scholarly journals Synthesis of Novel 3,7-Diazabicyclo[3.3.1]nonane Derivatives

2013 ◽  
Vol 16 (1) ◽  
pp. 85
Author(s):  
A.Ye. Malmakova ◽  
K.D. Praliyev ◽  
J.T. Welch ◽  
T.K. Iskakova ◽  
S.S. Ibraeva
Keyword(s):  
Spectral Characteristics ◽  
Triethylene Glycol ◽  
Chair Conformation ◽  
Primary Amines ◽  
Reaction Products ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Eluent Benzene ◽  
Bicyclic Ketones ◽  
C Nmr

<p>A series of 3-(3-ethoxypropyl)-7-heterocyclylalkyl-3,7-diazabicyclo[3.3.l]nonan-9-ones have been prepared by Mannich cyclocondensation of 1-(3-ethoxypropyl)-4-oxopiperidine with paraformaldehyde and primary amines followed by Wolff-Kischner reduction of the obtained bispidinones. The starting 1-(3-ethoxypropyl)-4-oxopiperidine was synthesized by Dickmann condensation of 3-ethoxypropylamine with ethylacrylate. The 3,7-diazabicyclo[3.3.1]nonanones were obtained in acceptable yields by condensation of 1-(3-ethoxypropyl)piperidin-4-one with primary amines: 1-(3-aminopropyl)imidazole or 1-(2-aminoethyl) piperazine and formaldehyde in the presence of acetic acid in methanol medium. Reduction of the obtained bispidinones with hydrazine hydrate was carried out in the presence of KOH in triethylene glycol at 160-170 °C for 5 hours. The syntheses were performed under the atmosphere of N<sub>2</sub>. As the reaction products are viscous oils, the column chromatography (on III activity aluminum oxide, eluent – benzene: dioxane 5:1) was used for purification of novel bicyclic ketones and bicyclic nonanes. The completion of the reactions was monitored by TLC. Methods of <sup>1</sup>H and <sup>13</sup>C NMR spectroscopy were used to determine the structures of the substances synthesized. The prior studies have demonstrated that variation on the substituents at nitrogen atoms in 3- and 7-positions of bispidine cycle could result in the increase of biological activity and effect on compound spectral characteristics. Spatial structures of bispidinones and related bispidines were determined on the basis of the data of the <sup>13</sup>C and <sup>1</sup>H NMR spectra. A doublet of doublets of equatorial protons at C<sub>2.4 </sub>and C<sub>6.8</sub> with large geminal constants of 10.5-11 Hz and vicinal constants of 3.0-6.0 Hz in <sup>1</sup>H NMR spectrum revealed that those 3,7-diazabicyclo[3.3.1]nonane derivatives have a “chair-chair” conformation of both piperidine rings.</p>

Accelerated hydrolysis of boronic acid in a modified poly(amidoamine) dendrimer: identification of a factor leading to the production of an impurity in boronic acid containing poly(amidoamine) dendrimers

2017 ◽  
Vol 95 (9) ◽  
pp. 984-990 ◽  
Author(s):  
Ching-Hua Tsai ◽  
Yu-Wen Fang ◽  
Hui-Ting Chen ◽  
Chai-Lin Kao
Keyword(s):  
Boronic Acid ◽  
Hydrolysis Product ◽  
Pamam Dendrimer ◽  
Primary Amines ◽  
Alizarin Red ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Icp Ms ◽  
Hydrolysis Of ◽  
C Nmr

The preparation of boronic acid containing dendrimers is still a difficult task in dendrimer chemistry. In this investigation, an unanticipated hydrolysis product (4) was identified during the preparation of (G:2)-PAMAM-dendri-(4-phenyl boronic acid)14 (3) by acquiring its 1H NMR, 13C NMR, and UV–vis absorption spectra and IR spectra and comparing them with those of 4-hydroxylbenzoic acid (5). Furthermore, an Alizarin Red S staining analysis, ICP-MS, and 11B NMR spectrum indicated the lack of boronic acid in 4. Finally, treatment of 3 with hydrogen peroxide gave a product that was determined to be identical to dendrimer 4. By analyzing the formation of 4 under various conditions, the presence of numerous primary amines in a PAMAM dendrimer did accelerate the hydrolysis of peripheral boronic acid. This investigation revealed an apparent intrinsic problem that needs to be overcome during the preparation of boronic acid containing dendrimers and related boronic acid containing macromolecules.

