Login In
1995 Volume 6 Issue 8
1995, 6(8): 645-646
Abstract:
The ozonization of 4-isopropylidenepentacyclo(5.4.0.02,6.03,10.05,9)undecane-8, 11-dione 1 and the reductive cleavage of the ozonide 2 formed with different reagents are described.
The ozonization of 4-isopropylidenepentacyclo(5.4.0.02,6.03,10.05,9)undecane-8, 11-dione 1 and the reductive cleavage of the ozonide 2 formed with different reagents are described.
1995, 6(8): 647-650
Abstract:
The Sharpless asymmetric epoxidation of 1 was carried out to give the (1S, 2S)-4 in 33% yield, which was protodesilylated, giving (-)-5 with 50% ee.The steric effect of phenyl group on silicon upon the rate and ee of the reaction was observed.The possibility of kinetic resolution of racemic silanol under the Sharpless reaction condition was examined.
The Sharpless asymmetric epoxidation of 1 was carried out to give the (1S, 2S)-4 in 33% yield, which was protodesilylated, giving (-)-5 with 50% ee.The steric effect of phenyl group on silicon upon the rate and ee of the reaction was observed.The possibility of kinetic resolution of racemic silanol under the Sharpless reaction condition was examined.
1995, 6(8): 651-652
Abstract:
Treatment of N-cyanomethyl quaternary ammonium salts with NaH in tetrahydrofuran gave the desired ring enlargement products via the ylide.One of the products was subjected to reduction by sodium borohydride for the removal of the CN group.
Treatment of N-cyanomethyl quaternary ammonium salts with NaH in tetrahydrofuran gave the desired ring enlargement products via the ylide.One of the products was subjected to reduction by sodium borohydride for the removal of the CN group.
THECHEMICAL SELECTTVE ADDITION OF GRIGNARD REAGENT TO α-CINNAMOYL KETENE(1, 2-ETHYLENE)DITHIOACETALS
1995, 6(8): 653-654
Abstract:
The addition reaction of Grignard reagents to α-cinnamoyl ketene (1, 2-ethylene) dithioacetals 4 was examined.The results showed that the 1, 4-manner nucleophilic attack at the cinnamoyl carbon carbon double bond occurred.Possible mechanism about the reaction selectivity is disenssed.
The addition reaction of Grignard reagents to α-cinnamoyl ketene (1, 2-ethylene) dithioacetals 4 was examined.The results showed that the 1, 4-manner nucleophilic attack at the cinnamoyl carbon carbon double bond occurred.Possible mechanism about the reaction selectivity is disenssed.
1995, 6(8): 655-656
Abstract:
A novel isonucleoside, 2, 5-anhydro-4-(adenine-9-yl-)-L-iditol was synthesized from D-glucose through 9 steps.
A novel isonucleoside, 2, 5-anhydro-4-(adenine-9-yl-)-L-iditol was synthesized from D-glucose through 9 steps.
1995, 6(8): 657-660
Abstract:
Nimbidiol 1 and epi-6-oxonimbidioi 2 have been efficiently and stereospecifically synthesized from 3-isopropoxy-5, 5-dimethyl-2-cyclohexenone and iodide 3 which are readily available.
Nimbidiol 1 and epi-6-oxonimbidioi 2 have been efficiently and stereospecifically synthesized from 3-isopropoxy-5, 5-dimethyl-2-cyclohexenone and iodide 3 which are readily available.
1995, 6(8): 661-662
Abstract:
The newly isolated purine alkaloid, an open chain nucleoside-ganoderpurine natural product, was synthesized by the Michael addition of adenine to mesityl oxide.
The newly isolated purine alkaloid, an open chain nucleoside-ganoderpurine natural product, was synthesized by the Michael addition of adenine to mesityl oxide.
1995, 6(8): 663-666
Abstract:
Six new compounds——steroid-oligopeptide were designed and synthesized with active ester method, their structures (CA-G1, DCA-G1, CA-G2, DCA-G2, CA-G3, DCA-G3)were confirmed by spectra and elemental analysis.Preliminary study on their bioactivities showed that the DCA-G3 has the ability of acid-inhibition and the others have the ability of promoting acid-secretion.The metabolic time of six title compounds are longer than the positive control(Boc-G2).
