FACILE SYNTHESIS OF 4-AMINO-4-DEOXY-4''''-DEMETHYLEPIPODOPHYLLOTOXIN

4-Amino-4-deoxy-4′-demethylepipodophyllotoxin has beendirectly synthesized from 4′-demethylepipodophyllotoxin and HN_3in the presence of BF3·Et_2O,followed by hydrogenation withpalladium on charcoal as catalyst.     

SYNTHESIS OF ASYMMETRIC ETHERS CLEAVAGE OF ACYCLIC ACETALS WITH ZrCl_4-LiAlH_4

In this paper, we investigated the selective cleavage of acyclic acetals with the reagent system, ZrCl_4-LiAlH_4. The results indicate that this system is very useful for the cleavage of acyclic acetals to the corresponding asymmetric ethers.     

A STUDY OF ACYLATION OF AN ENAMINE AND A NOVEL SYNTHESIS OF 4-PYRONES

The acylation of 3-pentanone enamine was studied and a novelformation of 4-pyrones from β-diketone enol esters was found involvingan intramolecular O- to C-acyl shift followed by cyclization.     

SYNTHESIS OF ANALOGUES OF HUPERZINE A 4．THE PREPARATION OF A PYRIMIDONE ANALOGUE OF HUPERZINE A

ＳＹＮＴＨＥＳＩＳＯＦＡＮＡＬＯＧＵＥＳＯＦＨＵＰＥＲＺＩＮＥＡ４．ＴＨＥＰＲＥＰＡＲＡＴＩＯＮＯＦＡＰＹＲＩＭＩＤＯＮＥＡＮＡＬＯＧＵＥＯＦＨＵＰＥＲＺＩＮＥＡ￥ＹｕｎＬｏｎｇＬＩ；ＸｕＣｈａｎｇＨＥａｎｄＤｏｎｇＬｕＢＡＩ（ＳｈａｎｇｈａｉＩｎｓ...     

CHIRAL SYNTHESIS OF LEUKOTRIENE B_4

ＣＨＩＲＡＬ　ＳＹＮＴＨＥＳＩＳ　ＯＦ　ＬＥＵＫＯＴＲＩＥＮＥ　Ｂ＿４ＣＨＩＲＡＬＳＹＮＴＨＥＳＩＳＯＦＬＥＵＫＯＴＲＩＥＮＥＢ＿４￥ＹａｎＦａｎｇＷＡＮＧ；ＪｉｎＣｕｉＬＩ；ＹｕＬｉｎＷＵ；（ＳｔａｔｅｋｅｙＬａｂｏｒａｔｏｒｙｏｆＢｉｏ－ｏｒｇａ...     

C-4 EPIMERIZATION OF α-D-GLUCOPYRANOSIDE: A FACILE SYNTHESIS OF 4-O-ACETYL-α-D-GALACTOPYRANOSYL DERIVATIVES

An unexpected epimerization resulting from the reaction of α-D-glucopyranosyl derivatives with DAST is described. The reaction of 3,4-di-O-acetyl-1,6-di-O-trityl-β-D-fructofuranosyl 2,3,6-tri-O-acetyl-α-D-glucopyranoside (1), methyl 2,3-di-O-acetyl-6-O-trityl-α-D-glucopyranoside (6), 2,3-di-O-acetyl-6-O-trityl-α-D-glucopyranosyl 2,3-di-O-acetyl-6-O-trityl-α-D-glucopyranoside (13), and 2,3-di-O-acetyl-6-O-tert-butyldiphenylsilyl-α-D-glucopyranosyl 2,3,4,6-tetra-O-acetyl-α-D-glucopyranoside (14) with DAST at 0°C did not give the expected C-4 fluorodeoxy galacto derivatives, but instead, the corresponding 4-O-acetyl-3-hydroxy-α-D-galactopyranosides in yields of 52–78%. When the treatment of 6 was carried out at ?25°C for ～5 min the corresponding diastereomeric 4-O-diethylaminosulfinates (9a,b) were isolated as the major products (40%). Evidence suggests that the epimerization reaction most probably resulted from an intramolecular displacement of the intermediate diethylaminosulfur difluoride ester or diethylaminosulfinyl ester by the neighbouring acetoxy groups.     

