SYNTHESIS OF 2-(TRIMETHYLSILYL)ETHYL α-d-MANNOPYRANOSIDES REVISITED

Glycosylation of 2-(trimethylsilyl)ethanol with various ethyl 1-thioglycosides, which were activated with N-iodosuccinimide and silver triflate, was studied. The starting thioglycosides, some prepared for the first time, were obtained conventionally from the corresponding α-1-acetates. When β-1-acetates were more readily available, these were converted to the α-anomers by anomerization, prior to the glycosylation. Using ethyl 1-thioglycosides as glycosyl donors, especially those bearing a pivaloyl or a nonparticipating group at O-2, the corresponding 2-(trimethylsilyl)ethyl α-d-mannopyranosides were obtained in excellent yields.     

SYNTHESIS AND POLYMERIZATION KINETICS OF 1-BROMOMETHYL-7,7-DIMETHYLBICYCLO[2.2.1]HEPT-2-YL ACRYLATE

Starting from camphene and NBS the 1-bromomethyl-7, 7-dimethylblcyclo-[2.2.1]hept-2-yl acrylate [BMCHA] has been synthesized by two steps. The polymerization kinetics equation of this monomer was obtained as follows: Rp=K[BPO]~(0.50)[BMCHA]~(1.0) and the apparent activation energy of the polymerization was evaluated to be 82.96KJ/mol.     

BICYCLO[2. 2. 1] HEPT-5-ENE-2,3-DICARBOXYLIC ANHYDRIDE CAPPED ‘PMR'''' TYPE POLYAMIDE-IMIDE

The resin solution of NA capped ‘PMR' type polyamide-imide was prepared from bicyclo [2.2.1]-hept-5-ene-2, 3-dicarboxylic acid ethyl ester,1, 2, 4-trimellitic acid-2-(or-1-) ethyl ester and 4,4'-methylenedianiline in ethanol. This resin solution is specially suitable for the preparation of compo-sites. The fiexural strength of the glass cloth reinforced plastics was 6000--7000 kg/cm~2 (RM) and4000--kg/cm~2 (260°--300℃), respectively. The result of isothermal aging for 800 hours in-dicated that this composite can be used at 26℃. The mechanism of the formation of polyamide-imide was discussed by using appropriate model compounds.     

CRYSTAL STRUCTURE OF 1-METHYL-6-(E-ETHOXYCAR-BONYLVINYL)-8-BENZOYL-2, 3-DIHYDRO-1H-IMIDAZO[1, 2-a] PYRIDIN-5-ONE

<正> The title compound C20H20N2O4(Mr=352.39)belongs to mono-clinic space group C2/c with a=9.208(4),b=11.714(3),c=32.336(8)A,β=100.83(2)°,V=7146.2(6)A3,Z=16,Dc=1.35 g/cm3,μ(Moka)=1.03 cm-1 and final R=0.06 for 1781 reflections with F≥2.5(F).There are two independent molecules in an asymmetric unit.Neither pyridinone nor phenyl ring is coplanar with the ketonic carbonyl group in the molecule.     

SYNTHESIS OF DIALKYL 2-(1-CYANO-2-OXO-1-PHENYL-ALKYL)-3-(TRIPHENYL-λ5-PHOSPHANYLIDENE)-SUCCINATES

3-Oxo-2-phenyl-butanenitrile or 3-oxo-2-phenyl-pentanenitrile undergo a smooth reaction with dialkyl acetylenedicarboxylates in the presence of triphenylphosphine to produce highly-functionalized salt-free ylides in nearly quantitative yields. These stabilized phosphorus ylides exist as a mixture of two geometrical isomers as a result of restricted rotation around the carbon-carbon partial double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group.     

SYNTHESIS OF ETHYL ACETATE OVER HZSM—5 CATALYST(Ⅰ)

A study on the esterification of ethanol with acetic acid on the HZSM—5 zeolite catalyst ina fixed bed reactor was reported.The influence of the kaolin level and the hydrothermal treatment ofthe catalyst,and also the effect of the reaction conditions,such as the reaction temperature,the molarratio of acid/alcohol and the liquid hour space velocity(LHSV)on the catalytic performance weredetermined.     