Six new compounds——steroid-oligopeptide were designed and synthesized with active ester method, their structures (CA-G1, DCA-G1, CA-G2, DCA-G2, CA-G3, DCA-G3)were confirmed by spectra and elemental analysis.Preliminary study on their bioactivities showed that the DCA-G3 has the ability of acid-inhibition and the others have the ability of promoting acid-secretion.The metabolic time of six title compounds are longer than the positive control(Boc-G2).
1995, 6(8): 667-668
Abstract:
The linear hexapeptide(His-Gly-Asp-Ser-Gly-Asp) was synthesized on solid support.FM group was used for α carboxyl protection group at Aspl.Peptide was cyclized by BOP reagent while still attached to the solid support BOP procedure proceeded more rapidly and gave purer product than DCC/HOBt method.
The linear hexapeptide(His-Gly-Asp-Ser-Gly-Asp) was synthesized on solid support.FM group was used for α carboxyl protection group at Aspl.Peptide was cyclized by BOP reagent while still attached to the solid support BOP procedure proceeded more rapidly and gave purer product than DCC/HOBt method.
1995, 6(8): 669-672
Abstract:
We have synthesized the title compounds (1) and (2).The structure of regioisomer (4).a new acyclic nucleotide, was determined by spectroscopic methods(1H-NMR.13C-NMR, 13C-1H HMBC).A by-product(7) was also isolated and identified using 1H-NMR, MS and spot tests.Antiviral activity were evaluated.
We have synthesized the title compounds (1) and (2).The structure of regioisomer (4).a new acyclic nucleotide, was determined by spectroscopic methods(1H-NMR.13C-NMR, 13C-1H HMBC).A by-product(7) was also isolated and identified using 1H-NMR, MS and spot tests.Antiviral activity were evaluated.
1995, 6(8): 673-674
Abstract:
The preparation of the α carboxyl 9-fluorenylmethyl(FM) ester of Boc-aspartic acid is described.This new protected amino acid linked to the polymeric support by β carboxyl group offers a convenient strategy for the synthesis of head-to-tail cyclopeptides while the peptides remained attached to the polymeric support.
The preparation of the α carboxyl 9-fluorenylmethyl(FM) ester of Boc-aspartic acid is described.This new protected amino acid linked to the polymeric support by β carboxyl group offers a convenient strategy for the synthesis of head-to-tail cyclopeptides while the peptides remained attached to the polymeric support.
1995, 6(8): 675-678
Abstract:
A novel triterpene of protostane type, alizexol A(1).the first compound of this class having a substituted tetrahydropyran ring.has been isolated from the rhizome of Alisma orientalis (Sam) Juzep The structure was elucidated by spectral data.and the ring conformation was analyzed by NOESY experiment.
A novel triterpene of protostane type, alizexol A(1).the first compound of this class having a substituted tetrahydropyran ring.has been isolated from the rhizome of Alisma orientalis (Sam) Juzep The structure was elucidated by spectral data.and the ring conformation was analyzed by NOESY experiment.
1995, 6(8): 679-680
Abstract:
A new sesquiterpenoid named as celastrine was isolated from the seed oil of Celastrus flagellaris Rupr.Its structure was determined as 1α, 6β, 8α, 13-tetraacetoxy-9α-benzoyloxy-β-dihydroagarofuran by UV, IR, MS and NMR(1H NMR, 13C NMR, 1H-1H COSY, 1H-13C COSY, NOESY and HMBC) spectra.
A new sesquiterpenoid named as celastrine was isolated from the seed oil of Celastrus flagellaris Rupr.Its structure was determined as 1α, 6β, 8α, 13-tetraacetoxy-9α-benzoyloxy-β-dihydroagarofuran by UV, IR, MS and NMR(1H NMR, 13C NMR, 1H-1H COSY, 1H-13C COSY, NOESY and HMBC) spectra.
