NMR study of 3-t-butyl-1-([2.2]paracyclophan-4-yl)-5-phenylverdazyl1

NMR measurements on the title verdazyl 5a and on specifically deuterated derivatives 5b-5f gave clear assignments of the proton hyperfine coupling constants. There is no substantial interaction of the unpaired electron with transannular protons.     

Synthesis of o-benzoquinones derived from [2.2]- and [3.3]paracyclophanes

Oxidation of [2.2]- and [3.3]paracyclophanols with benzeneseleninic anhydride readily afforded the corresponding cyclophane-o-quinones which showed the intramolecular charge-transfer interactions.     

Synthesis,Structure, and Biological Activity of [2.2]Paracyclophane Derivatives. 8. α-Pyridyl([2.2]paracyclophan-4-yl)-phenylmethanol: Structure of the Complex with Cu(II) Chloride and Intramolecular Cyclization

The reaction of 2-benzoylpyridine with 4-([2.2]paracyclophanyl)lithium or of 4-benzoyl[2.2]paracyclophane with 2-pyridyllithium gave α-pyridyl([2.2]paracyclophan-4- yl)phenylmethanol. X-ray analysis has been used to study the molecular and crystalline structure of its complex with Cu(II) chloride. It was found that this triaryl-substituted methanol undergoes an intramolecular cyclocondensation in refluxing formic acid and involves the pyridine ring and the cyclophane substituent. Heterocyclization at the ortho-position of the latter gives 10-phenyl[2.2]paracyclophano[4,5-b]indolizine and cyclization at the pseudo-gem-position the 1-phenyl-1,1a-dehydro-6-aza[3.2.2](1,2,5)-6H-cyclophano[1,2-a]pyridine. The compounds prepared have luminescent properties. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 864–873, June 2005.     

Substituted 2- and 4-benzylpyridines in the synthesis of benzo[g]quinolines and benzo[g]isoquinolines

Nitrogen-containing heterocyclic analogs of anthracene, viz., benzo[g]isoquinolines and benzo[g]quinolines, were obtained by dehydrocyclization on a K-16 catalyst of mixtures of methyl-substituted 2- and 4-benzylpyridines with methyl groups in various positions of the pyridine and benzyl rings, which are formed by benzylation of -picoline, as well as pyridine, by the Ladenburg method. The spectral characteristics of the synthesized compounds are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 673–676, May, 1980.     

Synthesis of novel mono- and diaryl-substituted [2.2]paracyclophanes

The cross-coupling reactions of 4-bromo[2.2]paracyclophane withp-tolylmagnesium bromide in the presence of various palladium and nickel complexes have been studied. It was found that [1,1 -bis(diphenylphosphinoferrocene)]palladium dichloride (PdCl₂ · dppf) shows the highest catalitic activity in this reaction. A series of new mono- and diaryl [2.2]paracyclophane derivatives with various substituents in the arene ring have been synthesized using this catalyst. It was shown that it is possible to cross-couple organozinc [2.2]paracyclophane derivatives with aromatic bromides. The composition and structure of the compounds obtained have been established on the basis of elemental analysis and spectral data. Some correlations between the structure and spectral parameters of mono- and diarylsubstituted [2.2]paracyclophanes have been found.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1081–1085, June, 1994.The present work was financially supported by the Russian Foundation for Basic Research (Project No. 93-03-5246).The authors wish to express their gratitude to Prof. N. A. Bumagin for his scientific interest and helpful discussions.     

Synthesis of benzo[g]quinoline derivatives. XI. 2,4-Diamino-substituted benzo[g]quinolines

Previously unknown 2,4-diamino-substituted benzo[g]quinolines were synthesized from 2,4-dihydroxybenzo[g]quinoline.     

