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1999 Volume 10 Issue 12
1999, 10(12): 983-986
Abstract:
The alkylation of phenol with methanol was studied and a high selectivity for Oalkylation was attained over alkali-metal cation-exchanged X zeolites. The transformation of primary products of the title reaction was also studied over CsX zeolite. On the basis of experimental results, a reaction scheme on CsX zeolite was suggested
The alkylation of phenol with methanol was studied and a high selectivity for Oalkylation was attained over alkali-metal cation-exchanged X zeolites. The transformation of primary products of the title reaction was also studied over CsX zeolite. On the basis of experimental results, a reaction scheme on CsX zeolite was suggested
1999, 10(12): 983-986
Abstract:
Treatment with Sm-CdCl2-HMPA system, dibenzyl and diphenyl diselenides react with acyl halides and acid anhydrides in one-pot to give corresponding selenoesters in good yields under mild and neutral conditions.
Treatment with Sm-CdCl2-HMPA system, dibenzyl and diphenyl diselenides react with acyl halides and acid anhydrides in one-pot to give corresponding selenoesters in good yields under mild and neutral conditions.
1999, 10(12): 987-988
Abstract:
Resorcarens la-b (R'=Ph, p-MeOC6H4) Were fully alkylated with alkyl iodides or bromides in TEBA/KOH/DMF solid-liquid PTC process with 63-82% yields. whereas the three calix[4]pyrroles 3a-b (2R=2Me, (CH2)4 (CH2)5) were alkylated with alkyl iodides in TBAB/50%NaOH/CH2Cl2 liquid-liquid PTC system with lower yields (10-38%).
Resorcarens la-b (R'=Ph, p-MeOC6H4) Were fully alkylated with alkyl iodides or bromides in TEBA/KOH/DMF solid-liquid PTC process with 63-82% yields. whereas the three calix[4]pyrroles 3a-b (2R=2Me, (CH2)4 (CH2)5) were alkylated with alkyl iodides in TBAB/50%NaOH/CH2Cl2 liquid-liquid PTC system with lower yields (10-38%).
1999, 10(12): 989-990
Abstract:
The oxidation on 1,4-substituted Hantzsch 1,4-dihydropyridines with nitrosonium tetrafluorohorate (NO+BF4-) in acetonitrile gave Hantzsch pyridines in good yields. In some cases the dealkylation occurred. The evidences to draw the mechanism were presented.
The oxidation on 1,4-substituted Hantzsch 1,4-dihydropyridines with nitrosonium tetrafluorohorate (NO+BF4-) in acetonitrile gave Hantzsch pyridines in good yields. In some cases the dealkylation occurred. The evidences to draw the mechanism were presented.
1999, 10(12): 991-994
Abstract:
The Schiff base cryptand and its cryptates were synthesized with the methods of [1+1] condensation of trialdehyde and tris(2-aminoethyl)amine and obtained in 60-65%, 5-25% and 70-80% yields respectively with or without some rare earth elements as templates. The polyoxa-aza cryptand was produced in 72% and 60-70% yields with reduction of Schiff base and its cryptates respectively.
The Schiff base cryptand and its cryptates were synthesized with the methods of [1+1] condensation of trialdehyde and tris(2-aminoethyl)amine and obtained in 60-65%, 5-25% and 70-80% yields respectively with or without some rare earth elements as templates. The polyoxa-aza cryptand was produced in 72% and 60-70% yields with reduction of Schiff base and its cryptates respectively.
1999, 10(12): 995-998
Abstract:
The tittle compound has been synthesized successfully through the efficient and selective functional transformation of α-santonin This procedure is the first successful approach developed for synthesis of the dihydroagarofuran kind of sesquiterpenoids from the eduesmanolide sesquiterpenoid α-santonin.
The tittle compound has been synthesized successfully through the efficient and selective functional transformation of α-santonin This procedure is the first successful approach developed for synthesis of the dihydroagarofuran kind of sesquiterpenoids from the eduesmanolide sesquiterpenoid α-santonin.
1999, 10(12): 999-1002
Abstract:
Three 4β-(1,2,3-triazol-l-y1) podophyllotoxins 2~4 have been synthesized and tested for their antitumor activity in vitro. The compound 3 was found to be much more cytotoxic than the clinically used etoposide (VP-16) against L1210 cells.
