Approaches to the synthesis of benzo[c]phenanthridines

6-Methylbenzo[c]phenanthridine derivatives were synthesized via an established route and their cytotoxic activity determined. Attempts to synthesize benzo[c]phenanthridines lacking the 6-methyl group via a 2-ben-zopyrylium intermediate were unsuccessful.     

Synthesis and spectroscopic properties of novel benzo[a]phenanthridines

Condensation of arylidene-2-naphthylarnines with 5,5-dimethylcyclohexane-1,3-dione (dimedone) gives novel 2,2-dimethyl-5-R-1,2,3,4,5,6-hexahydrobenzo[a]phenanthridin-4-ones. Treatment of azomethines containing an ortho hydroxyl group in the aldehyde fragment gives the corresponding 3,3,6,6-tetramethyl-9-R-1,2,3,4,5,6,7,8-octa-hydroxanthene-1,8-diones. The IR, UV, PMR, and mass spectra of the compounds synthesized have been studied.     

A comprehensive study of isoskeletal analogs of dibenzo[a,c]anthracene

While reviewing the chemistry of cyclopentadienone derivatives and aza isoskeletal analogs of dibenzo[a,c]anthracene, additional molecular orbital (MO) and spectroscopic results and insights are presented. The MO tendency for coplanarity of phenyl substituents on benzenoids is demonstrated. Perpendicularly oriented phenyl substituents resulting from steric interactions strongly shield appropriately situated protons in NMR spectra. The principles of alternating polarity and parallel correspondence in conjunction with MO methods are used to relatively order aza arene isoskeletal analogs according to their chemical properties. Since less than 1.87% of the isoskeletal analogs of benzo[a,c]-anthracene have been reported, this summary work will help one to forecast the major chemical properties of those not yet synthesized.A preliminary account of this work was presented at the 23rd ACS Midwest Regional Meeting, University of Iowa, Iowa City, Nov. 17, 1988     

Syntheses of dibenzo[c,e][1,2]diselenin and related novel chalcogenide heterocyclic compounds

Reaction of 2,2′-dilithio-1,1′-binaphthyl with selenium followed by air oxidation gives a mixture of dinaph-thoselenophene and dimer and oligomers of 2,2′-diseleno-1,1′-binaphthyl. 2,2′-Dilithio-1,1′-biphenyl reacts with selenium to afford dibenzo[c,e][1,2]diselenin. Structures of the dimeric 2,2′-diseleno-1,1′-binaphthyl and dibenzo[c,e][1,2]diselenin have been confirmed by X-ray crystallographic analyses. Similar reaction of 2,2′-dilithio-1,1′-binaphthyl with sulfur or tellurium gives a mixture of dinaphthothiophene and dinaphtho[2,1-c:-1′,2′-e][1,2]dithiin or a mixture of dinaphthotellurophene and oligomer of 2,2′-ditelluro-1,1′-binaphthyl, respectively. Dibenzotellurophene and oligomer of 2,2′-ditelluro-1,1′-biphenyl are obtained from reaction of 2,2′-dilithio-1,1′-biphenyl with tellurium.     

Nickel-catalyzed regioselective access to dibenzo[c,f]oxocine framework via reductive Heck reaction

Nickel-catalyzed regioselective construction of dibenzo[c,f]oxocine framework with tri-substituted exo-cyclic alkenes have been obtained through an efficient implementation of reductive-Heck protocol. This cost effective, efficient methodology has been demonstrated for the synthesis of various dibenzo[c,f]oxocine derivatives with moderate to good yields.     

Synthesis and physicochemical characterization of novel 6-aminopyrido[3,4-c][1,9]phenanthrolines as aza-analogs of benzo[c]phenanthridines

Based on the 6-aminobenzo[c]phenanthridines, a compound class showing noteworthy antitumor activity, an efficient one-step synthesis consisting of a base-catalyzed condensation of 2 equiv of 4-methylpyridine-3-carbonitrile and various aldehydes causing twofold ring closure is described. The obtained 6-amino-11,12-dihydropyrido[3,4-c][1,9]phenanthrolines could be aromatized with Pd/C at high temperatures to form 6-aminopyrido[3,4-c][1,9]phenanthrolines. All compounds were systematically characterized regarding both lipophilicity and solubility and a high cytotoxic potential was evaluated in preliminary in vitro studies. Compared to formerly described 6-aminobenzo[c]phenanthridines our newly developed phenanthrolines turned out to possess improved drugability, due to significantly increased water-solubility and decreased lipophilicity.     