1995, 6(8): 681-682
Abstract:
A new cyclopeptidc designated as vaccarin A were isolated from the seeds of Vaccaria segetalis.Its structure was obtained by spectral evidence.
A new cyclopeptidc designated as vaccarin A were isolated from the seeds of Vaccaria segetalis.Its structure was obtained by spectral evidence.
1995, 6(8): 683-686
Abstract:
The structure of gnetifolin A, previously proposed as (1), was revised to (2) on the basis of the original spectra of gnetifolin A and the spectral data of its synthetic analogs.
The structure of gnetifolin A, previously proposed as (1), was revised to (2) on the basis of the original spectra of gnetifolin A and the spectral data of its synthetic analogs.
1995, 6(8): 687-690
Abstract:
The inclusion complexation of sodium 2, 2-dimethyl-silapentane-5-sulphonate (DSS) with β-cyclodextrin has been studied by means of NMR spectroscopy.The association constant (Ka) and thus the free energy change (-△G0) were determined to be 89.5 L/mol and 11.4 kJ/mol, respectively.
The inclusion complexation of sodium 2, 2-dimethyl-silapentane-5-sulphonate (DSS) with β-cyclodextrin has been studied by means of NMR spectroscopy.The association constant (Ka) and thus the free energy change (-△G0) were determined to be 89.5 L/mol and 11.4 kJ/mol, respectively.
1995, 6(8): 691-694
Abstract:
Molecular mechanical and quantum chemical methods were used to calculate the conformational and electronic structures of the template molecules of (nitro substituted anilino)-4-substituted-2, 6-piperazinediones.With the calculation results we explained the acylation reactivity of title compounds satisfactorily.
Molecular mechanical and quantum chemical methods were used to calculate the conformational and electronic structures of the template molecules of (nitro substituted anilino)-4-substituted-2, 6-piperazinediones.With the calculation results we explained the acylation reactivity of title compounds satisfactorily.
1995, 6(8): 695-698
Abstract:
AMI method has been used to study the reaction of ozone with ethylene. The activation energies of every route in each step are given.
AMI method has been used to study the reaction of ozone with ethylene. The activation energies of every route in each step are given.
1995, 6(8): 699-700
Abstract:
The electroanalytical characteristics of methaqualone are reported in this paper.A sensitive single sweep voltammetrie procedure for trace methaqualone was developed, the detection limit being 9.0×10-5 mol·L-1.
The electroanalytical characteristics of methaqualone are reported in this paper.A sensitive single sweep voltammetrie procedure for trace methaqualone was developed, the detection limit being 9.0×10-5 mol·L-1.
1995, 6(8): 701-704
Abstract:
A new rapid and accurate method for determining inosine by capillary zone electrophoresis (CZE) is presented.The electrophoresis separation was performed at 24℃ in a fused-silica capillary(51.2cm×50μmi.d., 38.5cm to UV detector) using 20mmol/L borax-20mmol/L H3PO4(pH 8.5) as the background electrolyte at 24KV applied voltage.Inosine samples were led into the capillary electrokinetically at 10KV for 15 seconds.In the range of 20μg/mL to 300μg/mL, inosine can be quantitatively determined with a detection limit of 2.1μg/mL and a RSD of 2.92%.Hypoxanthine was used as the internal standard.
A new rapid and accurate method for determining inosine by capillary zone electrophoresis (CZE) is presented.The electrophoresis separation was performed at 24℃ in a fused-silica capillary(51.2cm×50μmi.d., 38.5cm to UV detector) using 20mmol/L borax-20mmol/L H3PO4(pH 8.5) as the background electrolyte at 24KV applied voltage.Inosine samples were led into the capillary electrokinetically at 10KV for 15 seconds.In the range of 20μg/mL to 300μg/mL, inosine can be quantitatively determined with a detection limit of 2.1μg/mL and a RSD of 2.92%.Hypoxanthine was used as the internal standard.
