Synthesis of Pyridophenanthrolines via a Three‐Component Reaction Involving 1,10‐Phenanthrolin‐5‐Amine

A facile and efficient method for the synthesis of benzo[b ]pyrido[3,2‐f ][1,7]phenanthrolines and dipyrido[4,3‐b :3′,2′‐f ][1,7]phenanthrolines has been developed in high yields. Using EtOH as a solvent without any additionally basic catalysts, the three‐component reaction of aromatic aldehyde, 1,10‐phenanthrolin‐5‐amine, and dimedone or piperidine‐2,4‐dione affords two novel classes of fused phentacyclic heterocycles containing both pyridine and phenanthroline moieties.     

Synthesis, characterization and interaction with DNA of ruthenium(II) mixed-ligand complexes containing pyridino[3,2-f] [1,7]phenanthroline

Summary A series of new complexes [RuL₂(pdphen)]²⁺, where pdphen is the planar ligand pyridino[3,2-f] [1,7]phenanthroline and L = 2,2-bipyridine, phenanthroline, 2,9-dimethylphenanthroline or 5-nitrophenanthroline, were prepared and characterized. The binding of [RuL₂-(pdphen)] ²⁺ to calf thymus DNA was investigated using absorption, fluorescence and circular dichroism (c.d.) spectroscopies. All of the complexes show absorption hypochromicity associated with binding to calf thymus DNA. [Ru(bipy)₂pdphen]²⁺ and [Ru(phen)₂pdphen]²⁺ also show fluorescence intensities and excited state life-time increases. The c.d. spectra of dialyzates from solutions of racemic complexes versus calf thymus DNA indicate enantioselectivity associated with binding to DNA.     

Bis(4,4′‐dimethyl‐2,2′‐bipyridine) ruthenium (II) Complexes Containing 2‐Arylimidazo‐ [4,5‐f] [1,10] phenanthroline: Syntheses,Characterization and Third‐order Nonlinear Optical Properties

Four novel mononuclear ruthenium(II) complexes [Ru(dmb)₂L]²⁺ [dmb = 4,4′‐dimethyl‐2,2′‐bipyridine, L = imidazo‐[4,5‐f][1,10]phenanthroline (IP), 2‐phenylimidazo‐[4,5‐f][1,10]phenanthroline (PIP), 2‐(4′‐hydroxyphenyl)imidazo‐[4,5‐f] [1,10] phenanthroline (HOP), 2‐(4′‐dimethylaminophenyl) imidazo‐[4, 5‐f] [1,10] phenanthroline (DMNP)] were synthesized and characterized by ES‐MS, ¹H NMR, UV‐vis and electrochemistry. The nonlinear optical properties of the ruthenium(II) complexes were investigated by Z‐scan techniques with 12 ns laser pulse at 540 nm, and all of them exhibit both nonlinear optical (NLO) absorption and self‐defocusing effect. The corresponding effective NLO susceptibility |x³| of the complexes is in the range of 2.68 × 10^?12‐4.57 × 10^?12 esu.     

Synthesis of 2H‐chromeno[4,3‐b]pyridine‐2,5(1H)‐diones and related heterocycles via the erlenmeyer‐ploechl reaction

1,2‐Dihydro‐5H‐[1]benzopyrano[4,3‐b]pyridine‐2,5‐diones 4a‐j were synthesized from 4‐alkylamino‐coumarin‐3‐carbaldehydes 1 and 5(4H)‐oxazolinones (azalactones) derived from N‐acetylglycine ( 2a ) and hippuric acid ( 2b ). The intermediates 3 ( 3j isolated only) underwent spontaneous recyclization via opening of the azalactone and successive formation of the fused 2‐pyridones 4 . Attempts to synthesize the selected 2H‐chromeno[3,4‐f]‐1,7‐naphthyridine 6 by Vilsmeier reaction of 4e failed. Instead, N‐deacetylation took place, followed by formylation of the amino group to the formamidine 7a . In addition, pyranopyridine 9a was obtained by condensation of the 3‐formyl‐2‐pyridone 8 with the azalactone derived from 2a and acetic anhydride.     

Synthesis of some novel derivatives of 1,10‐phenanthroline

The synthesis is described of a set of new N‐heterocyclic compounds which are derivatives of 1,10‐phenanthroline. The compounds are designed to be general purpose chelating agents which could function as tri‐, tetra‐ or hexadentate ligands with transition metal ions. Fused‐ring molecular components have been included in the design of the compounds so that they may function as binding agents to DNA through intercalation. This includes the synthesis of substituted derivatives of pyrazino[2,3‐f][1,10]phenanthroline and dipyrido[3,2‐a:2′3′‐c]phenazine.     

