The new ether derivative of phenylpropanoid and bioactivity was investigated from the leaves of Piper betle L.

Abstract

A new ether derivative of phenylpropanoid compound, γ-(γ′-isohydroxychavicol)-chavicol octanyl ether (K1) along with one known phenylpropanoid named allyl-pyrocatechol or hydroxychavicol (2) were isolated from Piper betle var. kali collected from Tumluk district, West Bengal India. We first report the presence of compound K1 in the genus Piper. Their structures were established on the basis of various spectroscopic analyses. Compounds K1 and 2 showed excellent antioxidant DPPH free radical scavenging activity with IC₅₀ values of 4.61 and 4.12?µg/mL compared to ascorbic acid as a standard antioxidant drug with IC₅₀ value of 3.42?µg/mL, respectively. Evaluation of in vitro cytotoxic activities of compounds K1 and 2 showed significant effects against human oral cancer cell lines (AW13516 and AW8507), human hepatoma cell lines (HEPG2 and PLC-PRF-5) and a human pancreatic cell line (MIA-PA-CA-2), compared to Doxorubicin^® as a standard cytotoxic drug with GI₅₀ values of <10 and 18.18?µg/mL.     

New pyranosyl cembranoid diterpenes from Sarcophyton trocheliophorum

During our continual searching programme for novel bioactive metabolites from Sarcophyton trocheliophorum, collected from Red Sea, we describe herein the isolation and structural elucidation of further two new pyrane-based cembranoid diterpenes: 9-hydroxy-7,8-dehydro-sarcotrocheliol (1) and 8,9-expoy-sarcotrocheliol acetate (2), along with the well-known sarcotrocheliol acetate (3), (+)-sarcophine (4), (+)-sarcophytoxide (5) and (-)-sarcophytoxide (6). The chemical structures of compounds 1 and 2 were determined on the basis of 1D and 2D NMR (¹H, ¹³C, ¹H–¹H COSY, HMQC, HMBC and NOE), mass spectra (ESI and HR-ESIMS) and by comparison with related structures. The antimicrobial activities of the reported compounds 1–6 were investigated. According to the molecular docking study of compounds 1–6 using 3D structure of α,β tubulin in complex with taxol (PDB code 1JFF) and epothilone A (PDB code 1TVK), sarcophine (4) displayed the highest affinity towards both crystal structures, followed by 5 and 6, meanwhile pyrane-based cembranoid diterpenes (1–3) showed less affinity.     

Two 3D supramolecular polymers constructed from an amino acid and a high-nuclear Ln6Cu24 cluster node

The first successful attempt to construct 3D supramolecular frameworks with high-nuclear 3d-4f heterometallic clusters as a node is reported. The self-assembly of Ln3+, Cu2+ and amino acid in solution leads to the formation of two polymers, 35-nuclear complex [Sm6Cu29] 1 with a primitive cubic net-like structure and 36-nuclear complex [Nd6Cu30] 2 with a face-centred cubic network type structure. Glycine and L-proline, respectively, were used as ligands. It should be noted that 2 has a chiral framework. X-ray structure analyses show that 1 crystallizes in the triclinic P1 space group (a=19.6451(8), b=20.4682(8), c=20.7046(8) A, alpha=89.453(1), beta=66.290(1), gamma=68.572(1) degrees, V=7003.0(5) A3 and Z=1) and 2 belongs to the cubic P2(1)3 space group (a=b=c=32.4341(3) A, V=34 119.7(5) A3 and Z=4). Both complexes utilize Ln6Cu24 octahedral clusters as nodes and trans-Cu(amino acid)2 groups as bridges. Electrical conductivity measurements reveal that both polymers behave as semiconductors.     

Iodinated 1,4-naphthoquinones

Iodination of 5-amino- and 6-amino-1,4-naphthoquinones with I₂ and HIO₃ in aqueous dioxane occurs only at the benzoid ring. Depending on the reaction conditions, either aminoiodo- or aminodiiodonaphthoquinones are produced. Diazotization of these compounds followed by reduction or replacement of the diazo group with iodine affords mono- or polyiodo derivatives of 1,4-naphthoquinone. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1465–1469, June, 2005.     

Qualitative estimation of the dependence of the number of energetic compounds on their oxygen coefficient

The ratio between the numbers of structural formulas of C,H,N,O-containing energetic compounds belonging to the classes of fuels (low values of the oxygen coefficientA), explosives (mediumA), and oxidants (highA values) was studied by a computer generation procedure. The number of the theoretically possible structural formulas was found to decrease rapidly on going from fuels to explosives and then to oxidants; this observation agrees with the data on the numbers of various energetic compounds currently used and proposed. The strategy of the search for new compounds with the specified properties is described in brief, and its applicability to the search for explosives and oxidants with a small (up to 12) number of atoms in a molecule is evaluated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1304–1310, July, 1998.     

