Uncommon secondary metabolites from Etlingera pavieana rhizomes

From the rhizomes of Etlingera pavieana (Pierre ex Gagnep.) R.M. Sm., four phenylpropens, (E)-3-(4-methoxyphenyl)prop-2-en-1-amine (1), (E)-4-methoxycinamaldehyde (2), (E)-4-methoxycinamic acid (3) and (E)-1-methoxy-4-(3-methoxyprop-1-enyl)benzene (4), together with two other compounds, (E)-((E)-3-(4-methoxyphenyl)allyl)3-(4-hydroxyphenyl)acrylate (5) and 4-methoxybenzoic acid (6) were isolated. This is the first report on the presence of all compounds in Etlingera. Compounds 1 and 5 have been previously synthesised, but this is the first report of their isolation from a natural source. Compound 5 exhibited weak activity against Mycobacterium tuberculosis with MIC 50.00 μg/mL and cytotoxic activity against the KB, MCF7 and NCI-H187 cells with IC₅₀ values of 25.11, 20.16 and 34.83 μg/mL, respectively.     

含均三唑环的新型联苯四唑衍生物的合成及抗菌活性

通过4-芳基-5-(4-吡啶基)-1,2,4-三唑-3-硫醇(1)和2-三苯基甲基-5-(4′-溴甲基联苯-2-基)-四唑(5)反应, 制得一系列新的S-烷基化产物(6), S-烷基化产物在酸性条件下脱保护, 得到了14个未见文献报道的含1,2,4-三唑类联苯四唑(7a～7n)衍生物. 结构经元素分析, IR, NMR及FAB-MS确认. 对大肠杆菌、链球菌、枯草杆菌、金黄色葡萄球菌初步抑菌试验证明, 多数化合物表现了较好的抑菌活性.     

Claisen aromatic amino rearrangement in the series of fluorinated anilines

The effect ofmeta-substituents in the aromatic ring on the route of Claisen rearrangement ofN-(pent-3-en-2-yl)-3-fluoro(or 3-trifluoromethyl, 3,4-difluoro)anilines induced by ZnCl₂ was investigated. The formation of two possibleortho-alkenylated reaction products was observed. The ratio of these isomers depends on the nature of the acid catalyst. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 188–190, January, 1998.     

Synthesis,Characterization, Antimicrobial Activities,and Structural Studies of Lanthanide (III) Complexes with 1-(4-Chlorophenyl)-3-(4-fluoro/hydroxyphenyl)prop-2-en-1-thiosemicarbazone

Twelve coordinate lanthanide (III) complexes with the general composition [Ln L₃X_n(H₂O)_n] where Ln = Pr(III), Sm(III), Eu (III), Gd (III), Tb (III), Dy (III), X = Cl^?1, NO₃ ^?2, n = 2–7, and L is 1-(4-chlorophenyl)-3-(4-fluoro/hydroxyphenyl)prop-2-en-1- thiosemicarbazone have been prepared. The lanthanide complexes (5) were derived from the reaction between 1-(4-chlorophenyl)-3-(4-fluoro/hydroxyphenyl)prop-2-en-1-thiosemicarbazone (4) with an aqueous solution of lanthanide salt. Chalcone thiosemicarbazone ligand (4) was prepared by the reaction of [1-(4-chlorophenyl)-3-(4-fluoro/hydroxyphenyl)]prop-2-enone (chalcone) (3) with thiosemicarbazide in the presence of hot ethanol. All the lanthanide-ligand 1:3 complexes have been isolated in the solid state, are stable in air, and characterized on the basis of their elemental and spectral data.