New Resveratrol Oligomers from the Stem Bark of Hopea hainanensis

Three new resveratrol oligomers, hopeahainanphenol ( 1 ), neohopeaphenol A ( 2 ), and neoisohopeaphenol A ( 3 ), were isolated from the stem bark of Hopea hainanensis (Dipterocarpaceae). Their structures were elucidated by in‐depth spectroscopic analyses, including 1D‐ and 2D‐NMR techniques, and by HR‐ESI‐MS. All the three phytochemicals were tested in vitro for acetylcholinesterase (AChE) inhibitory and antitumor activity. The dimeric compound 2 , which corresponds to (1S*,6S*,7S*,11bS*)‐1,6,7,11b‐tetrahydro‐1,7‐bis(4‐hydroxyphenyl)‐6‐[(1R*,6R*,7R*,11bR*)‐1,6,7,11b‐tetrahydro‐4,8,10‐trihydroxy‐1,7‐bis(4‐hydroxyphenyl)benzo[6,7]cyclohepta[1,2,3‐cd]benzofuran‐6‐yl]benzo[6,7]cyclohepta[1,2,3‐cd]benzofuran‐4,8,10‐triol, was found to be significantly active against AChE, with an IC₅₀ value of 7.66 ± 0.13 μm.     

Pt(II) complexes immobilized on polymer‐modified magnetic carbon nanotubes as a new platinum drug delivery system

We combine nanotechnology and chemical synthesis to create a novel multifunctional platinum drug delivery vehicle based on magnetic carbon nanotubes (multiwall carbon nanotubes/Fe₃O₄@poly(citric acid)/cis‐[(Pt(1,7‐phenanthroline)(DMSO)Cl₂)]‐b‐poly(ethylene glycol) (MCNTs/FO@PC/Pt(II)‐b‐PEG)) for targeted cancer therapy. MCNTs/FO@PC/Pt(II)‐b‐PEG was conveniently prepared by conjugating cis‐[Pt(1,7‐phenanthroline)(DMSO)Cl₂] complex to MCNTs/FO@PC‐b‐PEG via strong hydrogen‐bonding interactions. In comparison with free cisplatin and Pt(II) complex, MCNTs/FO@PC/Pt(II)‐b‐PEG shows higher solubility in aqueous solution and higher cytotoxicity towards human cervical cancer HeLa cells and human breast cancer MDA‐MB‐231 cells. In vitro release experiments revealed that the platinum drug‐loaded delivery system is relatively stable under physiological conditions (pH = 7.4 and 37 °C) but susceptible to acidic environments (pH = 5.6 and 37 °C) which would trigger the release of loaded drugs. Fluorescence microscopy studies revealed that this magnetic nanohybrid system possesses marked cell‐specific targeting in vitro in the presence of an external magnetic field. The results indicated that the prepared superparamagnetic MCNTs/FO@PC/Pt(II)‐b‐PEG nanohybrid system is a promising candidate for inhibiting the proliferation of cancer cells.     

Synthesis of new C2 symmetrical dibenzospirodiamide and dibenzospirodiamine as potential chiral auxiliaries and building blocks of ionophores

2,8‐Diazadibenzo[c,i]spiro[5,5]undecan‐1,7‐dione 3 are synthesized via reaction of malonic ester with 2‐nitrobenzyl bromide, followed by reduction‐cyclization in 86% overall yield. 2,8‐Diazadibenzo[c,i]‐spiro[5,5]undecane 4 was obtained by reduction of 3 with LiAIH₄ in 90% yield. N‐Alkylation of 3 with various alkylating reagents is studied.     

Synthesis of methyl 7-aryl(hetaryl, cyclohexenyl)-10-(1,3-benzodioxol-5-yl)-8-oxo-7,8,9,10,11,12-hexahydro-benzo[b][1,7]phenanthroline-9-carboxylates

Three-component condensation of quinolin-5-amine with methyl 2-(1,3-benzodioxol-5-yl)-4,6-dioxocyclohexane-1-carboxylates and aromatic aldehydes (or cyclohex-3-ene-1-carbaldehyde) afforded new hexahydrobenzo[b][1,7]phenanthroline derivatives. The condensation in butan-1-ol is strictly regioselective but not stereoselective, so that mixtures of cis- and trans-isomeric methyl 7-aryl(hetaryl, cyclohexenyl)-10-(1,3-benzodioxol-5-yl)-8-oxo-7,8,9,10,11,12-hexahydrobenzo[b][1,7]phenanthroline-9-carboxylates at a ratio of ～40: 60% are formed.     

