Microwave-assisted synthesis of derivatives of khellinone under phase-transfer catalytic conditions

The microwave-assisted synthesis of four new 5-acetyl-4,7-dimethoxy-6-hydroxybenzofuran (khellinone) analogs is described. The structures of the obtained derivatives in the solid state are evaluated on the basis of ¹³C CP/MAS NMR spectra and theoretical calculations at DFT level. A single crystal X-ray diffraction structure is presented for 8-acetyl-7-hydroxy-4-methylcoumarin. 1,4-Bis(5-acetyl-4,7-dimethoxybenzofuran-6-yloxy)butane was evaluated for potential anticancer activity in an in vitro screening panel of 60 human tumor cell lines. Selected leukemia, non-small cell lung cancer, CNS, melanoma, ovarian, and breast cancer cell lines were sensitive to this compound. Correspondence: Elżbieta Hejchman, Department of Organic Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1, 02-097 Warsaw, Poland.     

Microwave-assisted Polycondensation of L-2-Hydroxy-3-phenylpropanoic Acid

The attempts to prepare novel biodegradable polymer carriers for drug controlled release systems have been tried in our group1,2. Poly (L-2-hydroxy-3-phenylpropanoic acid) (PLHPPA) can be considered as derivative of poly (lactic acid) (PLA) which has been applied as biomaterials in drug delivery systems, surgical repair and tissue engineering materials3 for its excellent biodegradability and biocompatibility. PLHPPA contains phenyl groups in its structure. It is designed as a hydrophobic…     

The basicity of unsaturated hydrocarbons as probed by hydrogen-bond-acceptor ability: bifurcated N-H+ ...pi hydrogen bonding

The competitive substitution of the anion (A(-)) in contact ion pairs of the type [Oct3NH+]B(C6F5)4 (-) by unsaturated hydrocarbons (L) in accordance with the equilibrium Oct3NH+...A(-) + nL right arrow over left arrow [Oct3NH+...Ln]A(-) has been studied in CCl4. On the basis of equilibrium constants, K, and shifts of nuNH to low frequency, it has been established that complexed Oct3NH...+Ln cations with n=1 and 2 are formed and have unidentate and bifurcated N--H+...pi hydrogen bonds, respectively. Bifurcated hydrogen bonds to unsaturated hydrocarbons have not been observed previously. The unsaturated hydrocarbons studied include benzene and methylbenzenes, fused-ring aromatics, alkenes, conjugated dienes, and alkynes. From the magnitude of the redshifts in the N--H stretching frequencies, Delta nuNH, a new scale for ranking the pi basicity of unsaturated hydrocarbons is proposed: fused-ring aromatics相似文献   

Ferrocene Compounds. XXXI. Structure of 3-Ferrocenylpropanoic Acid

The title compound was prepared by modified procedure and characterized by means of IR, [¹H] and [¹³C] NMR spectroscopy. The structure was also determined by a single-crystal X-ray diffraction (XRD). 3-Ferrocenylpropanoic acid crystallizes as orange prisms in the triclinic space group P with a = 7.645(1) Å, b = 7.953(1) Å, c = 9.961(1) Å, = 81.67(1), = 68.43(1), = 83.76(1), V = 556.3(1) ų, Z = 2, R = 0.0435. In the ferrocene skeleton, Fe-C distances are in the range 2.033(2)–2.052(2) Å and C C distances in the range 1.412(5)–1.431(3) Å. The angle defined by ring centers and Fe atom is 177.7(1). The cyclopentadienyl rings are twisted from the eclipsed conformation by 8.3(2) (average value). In the structure was observed strong intermolecular hydrogen bond of 2.670(3) Å forming cyclic dimers of the R₂ ² (8) type.     

