Synthesis of some new lignans and the mechanism of intramolecular nonphenolic oxidative coupling of aromatic compounds

Treatment of cis-1,4-diaryl-2,3-epoxy butane with 2,3-dichloro-5,6-dicyano-1,4-benzo-quinone(DDQ) in trifluoroacetic acid(TFA) gave dibenzocycloheptadienes by pinacol rearrangement and intramolecular oxidative coupling of the aryl groups. Meanwhile, the benzofuran analogues were also formed by the same method. These new lignans have potent CNS inhibitory activities. It has been proven that the method is particularly useful when applied to the substrates in which the ring substituents are electron donating. The structures of these products were identified by the MS, UV, IR, NMR spectra, and elemental and X-ray crystallographic analyses.     

Synthesis and Characterization of （CH3CH2CH2CH2NH3）2SnBr6

1 INTRODUCTION Recently, the researches on inorganic-organic hy-brid compounds represent an advanced field in mate-rial science[1]. At the molecular level, the combina-tion of two extremely different components providesan avenue to design new hybrid materials as well asthe ability to modulate properties of one or more ofthe components[2～6]. Some attractive properties, suchas efficient luminescence[2～4], ideal thermal and me-chanical stability, interesting magnetic[5], non-linearoptical[…     

Synthesis and crystal structures of π complexes of copper(I) halides with diallyl disulfide 2CuX · DADS (X = Cl, Br; DADS = CH2=CH-CH2-S-S-CH2-CH=CH2)

Compounds 2CuCl · DADS (I) and 2CuBr · DADS (II) (DADS is diallyl disulfide) are prepared by the ac electrochemical synthesis, and their crystal structures are determined. The complexes are isostructural, space group P2₁/n, Z = 4; I: a = 8.995(2) Å, b = 12.541(2) Å, c = 9.644(2) Å, β = 98.74(2)°, V = 1075.3(4) ų, II: a = 9.064(2), b = 12.878(3), c = 9.832(2) Å, β = 98.61(3)°, V = 1134.7(4) ų. In complexes I and II, the tetradentate DADS ligand is chelate-bridging and is coordinated by two crystallographically independent copper atoms of two inorganic Cu₄X₄ fragments. An insignificantly distorted tetrahedral environment of each of the two copper atoms consists of the olefin group, sulfur atom, and two halogen atoms. The complexes are stabilized additionally by the formation of C-H?S hydrogen bonds involved in characteristic seven-membered rings in the structures.     

Synthesis and properties of trifluoromethylating steroid compounds

Trifluoromethyl steroids la,b; 2a,b; 3a,b have been synthesized by starting from estren 3,17-dicarbonyl-3,3-dimethyl ether (4) and dl-18-methyl-2(3)l5(10)-estra-diene-17-carbonyl-3-methyl ether (5),and by using trimthyltrifluoromethylsilane as the trifluoromethylating agent under the catalysis of tetrarnethylam-monium fluoride.The overall yields were 82%,76%; 54%,62%; and 27%,25%,respectively The α-configura tion of trifluoromethyl group of 17-position was determined by X-ray crystal diffraction method Compounds 1a,2a and 3a showed high affinity for rat uterus PRc.The test of biological activities of compounds 1b,2b and 3b is proceeding.     

Synthesis of 2′(S), 3′(R),5′-trihydroxypentyladenine

A synthesis of 2′(S), 3′(R),5-trihydroxypentyladenine (1) from D-ribonic acid γ-lactone (2) is described.     

Cationic Polymerization with Boron Halides. VIII. Synthesis of (CH3)2C = CHCH2-Polyisobutylene-CI Prepolymer and Subsequent Preparation of (CH3)2C = CHCH2-Poly(isobutylene-b-styrene) and (CH3)2C = CHCH2-Poly(isobutylene-b-α-methylstyrene)

Asymmetric telechelic polyisobutylene, α-PIB-ω), carrying the olefinic head group α = (CH₃)₂ C[dbnd]CHCH₂- and tertiary chlorine endgroup ω = -C(CH₃)₂Cl has been synthesized by the use of the (CH₃)₂C[dbnd]CHCH₂Cl/BCl₃ initiating system. Highest yields were obtained by using methylene chloride diluent at about ?50°C. The presence and position of the olefinic head-group was proven by epoxidation/titration and epoxidation/cleavage. The presence and position of a tertiary chlorine endgroup was proven by initiating block polymerization of a second monomer, such as styrene or α-methylstyrene, by using the asymmetric telechelic polyisobutylene prepolymer in conjunction with Et₂AlCl coinitiator. According to I/DP versus 1/[M] plots obtained in model block copolymerization experiments, with the use of the tert-BuCl/Et₂AlCl initiating system at ?30°C, significant chain transfer to monomer occurs during blocking of styrene; however, monomer transfer is negligible during blocking of α-methylstyrene. Thus, under suitable conditions head-functionalized block copolymers (CH₃)₂C[dbnd]CHCH₂-PIB-b-PαMeSt virtually free of homopolymer contaminants can be obtained.     

Novel and effective methods for α-thioalkylation of aromatic compounds

Convenient and effective methods for the introduction of a mathylthiomethyl group and other α-thioalkyl group into aromatic compounds are described.     