SYNTHESIS, CHARACTERIZATION OF 2-[2-(3-NITRO-4-METHOXYLPHENYL) VINYLI-1-ME

ＳＹＮＴＨＥＳＩＳ，ＣＨＡＲＡＣＴＥＲＩＺＡＴＩＯＮＯＦ２－［２－（３－ＮＩＴＲＯ－４－ＭＥＴＨＯＸＹＬＰＨＥＮＹＬ）ＶＩＮＹＬＩ－１－ＭＥＴＨＹＬＰＹＲＩＤＩＮＩＵＭＰＥＮＴＡＡＮＤＨＥＸＡＮＩＴＲＡＴＯＲＡＲＥＥＡＲＴＨ（Ⅲ）ＣＯＭＰＬＥＸＥＳＨ...     

ETHYL 4-(DIETHOXYPHOSPHINYL)-3-OXOBUTANOATE: SELECTIVE SYNTHESIS OF β-KETO PHOSPHONATES

ABSTRACT

The selective synthesis of ethyl 4-(diethoxyphosphinyl)-3-oxobutanoate (7) and the utilization of its trimethylsilyl enolether (14) in a tandem desilylation Horner-Wittig condensation is illustrated.     

Reaction of (±)-7,7-dichloro-4-(1-methylethylidene)-bicyclo[3.2.0]hept-2-en-6-one with ozone

The reaction of (±)-7,7-dichloro-4-(1-methylethylidene)bicyclo[3.2.0]hept-2-en-6-one with ozone involves mainly the exocyclic double bond, and subsequent unusual transformations of ozonides thus formed lead to anomalous products.     

SYNTHESIS AND STRUCTURE OF (Et_4N)_2[Ni_2(OSC_5H_4)_2(μ-SC_6H_4OH)_2]

<正> The synthesis and structure of cluster compound(Et4N)2[Ni2-(OSC6H4)2(u-SC6H4OH)2] are reported. Mr = 876.54,space group P21/n, a = 9.179(4), b = 17.487(6), c = 12.840(4) A;B=92.87(3)°;V=2058.6(2)A3; Z = 2; DC = 1.182g·cm-3.     

SYNTHESIS AND STRUCTURE OF A MIXED-VALENCE HEXAMOLYBDENUM COMPLEX [Et_4N]_2[Mo_6O_(19)H_4]

A hexamolybdenum complex, [Et_4N]_2[Mo_6O_(19)H_4] crystal, withpentavalent and hexavalent molybdenum has been obtained in the solution ofDMF and CH_3OH as organic solvents using MoCl_5 as a starting material. Thecrystallographic parameters obtained by X-ray diffraction analysis are:crthorhombic, a=10. 757(3), b=10. 763(2), c=14. 238(4)A, =1648. 9A~3; Z=2; spacegroup Pnnm; final R=0. 047; final Rw=0. 051~(**)     

SYNTHESIS AND STRUCTURE OF (Et_4N) [Fe_4S_4 (Et_2NCS_2)_4 ]

<正> INTRODUCTION. The Fe_4S_4 cubane-like clusters have been extensively studied as the model compounds for the active center of the Fe-S proteins in the last fifteen years. Coucouvains et al. have recently reported the syntheses and structures of a few Fe_4S_4 cluster compounds containing R_2NCS_2(R_2dtc) and RS (or Cl) mixed terminal ligands and having [Fe_4S_4]~(2+) core oxi-     

4-(4-Chlorophenyl)-3,7,7-trimethyl-1-[2-(4-nitrobenzoyl)ethyl]-4,7,8,9-tetrahydro-1H-pyrazolo[3,4-b]quinolin-5(6H)-one–ethanol (1/1)

Molecules of the title compound, C₂₈H₂₇ClN₄O₄·C₂H₆O, form a C(6) chain via an N—H⋯O hydrogen bond along the c axis by the operation of a c-glide plane, with N⋯O = 2.761 (3) Å and N—H⋯O = 165°. The mol­ecules are further linked by a weak C—H⋯O interaction, with C⋯O = 3.344 (4) Å and C—H⋯O = 150°. Pendant hydrogen-bonded ethanol solvent mol­ecules are attached to the chains by O—H⋯N hydrogen bonds, with O⋯N = 2.904 (3) Å and O—H⋯N = 175°.     

