- Beyond the five and six: Evaluation of seven-membered cyclic anhydrides in the castagnoli-cushman reaction
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The Castagnoli-Cushman reaction with benzo[d]- oxepine-2,4(1H,5H)-dione as an anhydride component allowed for preparation of 2,3-disubstituted 4-oxo-2,3,4,5-tetrahydro-1H-benzo[d]- azepine-1-carboxylic acids in 21-75% yields and with good trans diastereoselectivity. The method worked with imines generated from aromatic or a-branched aliphatic aldehydes and is amenable for both parallel synthesis and scale-up. The procedure for epimerization of the resulting trans-disubstituted tetrahydrobenzo[d]azepines to their cis isomers was also developed.
- Adamovskyi, Mykhailo I.,Ryabukhin, Sergey V.,Sibgatulin, Dmitriy A.,Rusanov, Eduard,Grygorenko, Oleksandr O.
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supporting information
p. 130 - 133
(2017/09/08)
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- The interplay of secondary Hg...S, Hg...N and Hg...π bonding interactions in supramolecular structures of phenylmercury(ii) dithiocarbamates
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Three new phenylmercury(ii) and one mercury(ii) dithiocarbamate complexes viz. PhHg S2CN(PyCH2)Bz (1), PhHg S 2CN(PyCH2)CH3 (2), PhHg S2CN(Bz) CH3 (3), and [Hg (NCS2(PyCH2)Bz)2] (4) (Py = pyridine; Bz = benzyl) have been synthesized and characterized by elemental analyses, IR, electronic absorption, 1H and 13C NMR spectroscopy. The crystal structures of 1, 2 and 3 showed a linear S-Hg-C core at the centre of the molecule, in which the metal atom is bound to the sulfur atom of the dithiocarbamate ligand and a carbon atom of the aromatic ring. In contrast the crystal structure of 4 showed a linear S-Hg-S core at the Hg(ii) centre of the molecule. Weak intermolecular Hg...N (Py) interactions link molecules into a linear chain in the case of 1, whereas chains of dimers are formed in 2 through intermolecular Hg...N (Py) and Hg...S interactions. 3 forms a conventional face-to-edge dimeric structure through intermolecular Hg...S secondary bonding and 4 forms a linear chain of dimers through face-to-face Hg...S secondary bonding. In order to elucidate the nature of these secondary bonding interactions and the electronic absorption spectra of the complexes, ab initio quantum chemical calculations at the MP2 level and density functional theory calculations were carried out for 1-3. Complexes 1 and 2 exhibited photoluminescent properties in the solid state as well as in the solution phase. Studies indicate that Hg...S interactions decrease and Hg...N interactions increase the chances of photoluminescence in the solid phase The Royal Society of Chemistry 2011.
- Singh, Vikram,Kumar, Abhinav,Prasad, Rajendra,Rajput, Gunjan,Drew, Michael G. B.,Singh, Nanhai
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experimental part
p. 6817 - 6826
(2012/04/11)
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- Structural-activity relationship study of highly-functionalized imidazolines as potent inhibitors of nuclear transcription factor-κB mediated IL-6 production
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We herein describe the synthesis and anti-inflammatory properties of a small library of imidazoline-based NF-κB inhibitors. The structure-activity relationship of various substituents on an imidazoline core structure was evaluated for the ability to inhibit NF-κB mediated IL-6 production. Optimization of the scaffolds was pursued by correlating luciferase-based NF-κB reporter assays with inhibition of IL-6 production in IL-1β stimulated human blood. Several derivatives were found to inhibit NF-κB mediated IL-6 production in the nanomolar range in IL-1β stimulated human blood.
- Kahlon, Daljinder K.,Lansdell, Theresa A.,Fisk, Jason S.,Tepe, Jetze J.
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experimental part
p. 3093 - 3103
(2009/10/02)
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- Aminophosphinic acids in a pyridine series, Part 2: Synthesis of 2-, 3-, and 4-pyridyl derivatives of 1-(Benzylamino)-methyl-H-phosphinic Acids
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New 2-pyridyl, 3-pyridyl, and 4-pyridyl derivatives of 1-[N-(benzyl)amino]- methyl-H-phosphinic acid were prepared by the addition of bis(trimethylsilyl) phosphonite to the corresponding imines and subsequent methanolysis of the addition products. Treatment of the 2-pyridyl- and 1-(4-pyridyl)-1-(benzylamino) -methyl-H-phosphinic acids with aqueous mineral acids leads to cleavage and formation of the corresponding secondary amines and phosphorous acid (H3PO3).