Crystal Structure of Ethanolamine 5-Nitrosalicylic Acid Organic Adduct

1 INTRODUCTION The organic non-linear optical material[1] playsan important role in the research area of non-linearoptical materials. In recent years, many new non-linear optical second harmonic generation (SHG) ma-terials of organic adduct have come…     

Contribution of Neutron Diffraction to the Crystal Structure Determination of 1-Hydroxy-1-Phosphono-Pentyl-Phosphonic Acid Dimethyl Ammonium Salt

The crystal structure of 1-hydroxy-1-phosphono-pentyl-phosphonic acid dimethylammonium salt has been determined by neutron diffraction measurements on single crystals at room temperature (triclinic, space group P-1, a=11.419(23) Å, b=10.447(18) Å, c=6.211(9) Å, α=92.041(2)°, β=95.870 (3)°, γ=110.408(2)°, V=689(2) ų). Refinements of the structure using 1195 observed structure factors converged to the final R=0.068. Results have put in evidence that acids of the hydroxybisphosphonic family can protonate volatile alkaline species like dimethylamine to give particularly stable crystals. The hydrogen bonds formed by the dimethylammonium cation link columns of hydroxybisphosphonate groups parallel to the [010] direction. The structure is built up by alternated hydrophobic/polar layers parallel to the (100) plane.     

Microwave-assisted synthesis of 1,5-dioxo-3-substituted [5]ferrocenophanes

The Claisen-Schmidt reaction between 1,1′-diacetylferrocene and ferrocenecarboxaldehyde under microwave irradiation has been investigated in different conditions. The selective synthesis of 1,5-dioxo-3-ferrocenyl[5]ferrocenophane has been achieved and a simple protocol for its purification was established. The reaction was generally applicable to other non-enolizable aldehydes and the corresponding 1,5-dioxo-3-substituted [5]ferrocenophanes were obtained in high yield within 30 min.     

Synthesis and Crystal Structure of a Three-dimensional Manganese(Ⅱ)Complex Constructed via Covalent and Hydrogen Bonds

1INTRODUCTIONCrystalengineeringofone-,two-andthree-dimensionalsupramolecularcomplexesiscurrentlyofgreatinterestowingtothefascinatingstructuraldiversityandpotentialapplicationsinmaterials,suchaselectricconductivity,magnetism,host-guestapplication,molecularrecognitionandcatalysis[1,2].Severaltypesofinteractions,suchascoordinationcovalentbond,hydrogenbond,p-pstackingandelectrostaticinteractionscanbeusedtoconstructextendedsupramolecularframeworks[3~6],butcoordinationbondingandhydrogenbondingin…     

3-羟基-1-金刚烷甲酸钴邻菲略啉配合物的合成和晶体结构

以硫酸钻、邻菲咯啉（phen）和3-羟基-1-金刚烷甲酸（HOC10H14COOH）为原料,合成了配合物[Co（HOG10H14COO）2（H2O）（phen）]·H2O;利用元素分析、红外光谱、热重分析对产物进行了表征,采用单晶X射线衍射方法测定了其晶体结构．结果表明,所合成的配合物C34H42N2O8Co属于单斜晶系,空间群C2／c,a=2．69798（7）nm,b=1．14319（3）nm,c=2．29092（6）nm,β=120．498（1）°,V665．63,F（000）=2808,Dc=1．452g·cm^-3,μ（Mo-Kα）=0．765mm^-1;R1=0.0805,wR2=0.2209,其通过氢键和π-π堆积作用相结合,形成稳定的二维超分子结构．     

吡嗪-2,3,5,6-四甲酸镍配合物[Ni(ptcH2)(bpy)(H2O)]的水热合成、结构及性质

A complex of nickel(Ⅱ) with pyrazine-2,3,5,6-tetracarboxylic acid and 2,2′-bipyridine, [Ni(ptcH₂)(bpy)(H₂O)], was synthesized by hydrothermal reaction of Ni(NO₃)₂·6H₂O with pyrazine-2,3,5,6-tetracarboxylic acid and 2,2′-bipyridine at 160 ℃ and characterized by elemental analysis, IR and X-ray diffraction single crystal structure determined. The crystal belongs to Monoclinic system, with space group P2₁/c, a=1.327 9(7) nm, b=1.279 7(7) nm, c=1.161 4(7) nm; β=113.435(8)°, V=1.810 6(17) nm³, Z=4. The coordination environment of nickel(Ⅱ) ion is a distorted octahedral geometry. The title complex is a mononuclear structure which is assembled into 3D supramolecular architecture by strong hydrogen bonds. CCDC: 661507.     