1995, 6(8): 705-706
Abstract:
Vitamin B1 reacts with diazo-aminobenzene sulfonic acid to form a red complex in a basic medium and there is absorption of vitamin B2 at 440 nm.A flow injection spectrophotometric determination of the two medicaments is described based on these characteristics.The method was simple and had a high selectivity and sampling rate of 60 h-1 The dynamic linear ranges were 0-100μg ml-1 of vitamin B1 and 0-80μg ml-1 of vitamin B2, respectively.The relative standard deviation was 0.2881% (n=10) for vitamin B1.
Vitamin B1 reacts with diazo-aminobenzene sulfonic acid to form a red complex in a basic medium and there is absorption of vitamin B2 at 440 nm.A flow injection spectrophotometric determination of the two medicaments is described based on these characteristics.The method was simple and had a high selectivity and sampling rate of 60 h-1 The dynamic linear ranges were 0-100μg ml-1 of vitamin B1 and 0-80μg ml-1 of vitamin B2, respectively.The relative standard deviation was 0.2881% (n=10) for vitamin B1.
1995, 6(8): 707-710
Abstract:
The electrochemical behaviors of boron-doped diamond film electrodes grown selectively with 4×4mm2 in size have been studied using cyclic voltammetry and potentiostatic method.The diamond electrode exhibits adequate electrochemical activity and the response current changes linearly with K3Fe(CN)6 concentrations.The response current is proportional to the square root of scan rate, reflecting that mass transport was controlled by planar diffusion.Stable mass transport was quickly established within 4 seconds.Good stability and reproducibility are attractive properties of the diamond electrode for sensor applications.
The electrochemical behaviors of boron-doped diamond film electrodes grown selectively with 4×4mm2 in size have been studied using cyclic voltammetry and potentiostatic method.The diamond electrode exhibits adequate electrochemical activity and the response current changes linearly with K3Fe(CN)6 concentrations.The response current is proportional to the square root of scan rate, reflecting that mass transport was controlled by planar diffusion.Stable mass transport was quickly established within 4 seconds.Good stability and reproducibility are attractive properties of the diamond electrode for sensor applications.
SYNTHESES AND PROPERTIES OF POLY(N-ISOPROPYLACRYLAMIDECO-N-ACRYLOXYSUCCINIMIDE)AND ITS IgG-CONJUGATE
1995, 6(8): 711-712
Abstract:
A series of copolymers of N-isopropylacrylamide and N-acryloxysuccinimide with different active ester contents and different molecular weights and their conjugates with IgG were prepared.The properties of copolymers and IgG-bearing polymers were studied.
A series of copolymers of N-isopropylacrylamide and N-acryloxysuccinimide with different active ester contents and different molecular weights and their conjugates with IgG were prepared.The properties of copolymers and IgG-bearing polymers were studied.
1995, 6(8): 713-714
Abstract:
The complex of quaternary ammonium halide and hydrogen halide was found to be the very efficient catalyst in the rapid cleavage and esterification of benzyl alkyl ethers with carboxylic acids under microwave irradiation.
The complex of quaternary ammonium halide and hydrogen halide was found to be the very efficient catalyst in the rapid cleavage and esterification of benzyl alkyl ethers with carboxylic acids under microwave irradiation.
1995, 6(8): 715-718
Abstract:
The OCM reaction was studied on BaF2-LaOF catalyst and the results show that CH4 can be effectively activated and selectively converted to C2+.Under the reaction conditions of GHSV=15000h-1 and reaction temperature 1044K, the high C2+ yield of 20.66% with CH4, conversion of 33.08% and C2+ selectivity of 62.47% was obtained at CH4:O2=3:1, and the high C2+ selectivity of 84.55% with CH4 conversion of 16.54% was obtained at CH4:O2=9:1.XRD results suggest that tetragonal LaOF is the active phase in BaF2-LaOF catalyst.
The OCM reaction was studied on BaF2-LaOF catalyst and the results show that CH4 can be effectively activated and selectively converted to C2+.Under the reaction conditions of GHSV=15000h-1 and reaction temperature 1044K, the high C2+ yield of 20.66% with CH4, conversion of 33.08% and C2+ selectivity of 62.47% was obtained at CH4:O2=3:1, and the high C2+ selectivity of 84.55% with CH4 conversion of 16.54% was obtained at CH4:O2=9:1.XRD results suggest that tetragonal LaOF is the active phase in BaF2-LaOF catalyst.