Thiosemicarbazone ligands behave as bidentate ligands by coordinating through the sulfur of the isocyanide group and nitrogen of the cyanide residue. The probable structure for all the lanthanide complexes is also proposed. The chalcone thiosemicarbazone ligands and their lanthanide complexes have been screened for their antifungal and antibacterial studies. Some of the synthesized lanthanide complexes have shown enhanced activity compared with that of the free ligand.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Synthesis of novel N-aryl-N-(1H-tetrazol-5-yl)benzenesulfonamides in water

N-Aryl-N-(1H-tetrazol-5-yl)benzenesulfonamides were synthesized via an eco-friendly protocol using ZnBr₂-catalyzed [2 + 3] cycloaddition reaction of N-cyano-N-arylbenzenesulfonamides and sodium azide under reflux conditions in water. The products were obtained in excellent yields via an easy work-up procedure.     

Synthesis ofpara-cyclopentylanilines fromortho-(cyclopent-1′-enyl)anilines

ortho—para-Migration of the cyclopentenyl fragment in 2-(cyclopent-1′-enyl)aniline or 2-(cyclopent-1′-enyl)-6-methylaniline hydrochloride at 200 °C gives 4-cyclopentylaniline or 4-cyclopentyl-2-methylaniline. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 171–173, January, 2000.     

Reduction of (<Emphasis Type="Italic">E</Emphasis>)-3-aryl-2-(thiazol-2-yl)acrylonitriles with lithium aluminum hydride

Reduction of (E)-3-aryl-2-(4-arylthiazol-2-yl)acrylonitriles with lithium aluminum hydride in dry ether afforded (Z)-1-amino-3-aryl-2-(thiazol-2-yl)prop-1-ene derivatives in 15 to 40% yields. The structure of (Z)-1-amino-3-(2-chlorophenyl)-2-[4-(4-methylphenyl)thiazol-2-yl]prop-1-ene was confirmed by X-ray diffraction analysis. Dedicated to Academician N. K. Kochetkov on the occasion of his 90th birthday. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1301–1303, May, 2005.     

Facile one pot multicomponent synthesis of novel 4-(benzofuran-2-yl)-2-(3-(aryl/heteryl)-5-(aryl/heteryl)-4,5-dihydro-1H-pyrazol-1yl)thiazole derivatives

An efficient base catalyzed one pot multicomponent reaction of aryl/hetryl chalcones, thiosemicarbazide and 1-(benzofuran-2-yl)-2-bromoethan-1-one was developed to synthesize the novel 4-(benzofuran-2-yl)-2-(3-(aryl/heteryl)-5-(aryl/heteryl)-4,5-dihydro-1H-pyrazol-1yl)thiazole derivatives.     

Synthesis of 4-amino-substituted but-2-en-4-olides

Previously unknown 4-amino derivatives of spiro-annelated Δ²-butenolide were synthesized by the addition of various amines at the activated triple bond of 4-hydroxy-2-alkynoic esters. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2761–2770, December, 2005.     

The kinetics of oxidation of 1-chloro-2-(4-isopropylphenyl)-2-methylpropane by molecular oxygen

The kinetics of formation of 2-[4-(1-chloro-2-methylpropan-2-yl)phenyl]propan-2-yl hydroperoxide during the azobisisobutyronitrile-initiated oxidation of 1-chloro-2-(4-isopropylphenyl)-2-methylpropane by molecular oxygen at 70–100 °C was studied. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1135–1137, June, 2000.     

Spectral,luminescent, and photophysical properties of dipyrrolylbenzenes

Dipyrroles with a phenylene bridge, 1,4-bis(pyrrol-2-yl)benzene, 4-(1-vinylpyrrol-2-yl)-1-(pyrrol-2-yl)benzene, and 1,4-bis(1-vinylpyrrol-2-yl)benzene, show intense room-temperature fluorescence in solutions. Analysis of electronic absorption spectra, fluorescence spectra, and results of B3LYP, TD B3LYP, and CIS quantum chemical calculations showed that the introduction of a bulky substituent in position 1 of the pyrrole ring makes the ground-state structures of dipyrrolylbenzenes less planar. Excited-state geometries of all molecules relax to more planar conformations. An increase in the probability of nonradiative transitions has little effect on the quantum yields of fluorescence (Φ_f) of dipyrrolylbenzenes. Even for 1,4-bis(1-vinylpyrrol-2-yl)benzene, where the pyrrole rings deviate from the benzene ring plane by 44°, the fluorescence efficiency remains high enough (Φ_f = 0.7). Substitution at nitrogen atoms has little effect on positions of fluorescence band maxima. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1433–1438, July, 2008.     