Synthesis, Crystal Structure and Properties of a Europium Complex with 3-Iodobenzoic Acid and 2,2'-Bipyridine

The complex [Eu(3-IBA)3·2,2'-bipy]2 was synthesized from 3-iodobenzoic acid (3-HIBA), 2,2'-bipyridine (2,2'-bipy) and EuCl3·6H2O by hydrothermal synthesis, and its crystal structure was determined by X-ray single-crystal diffraction. It is of triclinic, space group P1, with a = 10.958(2), b = 12.311(3), c = 12.556(3) A, α = 81.549(3), β = 82.404(4), γ = 78.348(3)°, Mr = 1049.15, V = 1631.7(6) 3, Z = 1, Dc = 2.135 g/cm3, F(000) = 980, λ(MoKα) = 0.71073 , μ(MoKα) = 4.804 mm-1, the final R = 0.0329 and wR = 0.0723 for 4640 observed reflections with I > 2σ(I). The Eu(Ⅲ) ion is eight-coordinated and two Eu(Ⅲ) ions are held together by four 3-iodobenzoate groups in the bidentate bridging mode. The complex was characterized by DTA-TG, IR, UV and fluorescence spectra.     

Crystal Structure of Nicotinic Acid·3,5-dinitrobenzoic Acid Organic Adduct

1INTRODUCTIONThedevelopmentofhighlyefficientnonlinearoptical(NLO)crystalsforvisibleandultraviolet(UV)regionsisextremelyimportantforbothlaserspectroscopyandlaserprocessing.Themainmeritsoforganicmaterialscomparedwithinorganiconesforsuchsecond-harmonicgenera…     

Microwave-assisted nickel(II) acetylacetonate-catalyzed arylation of aldehydes with arylboronic acids

Applying sealed vessel microwave heating at 180 °C in toluene the arylation of aromatic and aliphatic aldehydes with arylboronic acids using 1-2 mol % of Ni(acac)₂ as a catalyst can be performed efficiently within 10-30 min providing the desired diarylmethanols or benzyl alcohols in good yields.     

Preparation and Crystal Structure of an Acidic Long-chain Polyphosphate: CaH2(PO3)4

Preparation and crystal structure of an acidic polyphosphate of calcium is described. CaH₂(PO₃)₄: monoclinic, P2₁/c, with Z = 2, and a = 5.686(1), b = 9.676(4), c = 8,844(3) Å, β = 92.35(2)°. The crystal structure was solved using 2 321 unique reflections with a final R value of 0.017. The compound is characterized by infinite (PO₃)_n chains running along c and linked together in a three-dimensional way by Ca? O and hydrogen bonds. The two-dimensional linkage of the phosphoric chains by hydrogen bonds is compared to those already observed in ErH(PO₃)₄ and BiH(PO₃)₄.     

Synthesis,X-Ray Crystal Structure,and Computational Study of Novel Pyrazolo[3,4-B]pyridin-3-Ol Derivatives

Abstract

6-(Pyrazol-1-yl)pyrazolo[3,4-b]pyridin-3-ol (3a) was synthesized by cyclization reaction from 2,6-dichloro-4-methylnicotinonitrile. The related sulfonyl and acylated product (4–7) were obtained from the compound 3a and different sulfonyl and acyl chloride compounds. The sulfonylation of the compound 3a afforded the O1-sulfonylation, only, to give 3-substituted products 4–6. The acylation of the compound 3a gives 1,3-diacylated products 7 via N2, O1-diacylation. All compounds were characterized by spectroscopic methods and the molecular structures of 3a and 4–7 were determined by X-ray diffraction analysis. The molecular structure of 5 and 7 were studied by density functional theory (DFT) calculations, reproduced the experimental geometry. The energies of the three molecules of the tautomeric forms of the compound 3a were calculated by DFT calculations. It was shown that the 3a predominated in the gas phase. Besides, molecular electrostatic potential (MESP) and frontier molecular orbital (FMO) analysis of the compound 3a were investigated by theoretical calculations.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text, tables, and figures.]     