1995, 6(8): 719-722
Abstract:
Layered double hydroxides (LDHs) pillared with heteropolyoxometalate have been synthesized via both restructuring of hydrotalcite-like compounds and direct anion exchange under microwave field.LDHs and their derivatives are both found to be efficient for alkylation of isobutane with butene with a higher butene conversion and selectivity towards C8o.
Layered double hydroxides (LDHs) pillared with heteropolyoxometalate have been synthesized via both restructuring of hydrotalcite-like compounds and direct anion exchange under microwave field.LDHs and their derivatives are both found to be efficient for alkylation of isobutane with butene with a higher butene conversion and selectivity towards C8o.
1995, 6(8): 723-726
Abstract:
The intensity of the signal(g=1.974) resulted from Zr3+ ion on the surface of ZrO2 catalyst, increased with the calcination temperature and time, but that of the signal (g=2.003) resulted from Fs+ centers (surface oxygen ion vacancies with a single trapped electron) decreased and finally disappeared at 550℃.
The intensity of the signal(g=1.974) resulted from Zr3+ ion on the surface of ZrO2 catalyst, increased with the calcination temperature and time, but that of the signal (g=2.003) resulted from Fs+ centers (surface oxygen ion vacancies with a single trapped electron) decreased and finally disappeared at 550℃.
1995, 6(8): 727-730
Abstract:
In situ FTIR spectra have been used to characterize surface oxygen adspecies on 20%SrF2/La2O3 catalyst used for the oxidative coupling of methane (OCM).The O2- surface superoxide with characteristic vibration frequency at 1113-1123 cm-1 was formed on the sample after treatment with H2 at 700℃ following exposure to O2 at temperatures between 650℃ and 25℃, The O2- adspecies could also be detected on the working sample at 650℃ and might play an important role in the OCM reaction leading to the production of C2H4 from CH4.These results provide evidence that superoxide ions may be the active oxygen on 20%SrF2/La2O3 catalyst during the oxidative coupling of methane.
In situ FTIR spectra have been used to characterize surface oxygen adspecies on 20%SrF2/La2O3 catalyst used for the oxidative coupling of methane (OCM).The O2- surface superoxide with characteristic vibration frequency at 1113-1123 cm-1 was formed on the sample after treatment with H2 at 700℃ following exposure to O2 at temperatures between 650℃ and 25℃, The O2- adspecies could also be detected on the working sample at 650℃ and might play an important role in the OCM reaction leading to the production of C2H4 from CH4.These results provide evidence that superoxide ions may be the active oxygen on 20%SrF2/La2O3 catalyst during the oxidative coupling of methane.
1995, 6(8): 731-734
Abstract:
The compound barium(Ⅱ) tetraphenylborate, Ba(Bph4)2·4H2O has been prepared, and its decomposition mechanism was studied by TG and DTA.The thermal decomposition products were examined by gas chromatography and chemical methods.Kinetic analysis for the first stage of thermal decomposition process was obtained by TG-DTG curves and kinetic parameters were obtained from analysis of the TG-DTG curves with integral and differential methods.The most probable kinetic function was suggested by comparison of kinetic parameters.Mathematical expression for the kinetic compensation effect was derived.
The compound barium(Ⅱ) tetraphenylborate, Ba(Bph4)2·4H2O has been prepared, and its decomposition mechanism was studied by TG and DTA.The thermal decomposition products were examined by gas chromatography and chemical methods.Kinetic analysis for the first stage of thermal decomposition process was obtained by TG-DTG curves and kinetic parameters were obtained from analysis of the TG-DTG curves with integral and differential methods.The most probable kinetic function was suggested by comparison of kinetic parameters.Mathematical expression for the kinetic compensation effect was derived.
1995, 6(8): 735-738
Abstract:
Superfine powders of alkali metal hydrides of nanometric size exhibit very high reactivity in the hydrogenolysis of aryl halides.
Superfine powders of alkali metal hydrides of nanometric size exhibit very high reactivity in the hydrogenolysis of aryl halides.