DERIVATIVES OF 4-CHLORO-3,5-DINITROBENZO-TRIFLUORIDE. IV. SYNTHESIS OF BIS [6-(ETHYLTHIO)-5-NITRO-α,α,α-TRIFLUORO-m-TOLYL] DISULFIDE (1) AND ETHYL 2,6-DINITRO-α,α,α-TRIFLUORO-p-TOLYL SULFIDE (2)

Abstract

The reaction of potassium ethyl dithiocarbonate with 4-chloro-3,5-dinitrobenzotrifluoride in dimethylformamide at 25–30°C afforded the titled disulfide (1) and sulfide (2). Possible mechanism and supporting NMR, ir, Raman and mass spectral data are discussed. The assigned structure for 1 was verified by X-ray crystal structure analysis.     

SYNTHESIS AND STRUCTURE OF TETRANUCLEAR MOLYBDENUM CLUSTER COMPOUND[Mo_4S_4(μ-O_2CC_6H_5)_2(dtp)_4]

The cluster compound[Mo_4S_4(μ-O_2CC_5H_5)_2(dtp)_4](dtp=S_2P(OEt)_2)wasobtained by the ligand substitution reaction of tetranuclear molybdenum cluster[Mo_4S_4(μ-dtp)_2(dtp)_4]in the mixed solvent of acetone,ethanol and water in thepresence of C_6H_5CO_2Na.It is monoclinic and crystallizes in space group C2/c,Mr=1495.09,a=12.175(5),b=22.01(1),c=20.875(9),β=99.04(4)°;V=5575(5);Z=4;Dc=1.78g/cm~3.Final R factor is 0.066.The result reveals that the[Mo_4S_4]clustercore and t-(dtp)~(-1)ligands are retained and only μ-bridged(dtp)~(-1)ligands aresubstituted by(C_6H_5CO_2)~(-1)in the substitution reaction,thus producing the newtitle cluster compound,the structure of which contains two species of bidentateligand.     

STUDIES OF SYNTHESIS, STRUCTURE AND PROPERTIES OF CLUSTER COMPOUND [Fe_6S_9(SCH_2CH_2OH)Cl]~(4-)

By mixing appropriate quantity of FeCl_2, (NH_4)_2MoS_4 ano HSCH_2CH_2OH in MeOH--MeONa, the crystal [(C_2H_5)_4N]_4[Fe_6S_9(SCH_2CH_2OH)Cl] was obtained. The cluster compound crystallizes in triclinic, space gtoup, P1, and crystal cell constants:a = 12.818(4)A, b = 13.632(3)A, c = 18.328(7)A, α = 106.09(2)°, β = 100.75(2)°, γ = 102.69(2)°, Z = 2. On the basis of 7517 unique data (I>3σ(I)) the structure has been refined toR = 0.0818 by the block-diagonal least-squares. The result of structure analysis shows thatthe cluster compound [Fe_6S_9(SCH_2CH_2OH)CI]~(4-) includes doubly bridging μ_2-S, triply bridgingμ_3-S and quadruply bridging μ_4-S. The [Fe_6S_9]~(2-) core of [Fe_6S_9(SCH_2CH_2OH)CI]~(4-) consistsof eight nonplanar Fe_2S_3 rhombs that are fused edge-sharing to give four Fe(μ_2-S)(μ_3-S)Fe,two Fe(μ_2--S)(μ_4-S)Fe and two Fe(μ_3-S) (μ_4-S)Fe subunits. The quantum chemical calcu-lation of EHMO method was carried out for this cluster compound. The structure analysisgives a rule wit     

