrolic azobilirubin monoglucoside; and, from dog gall-bladder bile, azopigment α2. The last conjugate required further verification of its structure. After methanolysis, it was shown by combined g.l.c.–mass spectrometry to contain xylose in a 1:1 molar ratio with the azopigments of bilirubin. Human bile contained 86% bilirubin diglucuronide, 7% bilirubin monoglucuronide monoglucoside diester, 4% bilirubin monoglucuronide and 3% bilirubin. Dog gall-bladder bile had a considerably different composition; it contained 47% bilirubin diglucuronide, 40% bilirubin monoglucuronide monoglucoside diester, 8% bilirubin monoglucuronide, 4% bilirubin diglucoside, 1–2% bilirubin and traces of conjugates containing xylose. The total bilirubin content and proportions of the conjugates did not change in bile that was frozen and stored at −20°C under N2, whereas in the chloroform/tetraheptylammonium chloride extract, similarly stored, total pigment was slowly lost and the diglucuronide conjugate converted into the monoglucuronide.

Synthesis and characterization of a series of 4-methyl-1-[2-aryl-1-diazenyl]-1,4-diazepanes and 1,4-di-[2-aryl-1-diazenyl]-1,4-diazepanes

2004 ◽  
Vol 82 (12) ◽  
pp. 1725-1735 ◽  
Author(s):  
Shasta Lee Moser ◽  
Keith Vaughan
Keyword(s):  
Nmr Assignments ◽  
Diazonium Salt ◽  
Variable Temperature ◽  
2D Nmr ◽  
Diazonium Salts ◽  
X Ray Diffraction ◽  
X Ray ◽  
New Compounds ◽  
C Nmr

1-Methylhomopiperazine was coupled with a series of diazonium salts to afford the 4-methyl-1-[2-aryl-1-diazenyl]-1,4-diazepanes (6), a new series of triazenes. These compounds are, in the main, stable crystalline solids (some of the series are stable oils), and they have been characterized by 1H and 13C NMR spectroscopy, IR spectroscopy, and mass spectrometry. NMR assignments were determined by 2D NMR and variable-temperature NMR experiments and by comparison with model compounds. A second series of new compounds, namely, 1,4-di-[2-aryl-1-diazenyl]-1,4-diazepanes (5), were prepared by coupling unsubstituted homopiperazine (1,4-diazepane) with 2 molar equivalents of the diazonium salt and were similarly characterized. The crystal and molecular structure of the parent member of this bis-triazene series (5, X = H) has been determined by single-crystal X-ray diffraction analysis.Key words: triazene, bis-triazene, diazenyl, bis-diazenyl, diazonium salt, NMR, diazepane.

scholarly journals Synthesis and Characterization of Some Trivalent and Tetravalent Derivatives of 2- Hydroxy-1-naphthoic Acid

2004 ◽  
Vol 1 (2) ◽  
pp. 110-114 ◽  
Author(s):  
Deepti Joshi ◽  
T. K. Joshi
Keyword(s):  
Spectral Data ◽  
Elemental Analysis ◽  
Molar Ratio ◽  
Synthesis And Characterization ◽  
Spectral Measurements ◽  
Mass Spectral ◽  
Naphthoic Acid ◽  
Derivatives Of

The trivalent derivatives (B, Al, As, Sb & Fe) and tetravalent derivatives (Si, Ti & Se) of 2-hydroxy-1-naphthoic acid have been prepared by the interaction of their corresponding isopropoxide with letter in different molar ratioviz. 1:3 &1:4 in benzene medium. The prepared compounds generally obtained as coloured solids and amongst them those containing isopropoxy groups were found to be hygroscopic. All these compound were characterized by azeotrope and elemental analysis as well as by IR, PMR and mass spectral measurements. These spectral data have facilitated in elucidating the mode of bonding of the said metals and non-metals in these compounds with 2-hydroxy-1-naphthoic acid.