- Goldeman, Waldemar,Boduszek, Bogdan
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experimental part
p. 1413 - 1425
(2010/03/24)
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- Aminophosphinic acids in a pyridine series: Cleavage of pyridine-2- and pyridine-4-methyl(amino)phosphinic acids in acidic solutions
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The synthesis of a series of new pyridine aminomethylphosphinic acids is described. These compounds were obtained in the reaction of the corresponding pyridine aldehydes with primary amines and with ethyl phenylphosphinate, or methylphosphinate, in the presence of bromotrimethylsilane. In aqueous, strong acid solutions, pyridine aminophosphinic acids were split, forming the phenyl-, or methylphosphonic, acid and the corresponding secondary pyridyl-alkylamines. The kinetics of some observed cleavages were measured, and a mechanism of the cleavage has been proposed. Copyright Taylor & Francis Group, LLC.
- Boduszek, Bogdan,Olszewski, Tomasz,Goldeman, Waldemar,Konieczna, Magdalena
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p. 787 - 795
(2007/10/03)
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- Aminophosphine oxides in a pyridine series. Studies on the cleavage of pyridine-2- and pyridine-4-yl-(N-benzylamino)-methyldiphenylphosphine oxides in acidic solutions
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The synthesis and reactions of 1-(N-benzylamino)-1-(2-pyridyl)- and 1-(N-benzylamino)-1-(4-pyridyl)-methyldiphenylphosphine oxides are described. It was found that these compounds were exceptionally easy to cleave in aqueous sulfuric acid solutions to form diphenylphosphinic acid and the corresponding N-(pyridylmethyl)-benzylamines. The structure of a single diastereoisomer, that is, the (R)-(+)-1-[N-(α-methylbenzylamino)]-1-(4-pyridyl)-(S)-methyldiphen ylphosphine oxide was determined by X-ray crystallography. The acidic alcoholysis of the selected model chiral pyridine aminophosphine oxides was investigated by means of 31P NMR spectroscopy. The cleavage kinetics were also studied. On the basis of the obtained results, a mechanism of the cleavage was formulated.
- Goldeman, Waldemar,Olszewski, Tomasz K.,Boduszek, Bogdan,Sawka-Dobrowolska, Wanda
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p. 4506 - 4518
(2007/10/03)
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- Multicomponent synthesis of highly substituted imidazolines via a silicon mediated 1,3-dipolar cycloaddition
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A diastereoselective multicomponent synthesis of highly functionalized imidazolines is reported. A silicon mediated 1,3 dipolar cycloaddition of the in situ generated münchnone with an imine resulted in the formation of highly substituted imidazolines. The imidazolines contain a four-point diversity and two stereocenters and the cycloaddition reaction is applicable to aryl, alkyl, acyl, and heterocyclic substitutions.
- Peddibhotla,Tepe
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p. 1433 - 1440
(2007/10/03)
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- A Simple Synthesis of Pyridine Aminophosphinic Acids and Pyridine Aminophosphine Oxides. The Unusual Cleavage of Pyridylmethyl-(N-benzylamino)-phenylphosphinic Acids and Phosphine Oxides in Acidic Solutions
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Pyridine aminophosphinic acids were synthesized in reaction, of N-(benzyl)-pyridylmethylimines with ethyl phenylphosphinate, in the presence of bromotrimethylsilane. Pyridine aminophosphine oxides were obtained in excellent yields by treatment of the corresponding imines with diphenylphosphine oxide. Among these compounds, the 2-pyridyl and 4-pyridyl derivatives were subject to a simple cleavage in aqueous mineral acid solutions. Products of the cleavages were N-(pyridylmethyl)benzylamines and phenylphosphonic (or diphenylphosphinic) acid, respectively.
- Boduszek, Bogdan
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p. 4087 - 4094
(2007/10/03)
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- A novel four-component synthesis of N-substituted amino acid esters
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A library of N-substituted amino acid esters was synthesized using a solid phase bound organic isocyanide that provides a C1 synthon to the final molecule. This novel four-component, one-pot reaction delivers the final products in acceptable yields with high purities of the crude reaction products, facilitating the final purification. The preparation of the isocyano resin is also described the intermediates being controlled by ATR-spectroscopy.