Three 4β-(1,2,3-triazol-l-y1) podophyllotoxins 2~4 have been synthesized and tested for their antitumor activity in vitro. The compound 3 was found to be much more cytotoxic than the clinically used etoposide (VP-16) against L1210 cells.
1999, 10(12): 1003-1006
Abstract:
Three single chain amphiphilic cholesterol derivatives with amino acid as hydrophilic groups,Ⅰ, Ⅱ and Ⅲ, were synthesized. When they were hydrated in water, they can all form lamellae structures as evidenced by DSC measurement. The lamellae states of Ⅱ and Ⅲ can be converted to vesicles upon ultrasonication of the diluted aqueous solutions. The vesicles showed very slow release rate of the encapsulated water-soluble dyes, indicating that they are stable and belong to the least permeable vesicles.
Three single chain amphiphilic cholesterol derivatives with amino acid as hydrophilic groups,Ⅰ, Ⅱ and Ⅲ, were synthesized. When they were hydrated in water, they can all form lamellae structures as evidenced by DSC measurement. The lamellae states of Ⅱ and Ⅲ can be converted to vesicles upon ultrasonication of the diluted aqueous solutions. The vesicles showed very slow release rate of the encapsulated water-soluble dyes, indicating that they are stable and belong to the least permeable vesicles.
1999, 10(12): 1007-1012
Abstract:
The reactions of the bis (dimethylamino) alkylarsine with diols lead to the formations of macrocyclic arsinous acid esters. The synthesis of title compounds was described and their structures were characterized by elemental analysis, IR, 1HNMR, and MS.
The reactions of the bis (dimethylamino) alkylarsine with diols lead to the formations of macrocyclic arsinous acid esters. The synthesis of title compounds was described and their structures were characterized by elemental analysis, IR, 1HNMR, and MS.
1999, 10(12): 1013-1014
Abstract:
A novel heterocyclic poly (aryl ether ketone ketone) (PPEKK) containing cyclohexene ring was prepared from 1-methyl-cyclohex-l-ene-4,5-diyl-bis(4-chlorophenyl methanone) and 4-(4-hydroxyphenyl)(2H) phthalazin-l-one. The polymer was characterized by FTIR, 1HNMR, DSC, TG and X-ray analysis
A novel heterocyclic poly (aryl ether ketone ketone) (PPEKK) containing cyclohexene ring was prepared from 1-methyl-cyclohex-l-ene-4,5-diyl-bis(4-chlorophenyl methanone) and 4-(4-hydroxyphenyl)(2H) phthalazin-l-one. The polymer was characterized by FTIR, 1HNMR, DSC, TG and X-ray analysis
1999, 10(12): 1015-1018
Abstract:
A new type of anthracene crown ether 1,8-anthraceno-l8-crown-5 has been synthesized and the photophysical properties upon complexation with alkali and alkaline-earth metal cations were investigated.The fluorescence quantum yield and lifetime are appreciably enhanced, and the stability constant Ks were determined by fluorometric titration. It was found that the magnitude of Ks is controlled by the size and charge density of the complexed cations.
A new type of anthracene crown ether 1,8-anthraceno-l8-crown-5 has been synthesized and the photophysical properties upon complexation with alkali and alkaline-earth metal cations were investigated.The fluorescence quantum yield and lifetime are appreciably enhanced, and the stability constant Ks were determined by fluorometric titration. It was found that the magnitude of Ks is controlled by the size and charge density of the complexed cations.
1999, 10(12): 1019-1022
Abstract:
The synthesis and upconverted fluorescent properties of three novel organic compounds with the structure:donor/bridge/acceptor are reported. The dyes show strong upconverted fluorescence.
The synthesis and upconverted fluorescent properties of three novel organic compounds with the structure:donor/bridge/acceptor are reported. The dyes show strong upconverted fluorescence.
1999, 10(12): 1023-1026
Abstract:
Two new diterpenoid glucosides，cleroserroside A and cleroserroside B, were isolated from the aerial parts of Clerodendrum serratum var. amplexifolium Moldenke. Their structures were characterized by spectral and chemical methods.
Two new diterpenoid glucosides，cleroserroside A and cleroserroside B, were isolated from the aerial parts of Clerodendrum serratum var. amplexifolium Moldenke. Their structures were characterized by spectral and chemical methods.
