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1995 Volume 6 Issue 3
1995, 6(3): 173-176
Abstract:
Low-valent titanium reagent prepared from titanium tetrachloride and zinc in tetrahydrofuran has been used to promote a novel cyclodimerization of α,β-unsaturated ketones,leading to cyclopentanol derivatives(2 and3).A possible reaction mechanism was proposed.
Low-valent titanium reagent prepared from titanium tetrachloride and zinc in tetrahydrofuran has been used to promote a novel cyclodimerization of α,β-unsaturated ketones,leading to cyclopentanol derivatives(2 and3).A possible reaction mechanism was proposed.
1995, 6(3): 177-180
Abstract:
Acid catalyzed rearrangements of 1 and 3 were examined.The olefinic double bond was the most reactive group in protonation reaction.In the absence of olefinic double bond,tert-hydroxy group reacted faster than cyclopropane ring.
Acid catalyzed rearrangements of 1 and 3 were examined.The olefinic double bond was the most reactive group in protonation reaction.In the absence of olefinic double bond,tert-hydroxy group reacted faster than cyclopropane ring.
1995, 6(3): 181-184
Abstract:
The Mannich-type reactions of p-toluenesulfonamide with trichlorophosphine,dichlorophenylphosphine,diethyl phosphite,or triphenylphosphite were studied.The structures of new products were confirmed by 1HNMR,31PNMR,MS,elemental analysis and x-ray diffraction.
The Mannich-type reactions of p-toluenesulfonamide with trichlorophosphine,dichlorophenylphosphine,diethyl phosphite,or triphenylphosphite were studied.The structures of new products were confirmed by 1HNMR,31PNMR,MS,elemental analysis and x-ray diffraction.
1995, 6(3): 185-188
Abstract:
Heterocyclic ketene aminals 1 or 2 reacted with 2,3,4,6-tetra-O-acetyl-a-D-glucopyranosyl bromide using mercuric cyanide-calcium hydride or mercuric cyanide-molecular sieve 4A as catalyst to give the O-glycosidated heterocyclic ketene aminals 3 or 4 in moderate yields.
Heterocyclic ketene aminals 1 or 2 reacted with 2,3,4,6-tetra-O-acetyl-a-D-glucopyranosyl bromide using mercuric cyanide-calcium hydride or mercuric cyanide-molecular sieve 4A as catalyst to give the O-glycosidated heterocyclic ketene aminals 3 or 4 in moderate yields.
1995, 6(3): 189-192
Abstract:
An efficient synthesis of 5,9,13-trimethyl-2-isopropyl-12(S),13(S)-epoxy-14-bromo-2(Z),4(E),8(E)-tetradecatrienenitrile,a key intermediate in the synthesis of antitumor cembranoids including 11,12-epoxy-sarcophytol-A,11,12-epoxysarcophytol-A acetate and 11,12-epoxycembrene-C,was first described through seven step sequence in～32% overall yield from E,E-farnesol.
An efficient synthesis of 5,9,13-trimethyl-2-isopropyl-12(S),13(S)-epoxy-14-bromo-2(Z),4(E),8(E)-tetradecatrienenitrile,a key intermediate in the synthesis of antitumor cembranoids including 11,12-epoxy-sarcophytol-A,11,12-epoxysarcophytol-A acetate and 11,12-epoxycembrene-C,was first described through seven step sequence in～32% overall yield from E,E-farnesol.
SYNTHESIS OF ANALOGUES OF HUPERZINE A 3．THE PREPARATION OF SOME SINGLE RING ANALOGUES OF HUPERZINE A
1995, 6(3): 193-196
Abstract:
Huperzine A(1),an inhibitor of acetylcholinesterase isolated from the clubmoss Huperzia serrata,is used for treatment of Alzheimer's disease.The preparation of four analogues of Hup A,compounds 2,3,4 and 5,was described.Their biological activities were also tested.
Huperzine A(1),an inhibitor of acetylcholinesterase isolated from the clubmoss Huperzia serrata,is used for treatment of Alzheimer's disease.The preparation of four analogues of Hup A,compounds 2,3,4 and 5,was described.Their biological activities were also tested.
1995, 6(3): 197-198
Abstract:
As continuation of our study,6 title compouds were synthesized by condensing 1-aryl-5-mercapto-tetrazoles with 4'-demethyl-epipodophyllotoxin in the presence of CF3COOH(TFA).