Spectroscopic and electrochemical properties of cyclopalladated complexes based on dibenzo[a,c]phenazine

Cyclopalladated complexes based on dibenzo[a,c]phenazine were studied by ¹H NMR and electronic absorption and emission spectroscopy, and cyclic voltammetry. Replacement of ethylenediamine by heterocyclic ligands scarcely affects the coordination-induced proton shifts of the diazine part of the cyclometalated ligand, but, as the basicity of chelated ligands decreases, the screening of protons of the carbanionic part of those cyclometalated ligands which is the most proximate to the coordination center regularly decreases. Cyclopalladation reveals itself in the following characteristic parameters of photo-and electro-induced electron-transfer processes: longwave absorption band, λ_max (437±7) nm and ε (3.0±1.5) × 10³ l mol^?1 cm^?1, vibration-structured low-temperature luminescence resulting from spin-forbidden optical transition from the excited to ground state of the complex with the energy E ^∞ (16.98±0.03) kK and the lifetime τ (190±20) μs, and reversible one-electron electroreduction wave with E _1/2 ?(1.39±0.03) V.     

Novel domino oxidative coupling: C-C bond formation sequence to highly functionalized dibenzo[a,c]cycloheptenes

A domino sequence involving various MoCl(5)-mediated oxidations followed by trapping and supposed [3,3]-sigmatropic rearrangement provides a fast access to the full carbon skeleton of metasequirin-B. A variety of different moieties R(1) and R(2) are tolerated.     

Synthesis of polyoxygenated dibenzo[a,e]cycloheptatrienes

A successive route for the synthesis of substituted dibenzo[a,e]cycloheptatriene 1 was established by the reduction of 2-allylbenzaldehyde 4, the BF₃·OEt₂-mediated intermolecular coupling of 2-allylphenylmethanol 5 with oxygenated benzenes 6, the olefinic oxidative cleavage of 7 and the intramolecular ring-closure of 8. Functionalized anthracene 13 were prepared from 2-vinylbenzaldehyde 9. The key structures were confirmed by X-ray single crystal diffraction analysis.     

New reactions of a dibenzo[a,e]pentalene

Reduction of dibenzo[a,e]pentalene 3 (denoted as dibenzopentalene hereafter) with excess lithium gave dilithium dibenzopentalenide 1. Since oxidation of 1 with iodine gave 3, redox behavior between 1 and 3 is controllable and reversible. Reaction of 3 with methyllithium gave lithium 5-methyldibenzopentalenide 5, the formation of which was evidenced by some trapping experiments and X-ray crystallographic analysis. Reactions of 3 with halogens gave 5,10-dihalodibenzopentalenes, 8 and 9. Some optical properties of novel dibenzopentalene derivatives are also demonstrated.     

Synthesis of 5-Aryl-1,2,3,4-tetrahydrobenzo[a]phenanthridines

Previously unknown derivatives of tetrahydro[a]phenanthridine containing annelated benzoquinoline and cyclohexene nuclei were prepared by condensation of azomethines of the 2-naphthylamine series with cyclohexanone. The possibility of synthesis of such compounds without preliminarily preparing Schiff bases was demonstrated. The effect of substituents in the aromatic ring of the azomethine on the yield of the target products was elucidated. The IR, UV, ¹H NMR, and mass spectra of the synthesized compounds were discussed.     

Functionalized derivatives of dibenzo [c,j] dipyrazolo-[3,4-f∶3′,4′-m] [1,2,5,8,9,12] hexaazacyclotetradecinate

A number of derivatives of dibenzo [c,j] dipyrazolo [3,4-f3,4-m] [1,2,5,8,9,12]-hexaazacyclotetradecinate with peripheral nitro, amino, and acetylamino groups have been synthesized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 106–114, January, 1984.     