SYNTHESIS AND STRUCTURE OF HEXAKIS CDI-μ-(4-CHLORO-BENZYLTHIO ) NICKEL ] TRITETRACHLOROMETHANE SOL-VATE, [Ni(SCH_2C_6H_4Cl-p)_2]_6 · 3CC1_4

<正> C_(86)H_(72)Cl_(20)Ni_6S_(12) , Mr = 2551. 62, monoclinic, space group C2/c, crystal data: a = 30. 322(5), b=14. 168(3), c=26. 453(4) A ,β=101. 00(4)°, V = 11155. 6 A3, Z=4, Dx=1. 519 g/cm3, λ(MoKα) = 0. 71069 A ,μ=17. 370 cm-1, F(000) = 5152, T = 293 K, final R = 0. 078, Rw = 0. 086 for 5610 (I>3σ(I)) reflections. The crystal is composed of discrete [Ni (SCH2C6H4Cl-p)2]6 and CCl4 solvent molecules. The coordination geometries of the Ni atoms are perfect planes sharing S...S edges. The six NiS4 squares are linked with each other forming a hexagonal prism. The p-ClC6H4CH2S- side chains in the molecule are arranged in the axial and equatorial positions alternately with respect to the pseudo-hexagonal axis of the molecule.     

SYNTHESIS OF 1-(TRIPHENYLGERM YLPROPIONO)-4-SUBSTITUTED THIOSEMICARBAZIDES

ＳＹＮＴＨＥＳＩＳＯＦ１－（ＴＲＩＰＨＥＮＹＬＧＥＲＭＹＬＰＲＯＰＩＯＮＯ）－４－ＳＵＢＳＴＩＴＵＴＥＤＴＨＩＯＳＥＭＩＣＡＲＢＡＺＩＤＥＳ￥ＲｕＹｕＣＨＥＮ；ＰｅｎｇＦｕＬｌ（ＩｎｓｔｌｔｕｔｅｏｆＥｌｅｍｅｎｔｏ－ＯｒｇａｎｉｃＣｈｅｍｉｔｒｙ，...     

STRUCTURE OF CHLORO [2-2''''-PYRIDYL)-6-MSTHYLBEHZOTHIAZOLE] PYROCATECHOLATOANTIMONY(Ⅲ)

<正> C19H14N2O2ClSSb,Mr = 491.6, space group P1, a = 5.977(1), b= 8.708(1), c = 8.962(1) X, a=93.91(1),B= 103.25(1),r=94.80(1), V = 450.6 A3, Z = 1, Do = 1.79, DC = 1.812 g.cm-3,F(000) = 242,u(MoKa)= 18.1 cm-1,R=0.024 for 2903 reflections. The Sb atom is situated in a distorted square- pyramidal ( octahedral) environment, with Sb-Cl 2.546(2), Sb-0 2.004(2)/2.038(3), and Sb-N 2.442(3)/2.526(3)A.     

SYNTHESIS AND CRYSTAL STRUCTURE OF A MOLYBDENUM-COPPER-SULFUR CLUSTER COMPLEX WITH DITHIOBENZOATE LIGAND [Bu_4N]_2[MoCu_2S_4(C_6H_5CS_2)_2]

<正> The title compound has been synthesized by the reaction of (Bu4N)2MoS4, CuCl and (C6H5CS2)(Bu4N) in DMF and recrystallized from DMF/ Et2O. The red black crystal belongs to the triclinic space group P1 with a = 12. 021 (6), b = 17.045(8), c=17. 136(7)(?) , α=110.05(3), β=108.64(4), γ=103.87 (4)°, V = 2873(3)(?)3, Dc=1. 321gcm-3, Z = 2. The structure was refined to R = 0. 065 for .4783 reflections. The anion of the title compound can be described as a MoS42- tetrahedron coordinated by two [Cu(C6H5CS2)] units with the three metal atoms lying on a line. The coordination number of each Cu atom is three.