SYNTHESIS OF (4S)-ETHOXYSILATRANE-4-CARBOXYLIC ACIDS

ＳＹＮＴＨＥＳＩＳＯＦ（４Ｓ）－ＥＴＨＯＸＹＳＩＬＡＴＲＡＮＥ－４－ＣＡＲＢＯＸＹＬＩＣＡＣＩＤＳ￥ＺｈｅｎｇＲｏｎｇＬＵ；ＣｈｕｎＹｕａｎＴＡＯ；ＣｈｕｍＹｕａｎＴＡＯ；ＲｅｎＸｉＺＨＵＯ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ，ＷｕｈａｎＵｎ...     

CONTENTS OF VOLUME 4 February 1995 Volume 4 Number 1

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SYNTHESIS AND CRYSTAL STRUCTURE OF BaGa_4

<正> BaGa4,tetragonal space group I4/mmm with lattice parameters a=b=4.5650(8), c=10.786(2)A, V=224.77(7)A3,Dc=6.15 gcm-3,and Z=2,λ(MoKα)=0.71069A,μ=335.93cm-1,F(OOO) =360. The final R = 0.045, Rw=0.069.The distribution of valence electrons in crystal Ba6a4 is described and a suggestion that two different types of gallium atoms form covalent bonds by utilizing sp3 and dsp3 hybrid orbitals respectively is proposed.     

CRYSTAL STRUCTURES OF ISOMERS OF DIHYDROXYDIBENZO—14—CROWN—4

<正> C18H18O6·H2O, Mr = 348. 34, cis-isomer: orthorhombic, Cmc21, a = 16. 421(3), 6 = 11.978(1), c=8. 624(1)(?), V = 1696. 2(?)3, Z = 4, Dc= 1.293 gcm-3, λ(MoKα) = 0. 71073(?), μ = 0. 911cm-1, F (000) = 763, R = 0. 043, Rw = 0. 042 for 769 unique observed reflections. trans-Isomer : orthorhombic, Cmc21, a = 16. 503(2), b = 12. 297(2), c=8. 557(3) (?). V = 1736(?)3, Z = 4, Dc= 1.271 gem-3, λ(MoKα) = 0. 71073(?), μ = 0. 892cm-1, F (000) = 736, R=0.048, Rw = 0. 046 for 551 unique observed reflections. The configurations of the two molecules appear as butterflies. There is a Cm symmetry in the molecule of each isomer.     

SYNTHESIS AND PHASE BEHAVIOR OF LIQUID CRYSTALLINE 4''''-ALKYLOXY-4-HYDROXYBIPHENYLS

The synthesis and phase behavior of a series of 4'-alkyloxy-4-hydroxy biphenyls were discribed.The effects of reaction conditions onthe yields of products were investigated.The characterizations ofthermotropic liquid crystalline products for the type and thermalproperties are discussed through the use of differential scanningcalorimetry,polarizing microscopy.     

STUDIES ON THERMOSTABILITY OF MODEL MoO_4 TETRAHEDRA

ＳＴＵＤＩＥＳＯＮＴＨＥＲＭＯＳＴＡＢＩＬＩＴＹＯＦＭＯＤＥＬＭｏＯ４ＴＥＴＲＡＨＥＤＲＡＧｕｏＪｉａｎｃｈａｎｇ，ＲｅｎＳｕｚｈｅｎ，ＬｕｏＨｏｎｇｂｏ，ＢａｏＸｉｎｈｅ，ＺｈａｉＲｕｎｓｈｅｎｇ（ＳｔａｔｅＫｅｙＬａｂｏｒａｔｏｒｙｏｆＣａ...     

ABSORPTION SPECTRA OF 4f ELECTRON TRANSITIONS IN THE SYSTEM OF NEODYMIUMSEMIXYLENOL ORANGE-CETYLPYRIDINIUM CHLORIDE

In this paper the absorption spectra of Nd-SXO-CPC complex by 4f electron transitions have been studied by zero-order and fourth-order derivative spectrophotome-try. The molar absorptivity is 2.6×10~3 1.mol~(-1).cm~(-1) at 585 nm, the fourth-order derivative molar absorptivity is 1.4×10~4 1.mol~(-1).cm~(-1) at 584.5(-) and 587(+) nm. They are 300 times and 1600 times greater than those of the chloride, respectively.     