21,22-Disubstituted 18α,19βH-Ursane Derivatives with Oxabicyclooctane System in Ring E

1993 ◽  
Vol 58 (1) ◽  
pp. 173-190 ◽  
Author(s):  
Eva Klinotová ◽  
Jiří Klinot ◽  
Václav Křeček ◽  
Miloš Buděšínský ◽  
Bohumil Máca
Keyword(s):  
Spectral Data ◽  
Spin Systems ◽  
Coupling Constants ◽  
Complete Analysis ◽  
Nmr Spectrum ◽  
Proton Proton ◽  
H Nmr ◽  
Proton Coupling ◽  
C Nmr

Reaction of 3β-acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) and 20β,28-epoxy-21,22-dioxo-19α,19βH-ursan-3β-yl acetate (IIIb) with diazomethane afforded derivatives XII-XIV with spiroepoxide group in position 21 or 22, which were further converted into hydroxy derivatives XV and XVII. Ethylene ketals VIII-X were also prepared. In connection with the determination of position and configuration of the functional groups at C(21) and C(22), the 1H and 13C NMR spectral data of the prepared compounds are discussed. Complete analysis of two four-spin systems in the 1H NMR spectrum of bisethylenedioxy derivative Xb led to the proton-proton coupling constants from which the structure with two 1,4-dioxane rings condensed with ring E, and their conformation, was derived.

scholarly journals 1-Norbornyl cation may be in equilibrium with 2-norbornyl cation

2019 ◽  
Vol 45 ◽  
pp. 146867831986131
Author(s):  
Andrew Mamantov
Keyword(s):  
Nmr Spectrum ◽  
Future Studies ◽  
H Nmr ◽  
C Nmr

New 1H and 13C NMR 400 MHZ spectra of the 2-Nb cation under stable ion conditions, for example, in SbF5/SO2F2/SO2ClF, −80 oC, show besides the usual 1H NMR resonances at δ 4.93, 2.82, 1.85, the never before seen singlet, δ 9.63, and doublet, δ 2.97 (J2,6 = 16.6 Hz), ratio 1.00 : 1.07, proposed to be due to resonance-stabilized bridgehead 1-Nb cationic enantiomers in equilibrium with 2-Nb cation. The corresponding 13C proton-coupled NMR spectrum, −80 oC, has a C3,5,7 triplet, δ 30.45, J(CH) = 139.14 Hz, and C4 doublet, δ 37.7, J(CH) = 154.54 Hz. The C1,2,6 absorption, δ 91.04 is relatively broad, whereas previously, at −70 oC, it was a pentuplet. The 13C proton-decoupled spectrum at −80 oC shows the C4 doublet and C3,5,7 triplet collapsed to a singlet, but the C1,2,6 resonance is still broad. Analyses support the slowing exchange between resonance stabilized enantiomeric 2-cations at ≤ –159 oC. Some future studies are proposed.

Synthesis and Purification of L-Phenylalanine Oligo-Peptides Assisted by Phosphorus Oxychloride

2011 ◽  
Vol 365 ◽  
pp. 150-154
Author(s):  
Ming Xiu Lv ◽  
Li Ming Qiang ◽  
Kui Lu ◽  
Ying Yan Yao
Keyword(s):  
Self Assembly ◽  
Phosphorus Oxychloride ◽  
Inorganic Phosphorus ◽  
The Self ◽  
Reaction Products ◽  
Esi Ms ◽  
H Nmr ◽  
Rp Hplc ◽  
Proper Condition ◽  
C Nmr

Oligo-peptides have been focused on by chemists recently because of the strong bioactivity an activity as drug or precursor of drug. α-Amino acid could self-assemble into oligo-peptides with the assistance of inorganic phosphorus reagents, so it could provide a new method to synthesize peptides. In this paper, the self-assembly reaction of L-Phenylalanine mediated by phosphorus oxychloride were studied by using ESI-MS. The proper condition of self-assembly reaction of L-Phe was reported. The reaction products were purified by RP-HPLC and Phe-Phe dipeptide was characterized by the means of IR, 1H-NMR, 13C-NMR and ESI-MS/MS.

Synthesis and characterization of silver(I) complexes of thioureas and thiocyanate: crystal structure of polymeric (1,3-diazinane-2-thione)thiocyanato silver(I)

2015 ◽  
Vol 70 (8) ◽  
pp. 541-546 ◽  
Author(s):  
Muhammad Nawaz Tahir ◽  
Anvarhusein A. Isab ◽  
Fozia Afzal ◽  
Kashif Raza ◽  
Shah Muhammad ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Nmr Spectrum ◽  
Coordination Environment ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Ir And Nmr Spectroscopy ◽  
A Chain ◽  
Distorted Tetrahedral Coordination ◽  
C Nmr