Facile Synthesis of 2-(4-Hydroxybiphenyl-3-yl)-1H-indoles from Anilines and 5′-Bromo-2′-hydroxyacetophenone

2-Arylindoles are attractive scaffolds because they are found in many pharmacologically active molecules. In this study, we describe the facile synthesis of diverse 2-(2-hydroxyphenyl)-1H-indoles from anilines and 5′-bromo-2′-hydroxyacetophenone in two steps using palladium-catalyzed indole cyclization as a key reaction. The indole cyclization was primarily controlled by the substituent properties of anilines. Suzuki-coupling reactions of 2-(5′-bromo-2′-hydroxyphenyl)-1H-indoles with arylboronic acids provided the corresponding 2-(4-hydroxybiphenyl-3-yl)-1H-indoles in moderate yield.     

Synthesis, Crystal Structure and Antitumor Activity of 4-tert-Butyl-N-（2-fluorophenyl）-5- （1H-1,2,4-triazol-1-yl）-thiazol-2-amine

The title compound has been synthesized by the reaction of 1-bromo-3,3-dime- thyl-1- (1H-1,2,4-triazol-1-yl)butan-2-one with 1-(2-fluorophenyl)thiourea, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the orthorhombic system, space group Pbca with a=15.2568(6), b=12.1533(5), c=16.7307(7) , Z=8, V=3102.2(2)3, Mr=317.39, Dc=1.359 g/cm3, S=1.05, μ=0.223 mm-1, F(000)=1328, the final R=0.034 and wR=0.097 for 2590 observed reflections (I>2σ(I)). X-ray crystal structure presents the intramolecular N-H…N hydrogen bond, which plays an important role in stabilizing the crystal structure. In addition, the preliminary biological test on the title compound shows good antitumor activity, with IC50 of 0.122 μmol/mL against the Hela cell line.     

Unique CuI-pyridine based ligands catalytic systems for N-arylation of indoles and other heterocycles

Two pyridine-based ligands (N-((pyridin-2-yl) methyl) pyridin-2-amine) L1 and (N-((pyridin-2-yl) methylene) pyridin-2-amine) L2 are explored in present work which are inexpensive, effective and environmentally benign in their properties. These have been utilized for C-N cross coupling reaction resulting in N-arylation. The N-arylation of indole, imidazole and triazole have been successfully carried out with different aryl and heteroaryl halides using these ligands.     

Construction of four d10 coordination polymers containing binuclear rings as building blocks from 4′-(2H-tetrazol-5-yl)biphenyl-4-carboxylic acid

Four coordination polymers based on 4′-(2H-tetrazol-5-yl)biphenyl-4-carboxylic acid (H₂TBPC), [Zn(μ₃-TBPC)(H₂O)]_n (1), [Zn(μ₃-TBPC)(Me₂NH)]_n (2), [Cd(μ₃-TBPC)(bpy)]_n (bpy = 4,4′-bipyridine, 3), and [Cd(μ₄-TBPC)(H₂O)]_n (4), were constructed under hydrothermal conditions. The compounds are composed of M₂(TBPC)₂ binuclear ring as a building block. In 1–3, the binuclear rings are interconnected to three different 2-D networks with the same (4·8²) topology. In 4, the binuclear rings are arranged into a 3-D framework with PtS-type topology. The results revealed that the structural diversity is mainly attributed to the coordination geometries of metal ion, the coordination modes of TBPC^2?, and the auxiliary ligand. The thermal stabilities and luminescent properties of 1–4 have also been studied.     