As continuation of our study,6 title compouds were synthesized by condensing 1-aryl-5-mercapto-tetrazoles with 4'-demethyl-epipodophyllotoxin in the presence of CF3COOH(TFA).
1995, 6(3): 199-200
Abstract:
C60 reacts with 2-aminoethylhydrogensulfate to give a mixtore of mono-and bispiperazine fullerene adducts C60(C4H8N2)1-2 and a water-soluble f'ullerene derivative C60Hn(NHCH2CH2OSO3Na)n.
C60 reacts with 2-aminoethylhydrogensulfate to give a mixtore of mono-and bispiperazine fullerene adducts C60(C4H8N2)1-2 and a water-soluble f'ullerene derivative C60Hn(NHCH2CH2OSO3Na)n.
1995, 6(3): 201-204
Abstract:
C60 undergoes 1,3-dipolar cycloaddition reaction with the 1,3-dipole derived from heating 4-hydroxy-L-proline and paraformaldehyde to form a monoadduct in yield of 29.3%.
C60 undergoes 1,3-dipolar cycloaddition reaction with the 1,3-dipole derived from heating 4-hydroxy-L-proline and paraformaldehyde to form a monoadduct in yield of 29.3%.
1995, 6(3): 205-208
Abstract:
The title compounds 3a-3n were prepared with high yields via the reaction of 4-methylphenoxyacetyl chloride with various substituted aromatic amines under the condition of liquid-liquid phase transfer catalysis using polyethylene glycol-400 as catalyst.
The title compounds 3a-3n were prepared with high yields via the reaction of 4-methylphenoxyacetyl chloride with various substituted aromatic amines under the condition of liquid-liquid phase transfer catalysis using polyethylene glycol-400 as catalyst.
1995, 6(3): 209-210
Abstract:
In the presence of phosphoryl group,N-(O,O-diisopropyl)phosphoryl threonine reacted with nucleosides to give both nucleotides and peptides.The result might give some clue to the prebiotic formation of nucleic acids and proteins.
In the presence of phosphoryl group,N-(O,O-diisopropyl)phosphoryl threonine reacted with nucleosides to give both nucleotides and peptides.The result might give some clue to the prebiotic formation of nucleic acids and proteins.
1995, 6(3): 211-214
Abstract:
When DIPP-HIS was incubated in water,citrate buffer,DMF and other mixed solvents,phosphoryl dipeptide,tripeptide even tetrapeptide were found.When DIPP-HIS was incubated with aspartic acid under the same condition.cross dipeptide were found.
When DIPP-HIS was incubated in water,citrate buffer,DMF and other mixed solvents,phosphoryl dipeptide,tripeptide even tetrapeptide were found.When DIPP-HIS was incubated with aspartic acid under the same condition.cross dipeptide were found.
1995, 6(3): 215-216
Abstract:
Under the action of near-visible and UV light,[W10O32]4- undergoes one and two electrons photoreduction to oxidize organic compounds.In homogeneous systems and in the presence of excess of oxygen,photooxidation of alcohols,amine,cyclic hydrocarbon and alkyl benzenes catalyzed by decatungstates have been studied.
Under the action of near-visible and UV light,[W10O32]4- undergoes one and two electrons photoreduction to oxidize organic compounds.In homogeneous systems and in the presence of excess of oxygen,photooxidation of alcohols,amine,cyclic hydrocarbon and alkyl benzenes catalyzed by decatungstates have been studied.
1995, 6(3): 217-220
Abstract:
A new lignan,neoarctin A,has been isolated from the seeds of Arctium lappa L.,and the structure elucidated on the basis of spectral analyais.
A new lignan,neoarctin A,has been isolated from the seeds of Arctium lappa L.,and the structure elucidated on the basis of spectral analyais.
1995, 6(3): 221-224
Abstract:
A new medicagenic acid saponin named asterbatanoside J was isolated from the roots of Aster batangensis.On the basis of chemical and spectral studies especially 2D NMR including COSY,HETCOR,HOHAHA,ROESY and HMBC techniques,its structure has been established as 3-O-β-D-glucopyranosyl-(1,6)-β-D-glucopyranosyl-2β,3β-dihydroxy-olean-12-en-23α.28-dioic acid-28-O-α-L-arabinopyranosyl-(1,3)-α-L-rhamnopyranosyl-(1,2)-β-D-fucopyranoside.