EFFECT OF SOLVENT ON THE COPOLYMERIZATION OF 2,2,6,6-TETRAMETHYL 4-PIPERIDINYL METHACRYLATE WITH STYRENE

The radical copolymerizations of 2,2,6, 6-tetramethyl 4-piperidinyl methacrylate (TMPM) with styrene in various solvents have been studied. The monomer reactivity ratios r_1 and r_2 were determined. It is observed that in all of these reaction systems, there are appreciable solvent effects on both r_1 and r_2, which can be correlated to the difference in chemical shifts of olefinic protons of TMPM. And the variance of the copolymer microstructure in various media was discussed.     

EFFECT OF WATER ON THE CONDUCTIVITY OF PPQ (ClO_4~-) COMPLEX

The preparation of conducting PPQ film was first reported in the previous paper. It is very interesting that this film is highly sensitive to moisture in air. The hydration and dehydration of the film are accompanied by change not only in color but also in conductivity and UV-visible spectrum. The conducting PPQ is reduced to PPQ and loses its conductivity after being soaked in water.     

STUDY OF ELECTROCHEMISTRY OF TETRANUCLEAR MOLYB-DENUM CLUSTER COMPOUND [Mo_4S_4(μ-dtp)_2(dtp)_4]

<正> The electrochemical behavior of tetranuclear molybdenum cluster [Mo4S4 (μ-dtp)2 (dtp)43 (1) (dtp = S2P (OEt)2) has been investigated by cyclic voltammetry, potentiotatic polarization measurement, controlled potential coulometry and pulse polarography. It is demonstrated that the compound undergoes two consecutive near reversible one-electron reductions at 0. 01V and -0. 77V , respectively and a near reversible one-electron oxidation at 1. 01V with scan rates from 25mV/sec to 1V/sec in cyclic voltammetric measurements. The cluster compound displays three redox processes, indicating its high structural stability.     

CRYSTAL AND MOLECULAR STRUCTURE OF COMPLEX OF 1,2-CYCLOHEXYL-12-CROWN-4 WITH EUROPIUM NITRATE

<正> C12H22O4Eu(NO3)3,Mr=568. 28,monoclinic, P21/n,a=7. 980(1) ,6= 17.226(2), c=14. 460(3) A,B=100.15(1) , V= 1956. 6A3,Z=4,Dc=1.929 g/cm3,F(000) = 1128. The structure was sieved by direct methods and Fourier synthesis, and refined by block-diagonal and full matrix least-squares method to a final R of 0. 055 for 2568 independent reflections of I>3a(I). The ten donor oxygen atoms in the crowm ether and NO3 groups are coordinated to central metal ion Eu(III) forming an irregular coordination polyhedron. The Eu(III) ion is out of the ether oxygen plane and the three nitrate groups are bidentately coordinated to the Eu (III) on the opposite side of the polyether. The average bond lengths of Eu-O(NO3) and Eu-O(ether) are 2. 491A and 2. 558A ,respectively.     

SYNTHSIS OF 5-CYANO-2-(4-n-PENTYL-4-BIPHENYLYL)-PYRIMIDINE

Condensation of substituted diethyl-malonates withphenylamidine hydrochloride give liquid crystals with a pyrimidinering,which then subjeet graup transformation to give thetitle compound—5-cyano-2-(4-n-peatyl-4-biphenylyl)pyrimidine in high yield.     

SYNTHESIS AND CRYSTAL STRUCTURE OF WCu_4S_4Cl_2Py_6

<正> Introduction. In recent years, the di-, tetra-. hexa-nuclear mixed metal cluster compounds of tungsten have been studied. In these compounds, more stable (WO_4-nSn)~2- skeleton remains unchanged. So far the penta-, hepta- and other polynuclear cluster compounds of tungsten have not yet been found. We describe here the preparation and structure of a new pentanuclear tungstencopper mixed metal cluster compound WCu_4S_4Cl_2y_6     

PREPARATION AND CHARACTERIZATION OF cis-,4-POLYBUTADIENE CONTAINING A FRACTION OF trans-1,4-POLYBUTADIENE

Polymerization of butadiene catalysed first with V(acac)_3-Al(i-Bu)_2Cl, then with Co(acac)_3-H_2O-Al(i-Bu)_2Cl has been studied. The polymer obtained was identified to be a new variety of cis-1,4-polybutadiene which contained a fraction of trans-1,4-polybutadiene chemically bonded to the cis-1,4-polybutadiene chains. Its molecular weight and trans-1,4 content can be regulated by varying the catalyst composition and concentration as well as other polymerization conditions. The trans-1,4 fraction, although it presents only in 9—16%, forms a crystalline phase in the matrix at room temperature and facilitates the crystallization of the polymer.