AbstractSilver(I) complexes of thioureas and thiocyanate, [(Tu)AgSCN], [(Metu)AgSCN], [(Dmtu)AgSCN], [(Tmtu)(AgSCN)1.5], [(Imt)AgSCN], and [(Diaz)AgSCN] (where Tu = thiourea, Metu = N-methylthiourea, Dmtu = N,N′-dimethylthiourea, Tmtu = N,N,N′,N′-tetramethylthiourea, Imt = 1,3-imidazolidine-2-thione, and Diaz = 1,3-diazinane-2-thione), have been prepared and characterized by elemental analysis, IR and NMR spectroscopy, and thermal analysis. The crystal structure of one of them, [(Diaz)Ag(SCN)] (1), was determined by X-ray crystallography. The crystal structure of 1 shows that the complex exists in the form of a chain-like polymer comprising [Ag(μ2-Diaz)(μ2-SCN)] units. The silver atoms are bridged by μ2-thione sulfur atoms of Diaz and μ2-thiocyanate sulfur atoms. Thereby each silver atom adopts a distorted tetrahedral coordination environment comprising four sulfur atoms, two from thione and two from thiocyanate ligands. An upfield shift in the >C=S resonance of thiones in 13C NMR and a downfield shift in the N–H resonance in 1H NMR are consistent with the sulfur coordination to silver(I). The appearance of a band around 2100 cm–1 in the IR and a resonance around 125 ppm in the 13C NMR spectrum indicates the binding of thiocyanate to silver(I).

The series Os4(µx-η2-C2Ph2)(CO)14–n (n = 0, 1, 2; x = n + 2) — Models for site-specific surface catalysts

2006 ◽  
Vol 84 (2) ◽  
pp. 176-186 ◽  
Author(s):  
John P Canal ◽  
Michael C Jennings ◽  
Glenn PA Yap ◽  
Roland K Pomeroy
Keyword(s):  
Specific Surface ◽  
Slow Rotation ◽  
Nmr Spectrum ◽  
Site Specific ◽  
H Nmr ◽  
Metal Atoms ◽  
Surface Catalysis ◽  
The Common ◽  
Exchange Surface ◽  
C Nmr

The cluster Os4(µ-η2-C2Ph2)(CO)14 (1) has been prepared from the reaction of Os4(CO)14 and C2Ph2 in CH2Cl2 at 25 °C. Other minor products include the known clusters Os3(µ3-η2-C2Ph2)(CO)10 and Os3(µ-η4-C4Ph4)(CO)9. The structure of 1 reveals an approximately planar C2Os4 skeleton with a dimetallacyclobutene ring (C—C = 1.32(4) Å) and a flat butterfly Os4 unit (Os—Os range = 2.859(2)–2.916(2) Å). The 13C{1H} NMR spectrum of 1 indicates the carbonyl ligands are rigid at room temperature. Stirring 1 in CH2Cl2 for 2 days (ambient temperature) afforded Os4(µ3-η2-C2Ph2)(CO)13 (2). The Os atoms in 2 also have an almost flat butterfly arrangement (Os—Os range = 2.7392(7)–2.8947(6) Å) with the alkyne ligand located over one of the Os3 triangles. The 13C NMR data for 2 are consistent with rapid rotation on the NMR timescale of the hinge Os(CO)3 units at 21 °C, but slow rotation at –50 °C. Heating 2 at 40 °C gave Os4(µ4-η2-C2Ph2)(CO)12 (3) after 2 days. Cluster 3 has the common butterfly arrangement of Os atoms with the C2Ph2 bound to all four metal atoms (Os—Os range = 2.7457(5)–2.8742(5) Å). The 13C{1H} NMR spectra of 3 at 21 and 90 °C indicate there is rapid CO exchange of the carbonyls of the two types of Os(CO)3 units, but not between the units. The spectrum at –90 °C indicates one of the rotations (presumed to be that involving the carbonyls of the wingtip Os(CO)3 units) is slowed on the NMR timescale. Compounds 1–3 form a unique series of clusters that have an alkyne ligand bound to two, three, and four metal atoms. Compound 1 is a model for a corner, compound 2 for a planar surface, and compound 3 a step site, in site-specific surface catalysts.Key words: osmium cluster, diphenylacetylene, dimetallacyclobutene, carbonyl exchange, surface catalysis.

Part II. Conformational analysis of 4- and 5-substituted thiazolidine-2-thiones

1980 ◽  
Vol 58 (6) ◽  
pp. 604-616 ◽  
Author(s):  
F. Chanon ◽  
M. Rajzmann ◽  
M. Chanon ◽  
J. Metzger ◽  
G. Pouzard ◽  
...  
Keyword(s):  
Chemical Shifts ◽  
Alkyl Substituent ◽  
Chair Conformation ◽  
Equatorial Orientation ◽  
Anomeric Effect ◽  
H Nmr ◽  
Transannular Interaction ◽  
Conformational Properties ◽  
Out Of Plane ◽  
C Nmr

Variation of the conformational properties in a series of 4-R-thiazolidine-2-thiones (4-R = Me, Et, iPr, tBu, OH) and 5-R-thiazolidine-2-thiones (5-R = Me, Et, iPr, tBu) is deduced from 1H nmr (Karplus 3J, chemical shifts, 2J44′, 2J55′) 13C nmr data and CNDO-2 calculations. In the absence of any transannular interaction, vicinal constraints and van der Waals requirements of the substituents control the conformational equilibrium. The pseudo-axial arrangement is favoured when 4-R = Me, while the substituent presents no preferential orientation when 5-R = Me. As the size of the 5-alkyl and the 4-alkyl substituent increases, its pseudo-equatorial orientation and the predominance of the C4C5 out-of-plane half-chair conformation are favoured. This does not lead to conformational exclusivity even when 4-R or 5-R is tBu. When 4-R is hydroxy, there is a definite pseudo-axial conformation (anomeric effect) and the ring preference is of the C4 out-of-plane type.