- Henkel, Bernd,Weber, Lutz
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p. 1877 - 1879
(2007/10/03)
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- The acidic cleavage of pyridylmethyl(amino)phosphonates. Formation of the corresponding amines
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Hydrolysis of 3-pyridylmethyl(amino)phosphonates by means of 20% aq. hydrochloric acid gave corresponding 3-pyridimethyl(amino)phosphonic acids, as expected. However, hydrolysis of 2- and 4-pyridylmethyl(amino)phosphonates led to decomposition of the phosphonates with a cleavage of C-P bond and formation of the corresponding amines. The leaving phosphorus moiety was identified as phosphoric acid. The scope of the reaction is limited to 2- and 4-pyridylmethyl derivatives of aminophosphonic acids and their esters, as well as to the derivatives possessing similar structure. On the contrary, the basic hydrolysis of 2- and 4-pyridylmethyl(amino)phosphonates led to the corresponding monoalkyl esters of the aminophosphonates, and no cleavage of C-P bond was observed in those cases.
- Boduszek, Bogdan
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p. 12483 - 12494
(2007/10/03)
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- 1-aminophosphonic acids and esters bearing heterocyclic moiety. Part 2. 1 pyridine, pyrrole and emidazole derivatives
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The benzylic amines (benzylamine, benzhydrylamine and benzyl carbamate) were applied in the synthesis of aminophosphonates derived from pyridine, pyrrole and imidazole. The Schiff bases obtained from corresponding heterocyclic aldehydes and benzylic amines were caused to react with diphenyl phosphorate or dibenzyl phosphonate to form corresponding heterocyclic aminophosphonates in good yields. The N-(benzylamino)-phosphonates were deblocked by catalytic hydrogenolysis. The benzhydryl group from the phosphonates was removed by acidic hydrolysis, and the carbobenzyloxy group from the phosphonates can be easy removed by treatment with a solution of 30% HBr in acetic acid, as well. It was found that during acidic hydrolysis of 2-and 4-pyridylmethylaminophosphonates a rearrangement occurred, combined with a cleavage of C-P bond in the phosphonate molecules and subsequent formation of the corresponding amines.
- Boduszek, Bogdan
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p. 209 - 218
(2007/10/03)
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- 31. Synthesis of a masked p-quinone methide β-lactam as an active metabolite of nocardicins
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Nocardicin A analogues 30, 34, and 38 as well as the highly strained quinone methide 43 were synthesized. β-Lactam 34 was found biologically active against several Gram-negative microorganisms in vitro; pyridinium N-oxide derivative 38 possessed activity
- Hakimelahi,Tsay,Hwu
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p. 411 - 420
(2007/10/02)
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- Acidities of Glycine Schiff Bases and Alkylation of Their Conjugate Bases
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Equilibrium acidities in Me2SO are reported for six ketimines of the type Ph2C=NCH(R)CO2Et and five aldimines, ArCH=NCH(R)CO2Et.Changing R in the ketimine from H to Ph increased the pKa by 2.2 units.This surprising acidity decrease for Ph substitution points to a substantial increase in steric effect, as do the increases in pKa of 3.8 and 4.2 units observed for the replacement of hydrogen by Me and PhCH2, respectively.Phase-transfer alkylation of the Ph2C=NCH2CO2Et ketimine gave over 90 percent of monoalkylate whereas, under similar conditions, the aldimine 4-ClC6H4CH=NCH2CO2Et gave a mixture of mono- and dialkylate.The difference is that the pKa of the monoalkylated aldimine is essentially the same as that of the parent, which leads to rapid equilibration with the parent anion and consequent dialkylation.The rates of alkylation in Me2SO of these parent and monoalkylated anions did not differ greatly, showing that the relative pKHAs of the parent acid and its monoalkyl derivative, rather tham the relative rates of the mono- and dialkylation reactions, is the principal factor that determines the extent of the competition between monoalkylation and dialkylation.
- O'Donnell, Martin J.,Bennett, William D.,Bruder, Willian A.,Jacobsen, William N.,Knuth, Keith,et al.
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p. 8520 - 8525
(2007/10/02)
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