Syntheses of 4-(benzo[b]furan-2 or 3-yl)- and 4-(benzo[b]-thiophen-3-yl)piperidines with 5-HT2 antagonist activity

The syntheses of 4-(benzo[b]furan-3-yl)piperidines, 4-(benzo[b]furan-2-yl)piperidines and 4-(benzo[b]thiophen-3-yl)piperidines with 5-HT₂ antagonist activity are described. Reaction of 1-acetyl-4-(2,4-difluorobenzo-yl)piperidine 2 with methyl glycolate gave methyl 6-fluoro-3-(1-acetylpiperidin-4-yl)benzo[b]furan-2-carboxylate 3 , which was converted to 2-[2-[4-(benzo[b]furan-3-yi)piperidin-1-yl]ethyl-5,6,7,8-tetrahydro-1,2,4-triazolo-[4,3-a]pyridin-3(2H)-one hydrochloride 9 . Analogous benzo[b]furans 17a-d and benzo[b]thiophenes 10a,b and 18a were prepared by a similar method. Cyclization of 4-fluoro-2-(4-pyridinylmethoxy)acetophenones 20a,b afforded 4-(benzo[b]furan-2-yl)pyridines 21a,b , which were converted to 2-[2-[4-(benzo[b]furan-2-yl)-piperidin-1-yl]ethyl-5,6,7,8-tetrahydro-1,2,4-triazolo[4,3-a]pyridin-3(2H)-one hydrochlorides 24a,b. Among them, benzo[b]furans 9 and 17a,d and benzo[b]thiophenes 10 and 18a showed potent 5-HT₂ antagonist activity in vitro.     

Synthesis and structure of [2.2]paracyclophanes incorporating alkyne units in the extended linear chain

The novel [2.2]paracyclophanes 4-7 with an extended π-conjugation due to the presence of a linear arylethynyl chain have been synthesized by the Pd-catalyzed Sonogashira coupling reaction.     

Synthesis of regioisomeric 6,9-(chlorofluoro)-substituted benzo[g]quinoline-5,10-diones,benzo[g] isoquinoline-5,10-diones and 6-chloro-9-fluorobenzo[g]quinoxaline-5,10-dione

Treatment of difluoro or chloro fluoro-substituted benzyl bromides 5a-c with zinc dust in tetrahydro-furan leads to the corresponding benzylic zinc bromides 6a-c. These organometallics on treatment with chlorosubstituted heterocyclic esters 4A and 4B mediated by nickel catalysis undergo couplings to yield dihalobenzyl substituted heterocyclic esters 7Aa-c and 7Ba-c. Treatment of 4c with 6c under Pd catalysis leads to 7Cc. The acids 8, prepared by hydrolysis of these esters, with treatment of fuming sulfuric acid undergo cyclizations and oxidations to yield the desired regioisomeric dihalo-substituted heterocyclic quinones 2.     

Synthesis of benzo[g]quinoline derivatives. XII. 1,2,3,4-Tetrahydro-4-oxo-10-chlorobenzo[g]quinoline

1,2,3,4-tetrahydro-4-oxobenzo[g]quinoline was halogenated with elementary chloride. The structure of the product — 1,2,3,4-tetrahydro-4-oxo-10-chlorobenzo[g]quinoline — was established by alternative synthesis.     

A selective synthesis of 2-([2,2]paracyclophan-5-yl)pyrrole from 5-acetyl[2,2]paracyclophane via the Trofimov reaction

Rearrangement of 5-(1-vinyloxyiminoethyl)[2,2]paracyclophane, the key intermediate of the Trofimov reaction (pyrrole formation from ketoximes and acetylene), gives (120 °C, 30 min, DMSO) 2-([2,2]paracyclophan-5-yl)pyrrole in 74% yield. The intermediate 5-(1-vinyloxyiminoethyl)[2,2]paracyclophane has been synthesised in 78% yield by vinylation of the Cs-derivative of the oxime of 5-acetyl[2,2]paracyclophane with acetylene under pressure in the DMSO-n-pentane two-phase system (70 °C, 5 min).     

Synthesis of 2-(pyrimidin-4-yl)indoles

The synthesis of 2-substituted isomers of the meridianins, a familiy of bioactive indole alkaloids isolated from the tunicate Aplidium meridianum, was undertaken. The synthetic route comprises six steps, with a microwave promoted Fischer cyclization as the key reaction.     

Synthesis,spectral and electrochemical properties of halogenated 6-alkyl-5-aryl-1-(benzo[d]thiazol-2-yl)-3-phenylverdazyls and 5-aryl-1-(benzo[d]thiazol-2-yl)-3-phenyl-6-vinylverdazyls

Chemistry of Heterocyclic Compounds - A sequence of alkylation, cyclization, and oxidation reactions was used to convert 5-aryl-1-(benzo[d]thiazol-2-yl)-3-phenylformazans into...     