A new medicagenic acid saponin named asterbatanoside J was isolated from the roots of Aster batangensis.On the basis of chemical and spectral studies especially 2D NMR including COSY,HETCOR,HOHAHA,ROESY and HMBC techniques,its structure has been established as 3-O-β-D-glucopyranosyl-(1,6)-β-D-glucopyranosyl-2β,3β-dihydroxy-olean-12-en-23α.28-dioic acid-28-O-α-L-arabinopyranosyl-(1,3)-α-L-rhamnopyranosyl-(1,2)-β-D-fucopyranoside.
1995, 6(3): 225-228
Abstract:
A new taxoid,taxayuntin G,was isolated from the leaves and stems of Taxus yunnanensis.Its structure was elucidated by spectroscopic methods(MS,1H-NMR,13C-NMR,1H-1H COSY,1H-13C COSY,NOE and HMBC).
A new taxoid,taxayuntin G,was isolated from the leaves and stems of Taxus yunnanensis.Its structure was elucidated by spectroscopic methods(MS,1H-NMR,13C-NMR,1H-1H COSY,1H-13C COSY,NOE and HMBC).
1995, 6(3): 229-230
Abstract:
Two new β-dihydroagarofuran sesquiterpenes were isolated from Celastrus orbiculatus,their strutures were elucidated as 1α,2α,8β-triacetoxy-9β-cinnamoyloxy-β-dihydro agarofuran(1)and 1α,2α-diacetoxy-6β-benzoyloxy-9β-cinnamoyloxy-β-dihydroagarofuran(2)mainly by spectroscopic methods.
Two new β-dihydroagarofuran sesquiterpenes were isolated from Celastrus orbiculatus,their strutures were elucidated as 1α,2α,8β-triacetoxy-9β-cinnamoyloxy-β-dihydro agarofuran(1)and 1α,2α-diacetoxy-6β-benzoyloxy-9β-cinnamoyloxy-β-dihydroagarofuran(2)mainly by spectroscopic methods.
1995, 6(3): 231-234
Abstract:
The reaction between Ru(phen)32-(phen=phenanthroline)and Ce(Ⅳ) produces luminescence in aqueous solution.The effect of oxalate concentration on the intensity of chemiluminescence(CL)emission was firstly studied.CL intensity was linearly related to concentration of oxalate over the range of 3.0×10-8-2.9×10-6 mol/L.The detection limit was 1.5×10-8mol/L.The present paper reports this novel CL method for determination of oxalate,which is usually determined by electrogenerated chemiluminescence method.The method was evaluated by carrying out interference study with common ions and some co-existing compounds in human urine,by a recovery study and by the analysis of oxalate in human urine.The results obtained compared well with reference values.
The reaction between Ru(phen)32-(phen=phenanthroline)and Ce(Ⅳ) produces luminescence in aqueous solution.The effect of oxalate concentration on the intensity of chemiluminescence(CL)emission was firstly studied.CL intensity was linearly related to concentration of oxalate over the range of 3.0×10-8-2.9×10-6 mol/L.The detection limit was 1.5×10-8mol/L.The present paper reports this novel CL method for determination of oxalate,which is usually determined by electrogenerated chemiluminescence method.The method was evaluated by carrying out interference study with common ions and some co-existing compounds in human urine,by a recovery study and by the analysis of oxalate in human urine.The results obtained compared well with reference values.
1995, 6(3): 235-238
Abstract:
An automated flow-injection-stopped-flow micellar enhanced Spectrofluorimetric method for determination of L-ascorbic acid(AA)is described.The method is based on the interference of laccase by AA.causing a decrease in the rate of the laccase-catalysed fluorescence reaction in the presence of Brij-35.The resulting change of fluorescence intensity at em 530nm(ex 430nm)is proportional to the concentration of AA with the linear range over 0.2 to 2.0μg/ml.The significant interference from ferric and cupric ions can be eliminated by addition of ED-TA.The method has been applied to the determination of AA in pharmaceuticals.the results agree well with the nominal values and those obtained by the reference method.The recovery of AA in pharmaceuticals are between 91.5% and 115.4%.