Microwave-assisted synthesis of 1-aryl-3-acetyl-1,4,5,6-tetrahydrobenzimidazo[1,2-d][1,2,4]triazine: first example of a novel ring system

Novel highly functionalized benzimidazoles were synthesized in two steps by microwave irradiation: construction of the benzimidazole ring followed by ring closure to the new tricyclic system.     

微波辅助离子液体法在液相合成中的应用

作为一种新型的绿色化学合成方法,微波辅助离子液体法融合了离子液体与微波加热法的优点,具有合成快速、操作简便、产率高,绿色环保等特点,在液相合成方面体现出明显的优势。本文综述了离子液体作为微波吸收剂在液相有机合成、无机纳米材料合成方面的研究进展,对比分析了微波辅助离子液体法同多种传统方法的应用效果,阐明了该方法的优势,并展望该领域今后的发展方向。     

The Unexpected Base-Pairing Behavior of Cyanuric Acid in RNA and Ribose versus Cyanuric Acid Induced Helicene Assembly of Nucleic Acids: Implications for the Pre-RNA Paradigm

The cyanuric acid (CA) heterocycle forms supramolecular structures with adenine nucleobases/nucleosides and oligonucleotides, leading to speculation that they can act as forerunners to RNA. Herein, the assembly behavior of RNA containing CA and CA–ribose nucleoside was studied. Contrary to previous reports, CA in RNA and the CA-ribonucleoside resulted in destabilization of supramolecular assemblies, which led to a reevaluation of the CA–adenine hexameric rosette structure. An unprecedented noncovalent supramolecular helicene structure is proposed to account for the striking difference in behavior, which has implications for novel paradigms for reorganizing the structures of nucleic acids, the synthesis of long helicenes, and pre-RNA world paradigms. The results caution against extrapolating the self-assembly behavior of individual heterocycles from the level of monomers to oligomers because the base-paring properties of (non-)canonical nucleobases are impacted by the type of oligomeric backbone to which they are attached.     

Microwave-assisted synthesis of 2-aminothiophene-3-carboxylic acid derivatives, 3H-thieno[2,3-d]pyrimidin-4-one and 4-chlorothieno[2,3-d]pyrimidine

A two-minute microwave irradiation allowed the synthesis of several 2-aminothiophene-3-carboxylic acid derivatives. Their efficient transformation to thieno[2,3-d]pyrimidin-4-one and the corresponding 4-chloro derivative is also reported under microwave irradiation.     

Synthesis and Structure Analysis of N-（Dehydroabietyl）maleamic Acid

N-(Dehydroabietyl)maleamic acid was synthesized from dehydroabietylamine and maleic anhydride.Its structure was characterized by IR,1 H-and 13 C-NMR spectra.The stereo structure of the title compound was also unambiguously confirmed by X-ray crystal structure analysis.The white crystal crystallizes in the monoclinic system,space group P2 1 with a=12.075(2),b=10.377(2),c=17.840(4),β=100.31(3) °,V=2199.3(8) 3,R=0.0618 and wR=0.1437.Two crystallographically independent molecules with different conformations co-exist in the unit.In each molecule,the two cyclohexane rings form a trans ring junction with chair and half-chair conformations,respectively.The C=C double bond between two carbonyl groups is in a Z configuration.Intermolecular and intramolecular hydrogen bonds coexist to stabilize the structure.