Sulphur–nitrogen anions: 14N and 15N NMR investigations of the deprotonation of cyclic sulphur imides and sulphur–ammonia solutions

1992 ◽  
Vol 70 (3) ◽  
pp. 710-718 ◽  
Author(s):  
T. Chivers ◽  
K. J. Schmidt
Keyword(s):  
Nmr Spectroscopy ◽  
Sodium Azide ◽  
Liquid Ammonia ◽  
Molar Ratio ◽  
15N Nmr ◽  
Molar Ratios ◽  
Nmr Data ◽  
Nmr Characterization

The following systems have been investigated by 14N and (or)15N NMR spectroscopy: (a) the deprotonation of S7NH by n-BuLi, (b) solutions of S8, S7NH, 1,3- and 1,4-S6(NH)2, and K2SN2 in liquid ammonia, (c) the reaction of sodium azide with sulphur in hexamethylphosphoramide (HMPA), (d) the reactions of S7NH and S4(NH)4 with potassium amide in liquid ammonia in various molar ratios, and (e) the reaction of (NSCl)3 with potassium amide (1:6 molar ratio) in liquid ammonia. These investigations have provided an NMR characterization of the thermally unstable S7N− (δ15N ca. −324 ppm) and S2N2H− ions (δ14N + 7 and −149 ppm, 1J(14N−1H) 36 Hz, 1J(15N−H) 55 Hz, 2J(15N-15N) 2.2 Hz) in liquid ammonia, demonstrated the existence of S7N−, in addition to SSNSS−, as the major nitrogen-containing ingredient of sulphur–ammonia solutions (SAS), and confirmed the formation of the SSNSS−, but not S7N−, from the reaction of sodium azide and sulphur in HMPA. Consistent with previous chemical investigations, the NMR data show that the S7N− and S2N2H− ions are thermally unstable with respect to the formation of SSNSS− and S3N3−, respectively, in solution. Solutions of S4(NH)4/4KNH2 or (NSCl)3/6KNH2 show the same two 14N or 15N NMR resonances at ca. +97 and −108 ppm as a solution of NSN2− in liquid ammonia. Keywords: sulphur–nitrogen anions, nitrogen NMR, liquid ammonia.

scholarly journals The isolation and characterization of bilirubin diglucuronide, the major bilirubin conjugate in dog and human bile

1976 ◽  
Vol 155 (3) ◽  
pp. 477-486 ◽  
Author(s):  
E R Gordon ◽  
C A Goresky ◽  
T H Chang ◽  
A S Perlin
Keyword(s):  
Mass Spectrometry ◽  
Glucuronic Acid ◽  
Methyl Esters ◽  
Water Soluble ◽  
Molar Ratio ◽  
Human Bile ◽  
Isolation And Characterization ◽  
Azo Derivatives ◽  
Derivatives Of

The chemical structure of the major conjugate of bilirubin was unequivocally elucidated by structural analysis. The conjugated bilirubins were first separated from the lipid components of human duodenal aspirates or dog gall-bladder bile, and then resolved by t.l.c. into a series of tetrapyrroles. The major tetrapyrrole was then converted into its more stable dipyrrolic azo derivative for further analysis. The conjugated moiety of the azopigment was characterized after methanolysis with sodium methoxide. This reaction yields two types of product, those soluble in water and those soluble in organic solvents. The organic-soluble fraction was shown by t.l.c. and mass spectrometry to contain the methyl esters of the dipyrrolic azo derivatives of bilirubin. The water-soluble materials were analysed by enzymic procedures, t.l.c., n.m.r. spectrometry and combined g.l.c. and mass spectrometry. This analysis showed that the only water-soluble product resulting from the methanolysis was glucuronic acid. The structure was identical with that of pure standards, on both mass spectrometry and n.m.r. spectroscopy. No contaminating moieties were found. Quantitative measurement indicated that the glucuronic acid had been released in a 1:1 molar ratio with the resulting methyl esters of the dipyrrolic azo derivatives of bilirubin. This unequivocally establishes bilirubin diglucuronide as the major pigment present in bile. Past problems with identification of bilirubin diglucuronide were shown to originate from procedures which resulted in incomplete separation and isolation of the azopigments of the conjugated bilirubins, owing to contamination by biliary lipids.

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