Microwave Irradiation: Alternative Heating Process for the Synthesis of Biologically Applicable Chromones,Quinolones, and Their Precursors

Microwave irradiation has become a popular heating technique in organic synthesis, mainly due to its short reaction times, solventless reactions, and, sometimes, higher yields. Additionally, microwave irradiation lowers energy consumption and, consequently, is ideal for optimization processes. Moreover, there is evidence that microwave irradiation can improve the regioselectivity and stereoselectivity aspects of vital importance in synthesizing bioactive compounds. These crucial features of microwave irradiation contribute to its inclusion in green chemistry procedures. Since 2003, the use of microwave-assisted organic synthesis has become common in our laboratory, making our group one of the first Portuguese research groups to implement this heating source in organic synthesis. Our achievements in the transformation of heterocyclic compounds, such as (E/Z)-3-styryl-4H-chromen-4-ones, (E)-3-(2-hydroxyphenyl)-4-styryl-1H-pyrazole, (E)-2-(4-arylbut-1-en-3-yn-1-yl)-4H-chromen-4-ones, or (E)-2-[2-(5-aryl-2-methyl-2H-1,2,3-triazol-4-yl)vinyl]-4H-chromen-4-ones, will be discussed in this review, highlighting the benefits of microwave irradiation use in organic synthesis.     

Synthesis and characterization of polymeric triphenyltin and cyclotetrameric tricyclohexyltin 2-(1H-imidazol-1-yl)acetates

The reaction of 2-(1H-imidazol-1-yl)acetic acid with (Ph₃Sn)₂O or Cy₃SnOH (Cy?=?cyclohexyl) yields triphenyltin 2-(1H-imidazol-1-yl)acetate (1) and tricyclohexyltin 2-(1H-imidazol-1-yl)acetate (2), respectively. 2-(1H-imidazol-1-yl)acetates in these two complexes show remarkably different coordination modes. Complex 1 forms a polymeric chain structure through intermolecular Sn–N interactions, while 2 displays a 28-membered macrocyclic tetranuclear structure by the assembly of Sn–N coordination bonds.     

(Alk-1-ynyl)organylthiocarbenes: generation and reactions with olefins

1-Substituted 1-chloro-3-organylthiopropa-1,2-dienes 1a–f belonging to previously unknown type of allenic compounds were synthesized by chlorination of 1-organylthioalk-1-ynes 3a–f with N-chlorosuccinimide. The reactions of compounds 1a–f with Bu^tOK in hexane at –20 °C are accompanied by -elimination of HCl to give new alk-1-ynyl(organylthio)carbenes 2a–f, which add to olefins to form the corresponding 1-(alk-1-ynyl)-1-organylthiocyclopropanes 5 in yields of up to 60%. The electrophilic properties of carbenes 2 were confirmed experimentally.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2440–2447, November, 2004.     

Syntheses,crystal structures,and luminescent properties of three metal coordination polymers based on adipic acid and 2-(pyridine-3-yl)-(1H)-benzimidazole

Three new metal coordination polymers constructed from adipic acid and 2-(pyridin-3-yl)-(1H)-benzimidazole ligands, [M(ADP)(3PBI)₂(H₂O)₂]·2H₂O (M = Ni and Co for 1 and 2, respectively) and [Cd(ADP)(3PBI)(H₂O)] (3) [ADP = adipic acid dianion; 3PBI = 2-(pyridin-3-yl)-(1H)-benzimidazole], have been synthesized by hydrothermal reactions and were characterized by X-ray single-crystal diffraction, elemental analyses, IR, powder X-ray diffraction, and thermogravimetry. Complexes 1 and 2 are isostructural. Both form a 1-D linear chain structure, which is further assembled into a 3-D supramolecular framework by π?π stacking and hydrogen bonding interactions. Complex 3 possesses a binuclear unit and displays a 2-D layer which is further extended to a 3-D supramolecular architecture via hydrogen bonding and other weak packing interactions. The luminescent properties of 3 were investigated in the solid state at room temperature.