Preparation and reactivity of metal-containing monomers 53. Synthesis and stability of a cluster monomer (μ-H)Os3(μ-OCNMe2)(CO)9PPh2CH2CH=CH2 in solution

The stability of the complex (μ-H)Os₃(μ-OCNMe₂)(CO)₉PPh₂CH₂CH=CH₂ (1), which contains a free unsaturated functional group in the terminal ligand PPh₂CH₂CH=CH₂, with respect to isomerization, chelation of the ligand, and other transformations in solutions was examined. No transformations of complex1 were observed in the course of synthesis from (μ-H)Os₃(μ-OCNMe₂)(CO)₉NMe₃ or upon heating in solution. Complex1 as well as complexes (μ-H)Os₃(μ-OCNMe₂)(CO)₉PHPh₂ and (μ-H)Os₃(μ-OCNMe₂)(CO)₉PPh₃, which were formed as admixtures, were isolated in the solid state and identified by¹H,¹H-{³¹P}, and¹H-{¹H} NMR, IR, and Raman spectroscopy and mass spectrometry. For Part 52, see Ref. 1. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1455–1460, August, 2000.     

Synthesis and characterization of β-diketiminate germanium(II) compounds

Reactions of LGeCl (L = CH[C(Me)N(Ar)](2); Ar = 2,6-iPr(2)C(6)H(3)) with KOtBu or LiR (R = 2-thienyl, N(H)Ar, PPh(2)) yielded the germanium(II) compounds LGeR [R = OtBu (1), 2-thienyl (2), N(H)Ar (3), PPh(2) (4)]. The reduction of (2-thienyl)(2)PCl with lithium afforded the diphosphane [(2-thienyl)(2)P](2) (5). The treatment of (2-thienyl)(2)PCl with LiAlH(4) or KHBtBu(3) led to the formation of (2-thienyl)(2)PH (6). The NHC-assisted reaction of LGeCl and 6 resulted in the isolation of LGeP(2-thienyl)(2) (7). This is the first example where NHC is used for eliminating HCl from compounds with P-H and Ge-Cl bonds. All solid products were characterized by elemental analysis, NMR and IR spectroscopy, and single-crystal X-ray structure determination.     

Synthesis and conformation of fluorinated β-peptidic compounds

Experimental and theoretical data indicate that, for α-fluoroamides, the F-C-C(O)-N(H) moiety adopts an antiperiplanar conformation. In addition, a gauche conformation is favoured between the vicinal C-F and C-N(CO) bonds in N-β-fluoroethylamides. This study details the synthesis of a series of fluorinated β-peptides (1-8) designed to use these stereoelectronic effects to control the conformation of β-peptide bonds. X-ray crystal structures of these compounds revealed the expected conformations: with fluorine β to a nitrogen adopting a gauche conformation, and fluorine α to a C=O group adopting an antiperiplanar conformation. Thus, the strategic placement of fluorine can control the conformation of a β-peptide bond, with the possibility of directing the secondary structures of β-peptides.     

Synthesis and properties of antiferroelectric and/or ferroelectric compounds with the –CH2O group close to chirality centre

ABSTRACT

Novel chiral three-ring compounds with the –CH₂O group close to chirality centre were synthesised and their properties were studied. The phase transitions and phase sequences were observed using a polarising optical microscope. The phase transition temperatures and enthalpies were checked by differential scanning calorimetry. A broad-frequency dielectric spectroscopy was also used to confirm the phase transition temperatures as well as the phase sequence. The helical pitch was measured by the spectrophotometry method. It was found that the compounds differing only in one lateral substituted fluorine atom create two different chiral tilted smectic phases, one a ferroelectric phase (SmC*) and the other an antiferroelectric phase (SmC_A*).     

Synthesis of 5′-benzoyl-2′-hydroxychalcones and related flavonoid compounds

Summary 5 -Benzoyl-2 -hydroxychalcones were synthesized by the condensation of 5 -benzoyl-2 -hydroxyacetophenone with aromatic aldehydes in presence of an ethanolic solution of potassium hydroxide. Derivatives of 6-benzoylflavonoids were prepared from chalcones.     

Synthesis of 2′-hydroxychalcones and related compounds in interfacial solid-liquid conditions

A general synthetic method of 2′-hydroxychalcones and 2′-hydroxyphenyl-(2-alkylvynyl) ketones in interfacial solid-liquid conditions, is described. No secondary reactions were observed. The interfacial mechanism is discussed by means of the structure of active sites of solid.     

连续二氧化碳激光敏化氧化CF2HCL,CF2=CF2,CF2=CFCl,CHCl3,CHCl=CCl2和CH2=CH2

本文报道了连续二氧化碳激光敏化氧化CF_2HCl,CF_2==CF_2,CF_2==CFCL,CHCl_3,CHCl==CCl_2和CH_2==CH_2的反应,讨论了某些反应的机制。结果表明,激光敏化方法可以使不能直接吸收激光的反应物分子在气相中发生反应,并有可能产生卡宾。     

Synthesis and acid-base properties of new β-diaminophosphoryl compounds

Russian Journal of Organic Chemistry -     

Synthesis and antibacterial activity of brominated 2′(4′)-nitro-3-hydroxy diphenyl ethers

Eight new brominated 2′(4′)-nitro-3-hydroxy diphenyl ethers have been designed and synthesized.The structures of new compounds were confirmed by ~1H NMR,IR and HRMS.The bioactivity tests showed that these compounds possessed antibacterial activities against the tested bacteria.These new compounds cannot be transformed into dioxins when they were manufactured and used.