Synthesis of helical [2.2]paracyclophanes containing carbocyclic and heterocyclic five-membered rings

The preparation of a [2.2]indenoparacyclophane-based diene is described. Diels-Alder cycloadditions of this diene with N-methylmaleimide, N-phenylmaleimide and maleic anhydride occurred in good yields and anti-diastereoselectively only under high pressure conditions. Heterohelicenophanes were prepared by dehydrogenation of the Diels-Alder products with 10% Pd/C catalyst. A new helicenophanequinone was obtained by the reaction between the diene and 1,4-naphthoquinone.     

Structure and NMR spectra of some [2.2]paracyclophanes. The dilemma of [2.2]paracyclophane symmetry

Density functional theory (DFT) quantum chemical calculations of the structure and NMR parameters for highly strained hydrocarbon [2.2]paracyclophane 1 and its three derivatives are presented. The calculated NMR parameters are compared with the experimental ones. By least-squares fitting of the (1)H spectra, almost all J(HH) coupling constants could be obtained with high accuracy. Theoretical vicinal J(HH) couplings in the aliphatic bridges, calculated using different basis sets (6-311G(d,p), and Huz-IV) reproduce the experimental values with essentially the same root-mean-square (rms) error of about 1.3 Hz, regardless of the basis set used. These discrepancies could be in part due to a considerable impact of rovibrational effects on the observed J(HH) couplings, since the latter show a measurable dependence on temperature. Because of the lasting literature controversies concerning the symmetry of parent compound 1, D(2h) versus D(2), a critical analysis of the relevant literature data is carried out. The symmetry issue is prone to confusion because, according to some literature claims, the two hypothetical enantiomeric D(2) structures of 1 could be separated by a very low energy barrier that would explain the occurrence of rovibrational effects on the observed vicinal J(HH) couplings. However, the D(2h) symmetry of 1 with a flat energy minimum could also account for these effects.     

DFT study of [2.2]-, [3.3]-, and [4.4]paracyclophanes: strain energy, conformations, and rotational barriers

The three smallest symmetrical paracyclophanes, having tethers with two, three, or four methylene groups, have been examined with four density functional methods (B3LYP, M06-2x, B97-D, ωB97X-D). The geometries predicted by functionals accounting for medium-range correlation or long-range exchange and/or dispersion are in close agreement with experiment. In addition, these methods provide similar estimates of the strain energy of the paracylcophanes, which decrease with increasing tether length. [4.4]Paracyclophane is nearly strain-free, reflecting the small out-of-plane distortion of its phenyl rings. Lastly, the barrier for interconversion of the conformers of [3.3]paracylcophane is computed in close agreement with experiment, and an estimate for phenyl rotation in [4.4]paracyclophane of about 19 kcal mol(-1) is predicted by the DFT methods employed.     

Design,Synthesis, and Biological Evaluation of Novel 2-(4-Arylsubstituted-1H,2,3-triazol-1-yl)-N-{4-[2-(thiazol-2-yl)benzo[d]thiazol-6-yl]phenyl}acetamide Derivatives as Potent Anticancer Agents

Russian Journal of General Chemistry - A novel series of benzothiazole bearing 1,2,3-triazole derivatives 11a–11j are synthesized, and their structures are confirmed by 1H and 13C NMR, and...     

Diazabicycloalkanes with nitrogen atoms in the nodal positions. 6. Synthesis and some properties of benzo[f]-1,5-diazabicyclo[3.2.2]nonene and benzo[g]-1,6-diazabicyclo[4.2.2]decene

The reaction of N-acetyl derivatives of N,N-trimethylene- and N,N-tetramethylene-o-phenylenediamines with ethylene oxide gave the corresponding N-(-hydroxyethyl)-N-acetyl derivatives, the cyclization of which in refluxing hydrobromic acid leads to benzo[f]-1,5-diazabicyclo[3.2.2]nonene and benzo[g]-1,6-diazabicyclo[4.2.2.]decene.See [1] for Communication 5.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1538–1542, November, 1981.