Syntheses of New Triethylene Glycol Bis(alkyl Phosphate)s as Potential Complexing Agents

2001 ◽  
Vol 66 (4) ◽  
pp. 621-630 ◽  
Author(s):  
Věra Novoměstská ◽  
Eckhard Herrmann ◽  
Přemysl Lubal ◽  
Jiří Příhoda
Keyword(s):  
Ir Spectroscopy ◽  
Mass Spectroscopy ◽  
Elemental Analysis ◽  
Metal Cations ◽  
Triethylene Glycol ◽  
Complexing Agents ◽  
H Nmr ◽  
Maldi Tof ◽  
Alkyl Phosphate ◽  
C Nmr

A series of triethylene glycol bis(alkyl phosphate)s HO(RO)P(O)(OCH2CH2)3OP(O)(OR)OH 4 (R = octyl (4a), 1-methylheptyl (4b), 2-ethylhexyl (4c), nonyl (4d), decyl (4e), dodecyl (4f), hexadecyl (4g), octadecyl (4h)) has been synthesized with the expectation that these compounds could be effective complexing and/or extraction agents for metal cations. The compounds were characterized by 31P NMR, 1H NMR, 13C NMR and IR spectroscopy, MALDI-TOF mass spectroscopy and elemental analysis.

Liquefaction Mechanism of β-O-4 Lignin Model Compound in the Presence of Phenol under Acid Catalysis. Part 1. Identification of the Reaction Products

Holzforschung ◽  
2001 ◽  
Vol 55 (6) ◽  
pp. 617-624 ◽  
Author(s):  
L. Lin ◽  
Y. Yao ◽  
N. Shiraishi
Keyword(s):  
High Performance ◽  
Model Compound ◽  
Structural Characteristics ◽  
Main Reaction ◽  
Reaction Products ◽  
Lignin Model Compound ◽  
H Nmr ◽  
Lignin Model ◽  
Oxalic Acids ◽  
C Nmr

Summary Guaiacylglycerol-β-guaiacyl ether (GG) was used as a lignin model compound to study the liquefaction reaction mechanism of lignin in the presence of phenol under the catalysis of several typical acids such as sulfuric, phosphoric and oxalic acids. The reaction products were isolated by silicagel column chromatography and high performance liquid chromatography (HPLC). The structures of the obtained compounds were identified by means of GC-MS, 1H-NMR, 13C-NMR, 1H-1H COSY, HMBC and HMQC. As a result, about 30 compounds were obtained as the main reaction products. It was found that their structural characteristics were significantly different from those yielded at the non-catalyzed liquefaction (Lin et al. 1997a), and independent on the acid species. The dominant products were guaiacylglycerol-α-phenyl-β-guaiacyl ethers, followed by guaiacol, triphenylethanes, diphenylmethanes, benzocyclobutanes and phenylcoumarans. The structural characteristics and yields of these main reaction products indicated that condensation between phenol and GG in its C-α and further cleavages in both the β-O-4 linkage and Cβ–Cγ bonding could be the dominant reaction pathways.

scholarly journals Total assignment of the1H and13C NMR spectra of piperovatine

1998 ◽  
Vol 14 (1) ◽  
pp. 35-40 ◽  
Author(s):  
Willy Rendón ◽  
Galia Chávez ◽  
Myriam Meléndez-Rodríguez ◽  
Pedro Joseph-Nathan
Keyword(s):  
Chemical Shift ◽  
Chemical Shift Correlation ◽  
Nmr Spectrum ◽  
Quaternary Carbon Atom ◽  
H Nmr ◽  
Simulation Based ◽  
Complete Assignment ◽  
Nmr Methods ◽  
Unambiguous Assignment ◽  
C Nmr

Total and unambiguous assignment of the1H NMR spectrum of piperovatine [6‒(4‒methoxyphenyl)‒N‒(2‒methylpropyl)‒2,4‒hexadienamide] was carried out using conventional 1D NMR methods and spectral spin–spin simulation. Based on these data, the complete assignment of the13C NMR chemical shift values was made by a13C/1H chemical shift correlation diagram and conventional considerations for the quaternary carbon atom.

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