Synthesis and antimicrobial activity of new functionalized derivatives of [1,2,4]triazolo[4,3‐a]pyrimidin‐5(1H)‐one

New functionalized 1,7‐diaryl‐6‐cyano‐1,2,4‐triazolo[4,3‐a]pyrimidin‐5(1H)‐one derivatives ( 5a–j ) were synthesized via reaction of 5‐cyano‐6‐phenyl‐2‐thiouracil 1 with the respective hydrazonoyl halides 2a–j and their biological activity was evaluated. The mechanism and the regioselectivity of the studied reactions are discussed. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:393–398, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20311     

Cascade Nitration/Cyclization of 1,7‐Enynes with tBuONO and H2O: One‐Pot Self‐Assembly of Pyrrolo[4,3,2‐de]quinolinones

Here we describe the one‐pot construction of the pyrrolo[4,3,2‐de]quinolinone scaffold by a cascade nitration/cyclization sequence of 1,7‐enynes with tBuONO and H₂O. The cascade proceeds through alkene nitration, 1,7‐enyne 6‐exo‐trig cyclization, C? H nitrations, and redox cyclization, and exhibits excellent functional group tolerance. The mechanism was investigated using in situ high‐resolution mass spectrometry (HR‐MS).     

Proton‐Induced Generation of Remote N‐Heterocyclic Carbene–Ru Complexes

The proton‐induced Ru?C bond variation, which was previously found to be relevant in the water oxidation, has been investigated by using cyclometalated ruthenium complexes with three phenanthroline (phen) isomers. The designed complexes, [Ru(bpy)₂(1,5‐phen)]⁺ ([ 2 ]⁺), [Ru(bpy)₂(1,6‐phen)]⁺ ([ 3 ]⁺), and [Ru(bpy)₂(1,7‐phen)]⁺ ([ 4 ]⁺) were newly synthesized and their structural and electronic properties were analyzed by various spectroscopy and theoretical protocols. Protonation of [ 4 ]⁺ triggered profound electronic structural change to form remote N‐heterocyclic carbene (rNHC), whereas protonation of [ 2 ]⁺ and [ 3 ]⁺ did not affect their structures. It was found that changes in the electronic structure of phen beyond classical resonance forms control the rNHC behavior. The present study provides new insights into the ligand design of related ruthenium catalysts.     

New Diarylheptanoids and Kavalactone from Alpinia katsumadai Hayata

Two new diarylheptanoids, katsumains A ( 1 ) and B ( 2 ), and one new kavalactone, katsumadain ( 3 ), together with the three known compounds (4E,6E)‐1,7‐diphenylhepta‐4,6‐dien‐3‐one ( 4 ), (5R,6E)‐1,7‐diphenyl‐5‐hydroxyhept‐6‐en‐3‐one ( 5 ), and cardamonin ( 6 ), were isolated from the seeds of Alpinia katsumadai Hayata . Their structures were elucidated mainly by spectroscopic methods (1D‐ and 2D‐NMR) and by mass spectrometry (HR‐ESI‐MS). Besides, the erroneous nomenclatures for (+)‐linderatin and (+)‐neolinderatin as given in [10] [11] were corrected to be 2′,4′,6′‐trihydroxy‐3′‐[(3R,4R)‐4‐isopropyl‐1‐methylcyclohex‐1‐en‐3‐yl]dihydrochalcone for (+)‐linderatin and 2′,4′,6′‐trihydroxy‐3′,5′‐bis[(3R,4R)‐4‐isopropyl‐1‐methylcyclohex‐1‐en‐3‐yl]dihydrochalcone for (+)‐neolinderatin, respectively.     

钌(II)配合物与酵母tRNA相互作用的等温滴定量热研究

The interaction of metal complex with RNA has been studied by isothermal titration calorimetry (ITC) for the first time. ITC experiments show that complex [Ru(phen)2MPIP]^2 {phen= 1,10-phenanthroline, MP[P-2-(4-methylphenyl)imidazo[4,5-f]-1, 10-phenanthroline} interacts with yeast tRNA in terms of a model for a singleset of identical sites through intercalation, which is consistent with our previous observation obtained from spectroscopic methods, and this binding process was driven by a moderately favorable enthalpy decrease in combination with a moderately favorable entropy increase, suggesting that ITC is an effective method for deep studying the interactions of metal complexes with RNA.     

Synthesis of two novel ring systems via photocyclization: Thieno[2′,3′:4,5]thieno[2,3-c][1,10]phenanthroline and thieno[3′,2′:4,5]thieno[2,3-c][1,10]phenanthroline

The synthesis of thieno[2′,3′:4,5]thieno[2,3-c][1,10]phenanthroline ( 5 ) and thieno[3′,2′:4,5]thieno-[2,3-c][1,10]phenanthroline ( 10 ) are described. Each compound was obtained in four steps from known starting materials. The basic skeleton of the molecule and of the phenanthroline ring were formed via photocyclization. The total assignment of ¹H-nmr spectra was accomplished with the aid of two-dimensional nmr methods.     