1999, 10(12): 1027-1028
Abstract:
A minor new diterpenoid alkaloid, soulidine, was isolated from the roots of Delphinium Souliei Franch, its structure was established on the basis of spectral evidences.
A minor new diterpenoid alkaloid, soulidine, was isolated from the roots of Delphinium Souliei Franch, its structure was established on the basis of spectral evidences.
1999, 10(12): 1029-1030
Abstract:
Phytochemical re-investigation of Coleus xanthanthus led to the isolation and identification of a novel sesquiterpenoid 1, named as 4,5,11-trimethyl-8,9-seco-1(10),7(11)-eremophiladien-8,12-o1id-9-oic acid. The structure of 1 was elucidated by modern spectroscopic methods, especially by X-ray diffraction.
Phytochemical re-investigation of Coleus xanthanthus led to the isolation and identification of a novel sesquiterpenoid 1, named as 4,5,11-trimethyl-8,9-seco-1(10),7(11)-eremophiladien-8,12-o1id-9-oic acid. The structure of 1 was elucidated by modern spectroscopic methods, especially by X-ray diffraction.
1999, 10(12): 1031-1034
Abstract:
Three new triterpenoid saponins, escins IVg (1), IVh (2) and VIb (3) were isolated from the seeds of Aesculus chinensis along with two known saponins, escin Ⅲa (4) and desacylescin I (5). Their structures were elucidated by spectroscopic analysis and chemical hydrolysis.
Three new triterpenoid saponins, escins IVg (1), IVh (2) and VIb (3) were isolated from the seeds of Aesculus chinensis along with two known saponins, escin Ⅲa (4) and desacylescin I (5). Their structures were elucidated by spectroscopic analysis and chemical hydrolysis.
1999, 10(12): 1035-1036
Abstract:
A new triterpenoid saponin, tomentoside (5), together with prosapogenin CP 4 (1), huzhangoside B (2), C (3) and D (4) was isolated from the ethanolic extract ofAnemone tomentosa. Its structure was established by spectroscopic and chemical evidence.
A new triterpenoid saponin, tomentoside (5), together with prosapogenin CP 4 (1), huzhangoside B (2), C (3) and D (4) was isolated from the ethanolic extract ofAnemone tomentosa. Its structure was established by spectroscopic and chemical evidence.
1999, 10(12): 1037-1040
Abstract:
From Psammosilene tunicoides W. C. Wu et C. Y. Wu, two cyclic octapeptides (named psammosilenins A and B) were isolated. Their structures were determined as cyclo(-Pro1-Phe1-Pro2-Phe2-Phe2-Ala-Pro3-Leu-) and cyclo(-Pro1-Gly-Phe1-Val-Pro2-Phe2-Thr-Ile-) by spectroscopic methods.
From Psammosilene tunicoides W. C. Wu et C. Y. Wu, two cyclic octapeptides (named psammosilenins A and B) were isolated. Their structures were determined as cyclo(-Pro1-Phe1-Pro2-Phe2-Phe2-Ala-Pro3-Leu-) and cyclo(-Pro1-Gly-Phe1-Val-Pro2-Phe2-Thr-Ile-) by spectroscopic methods.
1999, 10(12): 1041-1044
Abstract:
The spectophotometry of charge transfer (CT) complexes of tetrachloro-p-benzoquinone (TCB) with tertiary amine [triethylamine (TEA), triphylamine (TPA), N,N-dimethylphenylamine (DMPA), N-ethylcarbazole (ECZ)] have been studied in dichloromethane in L1V-visible region. The CT complexes parameter, molar ratio of reactants in complex, molar extinction coefficient εCT, equilibrium constant KCT, free energy 0G and dissociation energy of the CT complex excited state E, have also been estimated and discussed.
The spectophotometry of charge transfer (CT) complexes of tetrachloro-p-benzoquinone (TCB) with tertiary amine [triethylamine (TEA), triphylamine (TPA), N,N-dimethylphenylamine (DMPA), N-ethylcarbazole (ECZ)] have been studied in dichloromethane in L1V-visible region. The CT complexes parameter, molar ratio of reactants in complex, molar extinction coefficient εCT, equilibrium constant KCT, free energy 0G and dissociation energy of the CT complex excited state E, have also been estimated and discussed.
