Linear Annulation Research Articles

How π Extension or Structural Bending Alters the Properties of Boron-Doped Phenylene-Containing Oligoacenes

Linear annulation of two 2,3-biphenylenediyl moieties to a 1,4-dibora-2,5-cyclohexadiene core via its carbon atoms leads to the boron-doped phenylene-containing oligoacene (B-POA) DBI. The optoelec...

Crystal structure of 12-benzyl-sulfanyl-2,9-di-bromo-6H-dibenzo[b,g][1,8]naphthyridin-11-one.

The hetero­tetra­cene skeleton of the title mol­ecule, C23H14Br2N2OS, is defined by linear annulation of four six-membered rings, including two N heteroatoms. This moiety is nearly planar (r.m.s. deviation = 0.055 Å), with a slight twist of 4.1 (2)° between the two halves of the aromatic system. The dihedral angle between the least-squares plane of the skeleton and the benzyl group is 24.5 (3)°; the C—S—C angle involving the benzyl­sulfanyl group is 99.2 (4)°. In the crystal, mol­ecules are π-stacked in an anti­parallel fashion along [110], with a distance between the aromatic planes of 3.47 (2) Å. Inter­molecular N—H⋯O hydrogen bonds form chains extending parallel to [001] and bridge the anti­parallel inter­digitated stacks of mol­ecules.

Synthesis of benzo-annulated tryptanthrins and their biological properties

A series of benzo-annulated derivatives of tryptanthrin were prepared and their optical and redox properties were studied. Tryptanthrin and its benzo-annulated derivatives showed selective inhibitory activity on topo I with an increase of activity on topo II by benzo-annulation on quinazolin-4(3H)-one moiety. Although the benzo-annulation on quinazolin-4(3H)-one ring did not affect significantly on the inhibitory activities against topo I and II, the benzoannulation on indolin-3-one ring affected the inhibitory activity very much especially by linear annulation. Cytotoxicities were not significantly changed upon benzoannulation, which were not directly related either to the inhibitory activities against topo I and II or to the reduction potentials.

Investigations into the Regioselectivity of Fischer Indole and Friedländer Quinoline Syntheses with Octahydroisobenzofuran and Octahydroisoindole Derivatives

A Fischer indole synthesis with a cis-configurated octahydroisobenzofuran-6-one yielded exclusively a furo[3,4-c]carbazole derivative as the product of a regioselective angular annulation reaction. A Friedländer quinoline synthesis from the same substrate gave a mixture of angular and linear annulation products, i. e. furo[3,4-a]acridine and furo[3,4-b]acridine derivatives. When submitting a mixture of cis- and trans-octahydroisoindole derivatives to Fischer and Friedländer syntheses, the trans-starting material gave regioselectively linear annulation products, i. e. pyrrolo[3,4-b]carbazole and pyrrolo[3,4-b]acridine derivatives. In contrast, the respective cis-configurated isoindole gavemixtures of angular and linear annulation products. The constitutions and relative configurations of nine new indole and quinoline derivatives were established by 2D NMR experiments and X-ray singlecrystal investigations.

Novel [6]‐ and [7]Helicene‐Like Quinones via Mono‐ and Bidirectional Chromium‐Templated Benzannulation of Bridged Binaphthyl Carbene Complexes

AbstractA new organometallic approach to novel, functionalised, helicene‐like quinones and bisquinones has been developed based on the chromium‐templated [3+2+1] benzannulation reaction. The [5]helicene‐analogous monocarbene chromium complexes 4, 5, 17 and 19, derived from dibromo‐substituted methylene‐ or silylene‐tethered binaphthols 2 and 3, react with various alkynes to give [6]helicene‐like quinones 6–13 and 20–29 after oxidative work‐up. A rare competition of angular vs. linear annulation is observed for the incorporation of phenylacetylene that affords quinones 21/22 and 28/29. Protection of the phenolic benzannulation product with camphanic acid chloride 14, followed by chromatographic separation, provides access to enantiopure [6]helicene‐like derivatives. Bidirectional benzannulation of helical biscarbene complexes 16 and 18 results in bisangular and angular‐linear bisquinones 30–36 after oxidative work‐up. X‐ray crystal structures of the heterocyclic [5]‐, [6]‐ and [7]helicene‐derivatives and the angular‐linear annulation products indicate an increasing distortion of the helical framework with progressive annulation. The CD spectra of the methylene‐tethered biaryls (3, 9, 14, 36) reflect the different interactions between the aryl chromophores; cyclovoltammetric studies of bisangular bisquinones 30 and 33 reveal three reversible, one‐electron reduction steps. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

A Novel Approach to Functionalized Heterohelicenes via Chromium-Templated Benzannulation Reactions

A series of functionalized oxa- and thiaheterohelicenes has been prepared by a new progressive annulation technique based on the chromium-templated [3+2+1]benzannulation reaction of hetero[5]helicene carbene complexes with various alkynes partly in competition of angular and linear annulation. Oxidative work-up with CAN yields the respective quinones along with small amounts of nitrated products or a nitrate ester byproduct. Thermal recomplexation of an acylated monobenzannulation product by Cr(CO)6 affords the corresponding, thermodynamically favored η6-oxa[6]helicene-Cr(CO)3 complex. Bidirectional benzannulation reveals a more delicate regioselectivity and yields three different isomers including a bisquinone with an unprecedented bislinear annulation pattern. Molecular structures determined by X-ray analysis indicate a decreasing helical distortion as a result of progressive annulation, steric demand of the quinone substitution pattern (Ph>Pr>Et), or the nature of the embedded heterocycle (SO2>S>O).