γ-Zirconium and γ-Titanium Phosphates Platinum Intercalation Compound Preparation, characterization and thermal behaviour

Inorganic ion-exchangers with a layered structure such as γ-zirconium and γ-titanium phosphates, intercalated with organic diamines, are able to exchange Pt²⁺ ions to give new intercalation compounds that can be utilized in heterogeneous catalysis. The experiments performed at different temperatures (25 and 45°C), show different ion uptakes, greater at 45°C and for the materials derived from γ-zirconium phosphate. After platinum exchange, all the materials show an amorphization in the XRD if compared with their precursors. The thermal behaviour of the platinum materials is specific, depending on the exchanger used and the ligand inside the exchanger. Pt²⁺ ion has a catalytic effect on ligand elimination in the γ-zirconium phosphate platinum compounds, but not in those derived from γ-titanium. All the obtained yellow materials show a small step in the TG curves and simultaneously we have the Pt²⁺→Pt⁰ reduction: this is confirmed by XRD registered at the temperatures of the thermal effect, showing peaks at d_hkl=2.27 and 1.95 Å. This revised version was published online in July 2006 with corrections to the Cover Date.     

Principal component analysis of carbon-13 substituent-induced chemical shifts of some unsaturated compounds

Principal component analysis (PCA) is applied to 32 disubstituted unsaturated compounds (Y–CH₂–X): cyanides, oximes and propenes; bearing 12 -substituents: F, Cl, Br, I, OMe, OEt, SMe, SEt, NMe₂, NEt₂, Me, and Et. The experimental ¹³C chemical shifts for the -carbon and functional carbon atoms are correlated with theoretically derived molecular properties, i.e. partial charges, electronegativity, hardness, dipole moments and the nuclear repulsion energies. In the first PCA, the clustering of these three classes of organic compounds occurred mostly because of the chemical shifts and partial charges, and also of the dipole moments, hardness and electronegativity parameters as confirmed by loading graph. A strong grouping is observed in the second PCA, showing the chemical shift dependence on the type of heteroatom substituents. Therefore, sulfur, nitrogen, oxygen and neutral groups exhibit four types of C-13 SCS influences, indicating that the heteroatom (Y) properties play a significant role on the effects on chemical shifts. The -halogenated compounds represent a very heterogeneous group due to possible orbital interactions between the functional group and the substituent. The third PCA shows the grouping of F, Cl, Br and I derivatives, confirming the second PCA results that same halogen presents the same or very similar effects on the chemical shifts.     

Stable silica gel-bound crown ethers. Selective separation of metal ions and a potential for separations of amine enantiomers

Silica gel-bound crown ethers and aza macrocycles have been synthesized with the attaching arm connected to the carbon framework of the macrocycles. The interactions of these bound macrocycles with cations are almost identical to those involving the analogous free macrocycles. This has allowed for predictable cation separation, concentration, and removal processes to be performed on a small scale. Quantum mechanical calculations and NMR measurements indicate that similarly bound chiral macrocycles will be capable of use in separating chiral organic amines.Dedicated to the memory of Professor James J. Christensen who died on 5 September 1987.     

Oxidation of allylic alcohols, amines, and sulfides mediated by assembled triphase catalyst of phosphotungstate and non-cross-linked amphiphilic copolymer

A novel catalyst PWAA, an assembled complex of phosphotungstic acid (H₃PW₁₂O₄₀) and a non-cross-linked copolymer of N-isopropylacrylamide with an ammonium, was developed. It is an amphiphilic, cross-linked, and supramolecular insoluble complex and showed catalytic activity on oxidation with aqueous hydrogen peroxide. PWAA, used in 2.7×10⁻⁵-2.0×10⁻³ mol equiv., catalyzed oxidation of allylic alcohols, amines, and sulfides efficiently. The turnover number (TON) of PWAA reached up to 35,000. PWAA showed a good stability in organic/aqueous media and was reused three to five times.     

钯催化下有机锡化合物的偶联反应在碳-碳键形成过程中的应用

本文述评了最近几年来钯催化的有机锡化合物与有机亲电试剂的交叉偶联反应在有机合成中用于碳-碳键形成的主要研究成果。主要讨论了直接交叉偶联反应,CO或烯键插入的交叉偶联反应和机理。