Dinuclear Complexes of Copper(I) with Crown Ether‐containing N‐Thiophosphorylated Bis‐thioureas and 2,2′‐Bipyridine or 1,10‐Phenanthroline: Synthesis,Characterization, and Picrate Extraction Properties

Reaction of O,O′‐diisopropylthiophosphoric acid isothiocyanate (iPrO)₂P(S)NCS with 1,10‐diaza‐18‐crown‐6, 1,7‐diaza‐18‐crown‐6, or 1,7‐diaza‐15‐crown‐5 leads to the N‐thiophosphorylated bis‐thioureas N,N′‐bis[C(S)NHP(S)(OiPr)₂]‐1,10‐diaza‐18‐crown‐6 ( H₂L^I ), N,N′‐bis[C(S)NHP(S)(OiPr)₂]‐1,7‐diaza‐18‐crown‐6 ( H₂L^II ) and N,N′‐bis[C(S)NHP(S)(OiPr)₂]‐1,7‐diaza‐15‐crown‐5 ( H₂L^III ). Reaction of the potassium salts of H₂L^I–III with a mixture of CuI and 2,2′‐bipyridine ( bpy ) or 1,10‐phenanthroline ( phen ) in aqueous EtOH/CH₂Cl₂ leads to the dinuclear complexes [Cu₂(bpy)₂L^I–III] and [Cu₂(phen)₂L^I–III] . The structures of these compounds were investigated by ¹H, ³¹P{¹H} NMR spectroscopy, and elemental analysis. The crystal structures of H₂L^I and [Cu₂(phen)₂L^I] were determined by single‐crystal X‐ray diffraction. Extraction capacities of the obtained compounds in comparison to the related compounds 1,10‐diaza‐18‐crown‐6, N,N′‐bis[C(=CMe₂)CH₂P(O)(OiPr)₂]‐1,10‐diaza‐18‐crown‐6, N,N′‐bis[C(S)NHP(O)(OiPr)₂]‐1,10‐diaza‐18‐crown‐6 towards the picrate salts LiPic, NaPic, KPic. and NH₄Pic were also studied.     

Synthesis,Characterization, and DNA‐Binding Properties of the Chiral Ruthenium(II) Complexes Δ‐ and Λ‐[Ru(bpy)2(dmppd)]2+ (dmppd = 10,12‐Dimethylpteridino[6,7‐f] [1,10]phenanthroline‐11,13(10H,12H)‐dione; bpy = 2,2′‐Bipyridine)

Two novel chiral ruthenium(II) complexes, Δ‐[Ru(bpy)₂(dmppd)]²⁺ and Λ‐[Ru(bpy)₂(dmppd)]²⁺ (dmppd = 10,12‐dimethylpteridino[6,7‐f] [1,10]phenanthroline‐11,13(10H,12H)‐dione, bpy = 2,2′‐bipyridine), were synthesized and characterized by elemental analysis, ¹H‐NMR and ES‐MS. The DNA‐binding behaviors of both complexes were studied by UV/VIS absorption titration, competitive binding experiments, viscosity measurements, thermal DNA denaturation, and circular‐dichroism spectra. The results indicate that both chiral complexes bind to calf‐thymus DNA in an intercalative mode, and the Δ enantiomer shows larger DNA affinity than the Λ enantiomer does. Theoretical‐calculation studies for the DNA‐binding behaviors of these complexes were carried out by the density‐functional‐theory method. The mechanism involved in the regulating and controlling of the DNA‐binding abilities of the complexes was further explored by the comparative studies of [Ru(bpy)₂(dmppd)]²⁺ and of its parent complex [Ru(bpy)₂(ppd)]²⁺ (ppd = pteridino[6,7‐f] [1,10]phenanthroline‐11,13 (10H,12H)‐dione).     

Rhodium(III)‐Catalyzed [3+2]/[5+2] Annulation of 4‐Aryl 1,2,3‐Triazoles with Internal Alkynes through Dual C(sp2)H Functionalization

A rhodium(III)‐catalyzed [3+2]/[5+2] annulation of 4‐aryl 1‐tosyl‐1,2,3‐triazoles with internal alkynes is presented. This transformation provides straightforward access to indeno[1,7‐cd]azepine architectures through a sequence involving the formation of a rhodium(III) azavinyl carbene, dual C(sp²)? H functionalization, and [3+2]/[5+2] annulation.     

Rhodium(III)‐Catalyzed [3+2]/[5+2] Annulation of 4‐Aryl 1,2,3‐Triazoles with Internal Alkynes through Dual C(sp2)?H Functionalization

A rhodium(III)‐catalyzed [3+2]/[5+2] annulation of 4‐aryl 1‐tosyl‐1,2,3‐triazoles with internal alkynes is presented. This transformation provides straightforward access to indeno[1,7‐cd]azepine architectures through a sequence involving the formation of a rhodium(III) azavinyl carbene, dual C(sp²) H functionalization, and [3+2]/[5+2] annulation.