1999, 10(12): 1045-1048
Abstract:
A series of new dansylamide derivatives have been synthesized and the specific binding affinity of such fluorophores to nucleic acids has been investigated by using absorption, circular dichroism (CD), fluorescence and atomic force microscopy (AFM) The results indicate that the positive charge of the ligand and the π-π stacking between the dansyl part of the ligand and the DNA base pair may play an important role when binding to polynucleotides.
A series of new dansylamide derivatives have been synthesized and the specific binding affinity of such fluorophores to nucleic acids has been investigated by using absorption, circular dichroism (CD), fluorescence and atomic force microscopy (AFM) The results indicate that the positive charge of the ligand and the π-π stacking between the dansyl part of the ligand and the DNA base pair may play an important role when binding to polynucleotides.
1999, 10(12): 1049-1050
Abstract:
By means of XPS, a new O1s peak which reflects the lattice oxygen on A2BO4-type compounds is discovered, suggesting that the lattice oxygen might have two energy states on this type of material.
By means of XPS, a new O1s peak which reflects the lattice oxygen on A2BO4-type compounds is discovered, suggesting that the lattice oxygen might have two energy states on this type of material.
1999, 10(12): 1051-1052
Abstract:
The enthalpy of reaction for the decomposition of monoclinic ammonium paratungstate, (NH4)10H2W12O424H2O(s), was measured using a HT-1000 calorimeter. From the experimental results, the standard enthalpy of formation of ammonium paratungstate at 298.15 K is obtained.
The enthalpy of reaction for the decomposition of monoclinic ammonium paratungstate, (NH4)10H2W12O424H2O(s), was measured using a HT-1000 calorimeter. From the experimental results, the standard enthalpy of formation of ammonium paratungstate at 298.15 K is obtained.
1999, 10(12): 1053-1056
Abstract:
This study involves initial Hartree-Fock and Density Functional theory calculations on the molecular recognition of the cyclodextrins. The α-cyclodextrin-acetophenone complexation system was investigated with PM3, HF/3-21G* and B3LYP/3-21G* methods. The results indicated that the inclusion orientation in which the acetyl group of the acetophenone points towards the secondary hydroxyls of the α-cyclodextrin was preferable in energy. The steric effect was supposed as the physical reason of such a behavior. Hence, the simple rule the anti-parallel arrangement of the dipoles of the host and guest molecules in the cyclodextrin complexation is not generally applicable.
This study involves initial Hartree-Fock and Density Functional theory calculations on the molecular recognition of the cyclodextrins. The α-cyclodextrin-acetophenone complexation system was investigated with PM3, HF/3-21G* and B3LYP/3-21G* methods. The results indicated that the inclusion orientation in which the acetyl group of the acetophenone points towards the secondary hydroxyls of the α-cyclodextrin was preferable in energy. The steric effect was supposed as the physical reason of such a behavior. Hence, the simple rule the anti-parallel arrangement of the dipoles of the host and guest molecules in the cyclodextrin complexation is not generally applicable.
1999, 10(12): 1057-1060
Abstract:
An electrochemical quartz crystal impedance system has been applied to monitor generation of precipitate and adsorption of the precipitate onto Au electrode during electrochmical oxidation and Fe(CN)63-/Fe(CN)64- electrochemical catalytic oxidation of L-cysteine in phosphate aqueous buffer (pH 7.4). Significant decreases in the resonant frequency and increases in the motional resistance and the static capacitance were found during the precipitate adsorption, and the frequency shift found in solution was ca. 2 times that in air. Similar responses of quartz crystal impedance and a white precipitate were obtained during redox titration of L-cysteine solution using K3Fe(CN)6 solution. FT-IR analysis indicated that the white precipitate is cystine. The electrode collection efficiency of the electrogenerated cystine was estimated.
An electrochemical quartz crystal impedance system has been applied to monitor generation of precipitate and adsorption of the precipitate onto Au electrode during electrochmical oxidation and Fe(CN)63-/Fe(CN)64- electrochemical catalytic oxidation of L-cysteine in phosphate aqueous buffer (pH 7.4). Significant decreases in the resonant frequency and increases in the motional resistance and the static capacitance were found during the precipitate adsorption, and the frequency shift found in solution was ca. 2 times that in air. Similar responses of quartz crystal impedance and a white precipitate were obtained during redox titration of L-cysteine solution using K3Fe(CN)6 solution. FT-IR analysis indicated that the white precipitate is cystine. The electrode collection efficiency of the electrogenerated cystine was estimated.