An automated flow-injection-stopped-flow micellar enhanced Spectrofluorimetric method for determination of L-ascorbic acid(AA)is described.The method is based on the interference of laccase by AA.causing a decrease in the rate of the laccase-catalysed fluorescence reaction in the presence of Brij-35.The resulting change of fluorescence intensity at em 530nm(ex 430nm)is proportional to the concentration of AA with the linear range over 0.2 to 2.0μg/ml.The significant interference from ferric and cupric ions can be eliminated by addition of ED-TA.The method has been applied to the determination of AA in pharmaceuticals.the results agree well with the nominal values and those obtained by the reference method.The recovery of AA in pharmaceuticals are between 91.5% and 115.4%.
1995, 6(3): 239-242
Abstract:
The dioxygen species was characterized and their thermostability was investigated on BaF2-LaOF catalyst by means of in situ Raman spectroscopy in the temperature range of 298K to 1023K.It is found that there exist mainly the O2 2-ions and a little amount of O22-(1 < n < 1)ions at the temperature for OCM(1023K)on BaF2-LaOF catalyst in O2 stream.These dioxygen species can be expected to be the active sites for OCM.
The dioxygen species was characterized and their thermostability was investigated on BaF2-LaOF catalyst by means of in situ Raman spectroscopy in the temperature range of 298K to 1023K.It is found that there exist mainly the O2 2-ions and a little amount of O22-(1 < n < 1)ions at the temperature for OCM(1023K)on BaF2-LaOF catalyst in O2 stream.These dioxygen species can be expected to be the active sites for OCM.
1995, 6(3): 243-246
Abstract:
It is reported that the As(Ⅲ)scavenging bromine reaction rate constant can be determined by means of measuring the limiting current of a rotating disk electrode(RDE).The As(Ⅲ)scavenging bromine second order reaction rate constants in sulfuric acid are 3.6×105Lmol-1·s-1 at 20℃ and 8.9×105 Lmol-1s-1 at 41℃ respectively.The activation energy is 33 KJ·mol-1.The results shows that.As(Ⅲ)can be used as scavenging etchant of bromine in submicronieter and three-dimension lithography.
It is reported that the As(Ⅲ)scavenging bromine reaction rate constant can be determined by means of measuring the limiting current of a rotating disk electrode(RDE).The As(Ⅲ)scavenging bromine second order reaction rate constants in sulfuric acid are 3.6×105Lmol-1·s-1 at 20℃ and 8.9×105 Lmol-1s-1 at 41℃ respectively.The activation energy is 33 KJ·mol-1.The results shows that.As(Ⅲ)can be used as scavenging etchant of bromine in submicronieter and three-dimension lithography.
1995, 6(3): 247-250
Abstract:
Synthesis of a new family of charge transfer complexes-tetramethylthiotetrathiafulvalene-C60Brn)(TMT-TTF-C60Brn,n=6,24) is described.The charge transfer in complexes was investigated by UV electronic absorption spectra.The pressure-area isotherm showed that TMT-TTF-C60Brn) could form stable monolayers at the air-water interface.
Synthesis of a new family of charge transfer complexes-tetramethylthiotetrathiafulvalene-C60Brn)(TMT-TTF-C60Brn,n=6,24) is described.The charge transfer in complexes was investigated by UV electronic absorption spectra.The pressure-area isotherm showed that TMT-TTF-C60Brn) could form stable monolayers at the air-water interface.
1995, 6(3): 251-254
Abstract:
Photovoltage properties and charge transfer process of tailed porphyrin Mn(Ⅲ) complex,meso-mono-[o-(4-diethylamino)butyramidophenyl] triphenyl porphyrin Mn(Ⅲ)(MDBPTPPMn(Ⅲ)Cl)were investigated by surface photovoltage spectrum(SPS) and field modulation surface photovoltage spectrum(FMSPS).Furthermore,its absorption spectra in near-ultraviolet and near-infrared that have been disputed are given a new assignment in this paper.
Photovoltage properties and charge transfer process of tailed porphyrin Mn(Ⅲ) complex,meso-mono-[o-(4-diethylamino)butyramidophenyl] triphenyl porphyrin Mn(Ⅲ)(MDBPTPPMn(Ⅲ)Cl)were investigated by surface photovoltage spectrum(SPS) and field modulation surface photovoltage spectrum(FMSPS).Furthermore,its absorption spectra in near-ultraviolet and near-infrared that have been disputed are given a new assignment in this paper.
1995, 6(3): 255-258
Abstract:
A new natural polymeric catalyst,silica-supported carboxymethyl cellulose platinum complex(abbr.as SiO2-CMC-Pt)has been found to catalyze the hydrogenation of ethyl benzoate to ethyl cyclohexanecarboxylate in about 100% yield at 60-70℃ and 1 atm of hydrogen pressure.The turnover number could amount to 925 when reacted for 42 h without deactivation of the catalyst.
