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2009 Volume 20 Issue 6
2009, 20(6): 635-639
doi: 10.1016/j.cclet.2009.02.011
Abstract:
A new method for preparing (2Z, 4Z, 6Z)-4,5-diethyloxepinedicarboxylate by one-step is described. The synthesis of several oxepines and azepines derivatives was carried out by the reaction of substituted furans or pyrroles with diethyl acetylenedicarboxylate in boiling toluene. The effect factors for this reaction were discussed and reaction condition was optimized.
A new method for preparing (2Z, 4Z, 6Z)-4,5-diethyloxepinedicarboxylate by one-step is described. The synthesis of several oxepines and azepines derivatives was carried out by the reaction of substituted furans or pyrroles with diethyl acetylenedicarboxylate in boiling toluene. The effect factors for this reaction were discussed and reaction condition was optimized.
2009, 20(6): 640-642
doi: 10.1016/j.cclet.2009.01.019
Abstract:
A one-step procedure is developed to synthesize inherently chiral p-tert-butylcalix[4]azacrown 1 through etherification between p-tert-butylcalix[4]arene and compound 3, which can be amplified to efficiently prepare more inherently chiral calix[4]arenes in ABHH substitution pattern.
A one-step procedure is developed to synthesize inherently chiral p-tert-butylcalix[4]azacrown 1 through etherification between p-tert-butylcalix[4]arene and compound 3, which can be amplified to efficiently prepare more inherently chiral calix[4]arenes in ABHH substitution pattern.
2009, 20(6): 643-644
doi: 10.1016/j.cclet.2009.02.005
Abstract:
A total synthesis of glypetelotine, the first sulphur-containing indole alkaloid from the leaf extracts of Glycosmis petelotii collected in the north of Vietnam, was described from indole through 6 steps. The structure of the glypetelotine was confirmed by IR, 1H NMR, 13C NMR and MS analysis. The spectral data of synthetic compound was identical with those of natural compound.
A total synthesis of glypetelotine, the first sulphur-containing indole alkaloid from the leaf extracts of Glycosmis petelotii collected in the north of Vietnam, was described from indole through 6 steps. The structure of the glypetelotine was confirmed by IR, 1H NMR, 13C NMR and MS analysis. The spectral data of synthetic compound was identical with those of natural compound.
2009, 20(6): 645-647
doi: 10.1016/j.cclet.2009.02.010
Abstract:
A new application of ionic liquids in the preparation of fluorescence probe 5,50'-bis-8-phenylamino-1-naphthylsulfonate (bis-ANS) is represented. The method for the preparation of fluorescence probe bis-ANS in alkyl imidazolium cationic liquids under acidic conditions is described. The effects on reaction yields under different concentration of sodium nitrite and different ionic liquid were studied and good yields were achieved.
A new application of ionic liquids in the preparation of fluorescence probe 5,50'-bis-8-phenylamino-1-naphthylsulfonate (bis-ANS) is represented. The method for the preparation of fluorescence probe bis-ANS in alkyl imidazolium cationic liquids under acidic conditions is described. The effects on reaction yields under different concentration of sodium nitrite and different ionic liquid were studied and good yields were achieved.
2009, 20(6): 648-650
doi: 10.1016/j.cclet.2008.12.048
Abstract:
Tilisolol hydrochloride 1, a non-selective β-adrenoceptor blocker, was developed as a drug for the treatment of hypertension and angina pectoris. The optical active forms of 1, 1a and 1b were synthesized from inexpensive phthalic anhydride 2 in eight steps with 13% (S) and 15% (R) overall yield.
Tilisolol hydrochloride 1, a non-selective β-adrenoceptor blocker, was developed as a drug for the treatment of hypertension and angina pectoris. The optical active forms of 1, 1a and 1b were synthesized from inexpensive phthalic anhydride 2 in eight steps with 13% (S) and 15% (R) overall yield.
2009, 20(6): 651-655
doi: 10.1016/j.cclet.2009.02.004
Abstract:
Under mild conditions, conversion of a variety of ketoximes and aldoximes to their corresponding amides and nitriles proceeded in the presence of PEG-SO3H with high yields.