Synthesis of modified psoralen analogues

Substituted 3-(5-methyl-7-oxofuro[3,2-g]chromen-6-yl)propanoic acids analogous to psoralen were synthesized by linear annulation of a furan moiety to the coumarin system. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 3; see also http://www.maik.ru.

Reactions of complex ligands: Part 94. Chromium-templated angular versus linear benzannulation of dibenzofuran and haptotropic metal migration in tetracyclic fused arenes

The chromium-templated [3+2+1]-benzannulation of dibenzofuryl(methoxy)carbene complex 1 with alkynes leads to hydroquinoid benzonaphthofurans. A competition of angular versus linear annulation affords angular-fused (η 6-1,2,3,4,4a,11c)-benzo[ b]naphtho[1,2- d]furan tricarbonyl chromium complexes 2– 6 along with considerable amounts of uncoordinated benzo[ b]naphtho[2,3- d]furans as linear annulation products 7– 9. As demonstrated for 2 and 6 the Cr(CO) 3 complexes undergo a thermally induced haptotropic metal migration along the tetracyclic heteroaromatic π-system to give (η 6-7a,8,9,10,11,11a)-benzonaphthofuran complexes 10 and 11 in which the chromium fragment is coordinated to the terminal unsubstituted benzoid ring. The molecular structures of both the kinetic annulation products and the thermodynamic rearrangement products were established by NMR spectroscopy and single crystal X-ray analysis.

Synthesis and Characterization of Tetra(tert-butyl)-2,3-anthracenocyaninatoiron(II) Compounds

Abstract Bis(isocyanide) and bis(pyridine) complexes of tetra(tert-butyl)-2,3-anthracenocyaninatoiron(II) were synthesized from 6-tert-butyl-2,3-dicyanoanthracene and characterized by UV/Vis, NMR, and Mössbauer spectroscopy. Linear annulation of benzene rings to the phthalocyanine macrocycle produces a bathochromic shift of the Q-band. The first oxidation potential of the 2,3-anthracenocyanine macrocycle determined by cyclic voltammetry is lower than that of 2,3-naphthalocyanine.

Synthese von Imidazo- und Diimidazo[1,2,4,5]tetrazinen; zur Tautomerie von Dihydro-1,2,4,5-tetrazinen

Synthesis of Imidazo- and Diimidazo[1,2,4,5]tetrazines; For Tautomerism of Dihydro-1,2,4,5-tetrazines Dimethyl 1,4-dihydro-1,2,4,5-tetrazine-3,6-dicarboxylate (1) reacts with isocyanates to afford the 2,7-disubstituted 1H6H -diimidazo[1,5-b: 1′,5′-e] [1,2,4,5]tetrazine-1,3,6,8(2H,7H)-tetrones 2a-m, a hitherto unknown ring system. The linear annulation of 2m was established by X-ray analysis, and as a consequence the 1,4-dihydro tautomer found to be the main constituent of all other potential isomers. Compound 1 reacts with isothiocyanates to give the corresponding 1,6-dithioxo derivatives 5a,b as well as the 7-substituted methyl 2,6,7,8-tetrahydro-8-oxo-6-thioxoimidazo[1,5-b] [1,2,4,5]tetrazine-3-carboxylates 6b,c respectively, while the unsymmetrically substituted 2-tert-butyl-7-(4-chlorophenyl)-6-thioxo-1H, 6H-diimidazo[1,5-b: 1′,5′-e] [1,2,4,5]tetrazine-1,2,8-(2H,7H)-trione (8) is obtained from 6c and the corresponding isocyanate.

A convenient generation of 2,3-naphthalyne. Linear annulation of naphthalene and a new naphthacene synthesis

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA convenient generation of 2,3-naphthalyne. Linear annulation of naphthalene and a new naphthacene synthesisCraig S. LeHoullier and Gordon W. GribbleCite this: J. Org. Chem. 1983, 48, 14, 2364–2366Publication Date (Print):July 1, 1983Publication History Published online1 May 2002Published inissue 1 July 1983https://doi.org/10.1021/jo00162a013RIGHTS & PERMISSIONSArticle Views911Altmetric-Citations33LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (404 KB) Get e-Alerts Get e-Alerts