A new natural polymeric catalyst,silica-supported carboxymethyl cellulose platinum complex(abbr.as SiO2-CMC-Pt)has been found to catalyze the hydrogenation of ethyl benzoate to ethyl cyclohexanecarboxylate in about 100% yield at 60-70℃ and 1 atm of hydrogen pressure.The turnover number could amount to 925 when reacted for 42 h without deactivation of the catalyst.
1995, 6(3): 259-260
Abstract:
Tris(tropolonato)samarium(Ⅲ)has been prepared in high yield,by the electrochemical oxidation of samarium metal anode in acetonitrile solution of 2-hydroxy-2,4,6-cycloheptatrienone(tropolone,HL).The unusual divalent samarium(Ⅱ)complex was formed at the first step of electrosynthesis.The final product,Sm(C7H3O3)3,has been characterized by microanalysis and the studies of IR and 1H,13C NMR spectra.
Tris(tropolonato)samarium(Ⅲ)has been prepared in high yield,by the electrochemical oxidation of samarium metal anode in acetonitrile solution of 2-hydroxy-2,4,6-cycloheptatrienone(tropolone,HL).The unusual divalent samarium(Ⅱ)complex was formed at the first step of electrosynthesis.The final product,Sm(C7H3O3)3,has been characterized by microanalysis and the studies of IR and 1H,13C NMR spectra.
1995, 6(3): 261-260
Abstract:
Heterobimetallic complexes in which chromium and lanthanide metals were bridged with difunctional benzyloxide group:(Cp2LnOCH2C6H5)Cr(CO)3(Ln=Gd,Dy,Yb,Y),were synthesized The complexes were characterized by elemental analysis,IR and 1HNMR spectroscopy.
Heterobimetallic complexes in which chromium and lanthanide metals were bridged with difunctional benzyloxide group:(Cp2LnOCH2C6H5)Cr(CO)3(Ln=Gd,Dy,Yb,Y),were synthesized The complexes were characterized by elemental analysis,IR and 1HNMR spectroscopy.
1995, 6(3): 263-264
Abstract:
MoS4Cu2Ag(Ph3P)3Br·H2O,fw=1344,triclinic,space group P1:a=13.246(4),b=20.314(6),c=11.995(4)Å,α=93.25(3)°,β=115.99(2)°,γ=74.44(3)°,V=2788.(2)Å3,Z=2,Dc=1.60g cm-3,F(000)=1340,μc=22.87cm-1,R=0.060,RW=0.067.This is the first example of tetranuclear M-Mo-S cluster containing Cu and Ag together and the structure is a completed cubane that the Br atom bonds to Cu and Ag.
MoS4Cu2Ag(Ph3P)3Br·H2O,fw=1344,triclinic,space group P1:a=13.246(4),b=20.314(6),c=11.995(4)Å,α=93.25(3)°,β=115.99(2)°,γ=74.44(3)°,V=2788.(2)Å3,Z=2,Dc=1.60g cm-3,F(000)=1340,μc=22.87cm-1,R=0.060,RW=0.067.This is the first example of tetranuclear M-Mo-S cluster containing Cu and Ag together and the structure is a completed cubane that the Br atom bonds to Cu and Ag.
1995, 6(3): 265-266
Abstract:
A dimeric Keggin-type polyoxotungstate β-Ge2W18Ti6O7714 has been synthesized from the lacunary precursor β-GeW6O3410 and characterized by means of elemental anajysis,IR,polarogram,183W NMR and FAB mass spectroscopy.The 183W NMR spectrum consists of two lines with intensity ratio 1:2 as expected for trisubstiluted heteropolyanion.With the help of FAB mass spectrum,we concluded that it is a dimer of two Keggin units with D30 symmetry.
A dimeric Keggin-type polyoxotungstate β-Ge2W18Ti6O7714 has been synthesized from the lacunary precursor β-GeW6O3410 and characterized by means of elemental anajysis,IR,polarogram,183W NMR and FAB mass spectroscopy.The 183W NMR spectrum consists of two lines with intensity ratio 1:2 as expected for trisubstiluted heteropolyanion.With the help of FAB mass spectrum,we concluded that it is a dimer of two Keggin units with D30 symmetry.