Under mild conditions, conversion of a variety of ketoximes and aldoximes to their corresponding amides and nitriles proceeded in the presence of PEG-SO3H with high yields.
2009, 20(6): 656-659
doi: 10.1016/j.cclet.2008.12.050
Abstract:
The reaction of dimedone with various aromatic aldehydes produces 2,2'-arylmethylene bis (3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) in excellent yields. The reactions occur in water as solvent at room temperature and avoiding the addition of any catalyst. The workup procedure is very simple and the products do not required further purification.
The reaction of dimedone with various aromatic aldehydes produces 2,2'-arylmethylene bis (3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) in excellent yields. The reactions occur in water as solvent at room temperature and avoiding the addition of any catalyst. The workup procedure is very simple and the products do not required further purification.
2009, 20(6): 660-662
doi: 10.1016/j.cclet.2009.01.003
Abstract:
A series of novel 1,5-benzothiazepine derivatives containing COOC2H5/COONa groups at the C(2)-position were synthesized and evaluated for their antifungal and antibacterial activities by both disc diffusion and minimal inhibition concentration (MIC) methods. Most of the compounds have been shown to have moderate to good antibacterial activity against S. aureus, S. epidermidis and excellent antifungal activity against C. albicans.
A series of novel 1,5-benzothiazepine derivatives containing COOC2H5/COONa groups at the C(2)-position were synthesized and evaluated for their antifungal and antibacterial activities by both disc diffusion and minimal inhibition concentration (MIC) methods. Most of the compounds have been shown to have moderate to good antibacterial activity against S. aureus, S. epidermidis and excellent antifungal activity against C. albicans.
2009, 20(6): 663-667
doi: 10.1016/j.cclet.2008.12.045
Abstract:
The symmetric oxidative coupling reactions of 2-naphthol derivatives with both ferric hydrogensulfate in water and silica ferric hydrogensulfate in solvent free conditions were carried out. The advantages of this green procedure are:inexpensive catalyst or cocatalyst,reusability of catalyst, organic solvent-free procedures and simple workup.
The symmetric oxidative coupling reactions of 2-naphthol derivatives with both ferric hydrogensulfate in water and silica ferric hydrogensulfate in solvent free conditions were carried out. The advantages of this green procedure are:inexpensive catalyst or cocatalyst,reusability of catalyst, organic solvent-free procedures and simple workup.
2009, 20(6): 668-671
doi: 10.1016/j.cclet.2009.01.010
Abstract:
The ureido-modification of the resin-bound a luteinizing hormone releasing hormone(LHRH) analogue was investigated by CDI-activating method.The amino group at the side chain of LHRH analogue could be transformed into various substituted urea moieties in high yields. However,is its teminal amino group was partially converted to a hydantoin stucture due to the Natom of the adjacent amide bond.
The ureido-modification of the resin-bound a luteinizing hormone releasing hormone(LHRH) analogue was investigated by CDI-activating method.The amino group at the side chain of LHRH analogue could be transformed into various substituted urea moieties in high yields. However,is its teminal amino group was partially converted to a hydantoin stucture due to the Natom of the adjacent amide bond.
2009, 20(6): 672-675
doi: 10.1016/j.cclet.2009.02.007
Abstract:
A facile procedure for the synthesis of quinoxalines is being reported starting from benzil and 1,2-diaminobenzene. The reactions were carried out catalyst-free, solvent-free and under microwave irradiation conditions in high yield (84-98%) with short time (3-6 min) and environmental benign, as well as convenient operation. The structures of all the compounds have been confirmed on the basis of their IR, 1H NMR, and/or 13C NMR, mass spectral data.
A facile procedure for the synthesis of quinoxalines is being reported starting from benzil and 1,2-diaminobenzene. The reactions were carried out catalyst-free, solvent-free and under microwave irradiation conditions in high yield (84-98%) with short time (3-6 min) and environmental benign, as well as convenient operation. The structures of all the compounds have been confirmed on the basis of their IR, 1H NMR, and/or 13C NMR, mass spectral data.