Dihydrodiols and diol epoxides of dibenzo[a,i]-and [a,h]pyrene

Syntheses of dihydrodiols and highly mutagenic diol epoxides of the carcinogenic polycyclic aromatic hydrocarbons dibenzo[a,i]-and [a,h]pyrene are described.     

The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 22 Dibenzo[f,h]benzothieno[2,3‐c]quinoline,dibenzo[f,h]benzothieno[2,3‐c][1,2,4]triazolo[4,3‐a]quinoline and dibenzo[f,h]naphtho[2′,1′:4,5]thieno[2,3‐c]quinoline

Photocyclization of 3‐chloro‐N‐(9‐phenanthryl)benzo[b]‐thiophene‐2‐carboxamide ( 3 ) and 3‐chloro‐N‐(9‐phenanthryl)‐naphtho[1,2‐b]thiophene‐2‐carboxamide ( 10 ) yielded dibenzo[f,h]benzothieno[2,3‐c]‐quinolin‐10(9H)‐one ( 4 ) and dibenzo[f,h]naphtho[2′,1′:4,5]thieno[2,3‐c]quinolin‐10(9H)‐one ( 11 ), respectively. Further elaboration of the lactams provided three novel unsubstituted new ring systems.     

Anti-cancer activity of novel dibenzo[b,f]azepine tethered isoxazoline derivatives

Background  

Nef is an HIV-1 accessory protein essential for viral replication and AIDS progression. Nef interacts with a multitude of host cell signaling partners, including members of the Src kinase family. Nef preferentially activates Hck, a Src-family kinase (SFK) strongly expressed in macrophages and other HIV target cells, by binding to its regulatory SH3 domain. Recently, we identified a series of kinase inhibitors that preferentially inhibit Hck in the presence of Nef. These compounds also block Nef-dependent HIV replication, validating the Nef-SFK signaling pathway as an antiretroviral drug target. Our findings also suggested that by binding to the Hck SH3 domain, Nef indirectly affects the conformation of the kinase active site to favor inhibitor association.     

Mass spectral fragmentation mechanisms of some dibenzo[c,f][1,2] diazepines

The fragmentation mechanisms of 11H-dibenzo[c,f][1,2]diazepine (I), its 3,8-dichloro derivative (II), 3,8-dichlorodibenzo[c,f] [1,2]diazepin-11-one (III) and 3,8-dichloro-11H-dibenzo-[c,f][1,2]diazepin-N-oxide (IV) are discussed. The initial loss of molecular nitrogen is characteristic of I, II and III. Compound IV has a strong molecular ion, that competitively eliminates cither NO or Cl- and N₂O. The common radical ion, m/166 e present in the mass spectra of I, fluorene, 2-methyl-9,10-anthraquinone and 2-methylbenzo[c]cinnoline, appears to be formed in different states.     

Intramolecular Diels-Alder reaction of 1-aminoisobenzofurans: Application to the synthesis of benzo[c]phenanthridines

Intramolecular Diels-Alder reactions of 1-aminoisobenzofurans give benzo[c]phenanthridines. The reactive intermediates are generated from o-(diazomethyl)benzamides.     

螺[二苯并[a,j]氧杂蒽-14,9'-芴]的合成及性质

芴酮与2-萘酚在硫酸和3-巯基丙酸的作用下反应得到化合物螺[二苯并[a,j]氧杂蒽-14,9'-芴]. 采用核磁共振、 质谱、 红外光谱和元素分析等对该化合物进行了表征, 并通过X射线衍射法测得了其晶体结构, 确定该化合物是通过二苯并[a,j]氧杂蒽中的含氧六元杂环和芴中的五元环共用一个碳原子形成一个螺环. 利用荧光光谱和热分析等手段对该化合物的性质进行了研究, 结果表明其最大荧光发射峰为366 nm, 熔点为297 ℃, 热分解温度为329 ℃, 具有较高的热稳定性.