2009, 20(6): 676-679
doi: 10.1016/j.cclet.2009.01.028
Abstract:
Michael addition of indole and pyrrole to a variety of α, β-unsaturated ketones was efficiently promoted by a catalytic amount of GaCl3 in aqueous media to afford the corresponding products in good to excellent yields.
Michael addition of indole and pyrrole to a variety of α, β-unsaturated ketones was efficiently promoted by a catalytic amount of GaCl3 in aqueous media to afford the corresponding products in good to excellent yields.
2009, 20(6): 680-683
doi: 10.1016/j.cclet.2009.01.023
Abstract:
Two novel steroid-linked nitrogen mustard conjugates 1a and 1b were synthesized by using estrogenic acid 4 coupled with aniline mustard 8 and phenol mustard 13 in an esterification or amidation procedure. Preliminary cytotoxic screening on cancer cell lines in vitro showed that, the steroid-ester linked nitrogen mustard conjugate 1a exhibited obvious increasing of activities.
Two novel steroid-linked nitrogen mustard conjugates 1a and 1b were synthesized by using estrogenic acid 4 coupled with aniline mustard 8 and phenol mustard 13 in an esterification or amidation procedure. Preliminary cytotoxic screening on cancer cell lines in vitro showed that, the steroid-ester linked nitrogen mustard conjugate 1a exhibited obvious increasing of activities.
2009, 20(6): 684-686
doi: 10.1016/j.cclet.2009.02.006
Abstract:
A new compound named 1-hydrate, 3-deoxy-a-D-tagatofuranose was isolated from Swertia punicea Hemsl. The structure of compound was determined by 1D and 2D NMR, HRESIMS techniques.
A new compound named 1-hydrate, 3-deoxy-a-D-tagatofuranose was isolated from Swertia punicea Hemsl. The structure of compound was determined by 1D and 2D NMR, HRESIMS techniques.
2009, 20(6): 687-689
doi: 10.1016/j.cclet.2009.01.015
Abstract:
A new panaxadiol (compound 1) was obtained from the acid hydrolysate of the total ginsenosides of Panax ginseng C. A. Meyer (Araliaceae). On the basis of spectroscopic data and single-crystal X-ray diffraction data, its chemical structure was elucidated to be dammar-(E)-20(22)-ene-3b,12β,25-triol.
A new panaxadiol (compound 1) was obtained from the acid hydrolysate of the total ginsenosides of Panax ginseng C. A. Meyer (Araliaceae). On the basis of spectroscopic data and single-crystal X-ray diffraction data, its chemical structure was elucidated to be dammar-(E)-20(22)-ene-3b,12β,25-triol.
2009, 20(6): 690-693
doi: 10.1016/j.cclet.2009.02.009
Abstract:
Two new triterpenoid saponins were isolated from the roots of Rhaponticum uniflorum. Their structures were elucidated as 3-O-[β-D-glucopyranosyl]-ilexolic acid-28-O-[β-D-glucopyranosyl] ester 1 and 3-O-[β-D-glucopyranosyl]-urs-12, 19 (29)-dien-oic acid-28-O-[β-D-glucopyranosyl] ester 2 mainly by 1D, 2D NMR techniques and chemical methods.
Two new triterpenoid saponins were isolated from the roots of Rhaponticum uniflorum. Their structures were elucidated as 3-O-[β-D-glucopyranosyl]-ilexolic acid-28-O-[β-D-glucopyranosyl] ester 1 and 3-O-[β-D-glucopyranosyl]-urs-12, 19 (29)-dien-oic acid-28-O-[β-D-glucopyranosyl] ester 2 mainly by 1D, 2D NMR techniques and chemical methods.
2009, 20(6): 694-697
doi: 10.1016/j.cclet.2008.12.037
Abstract:
A new triterpenoid saponins, raddeanoside R19 (1) was isolated from the rhizome of Anemone raddeana Regel. The effects of raddeanoside R19 on superoxide generation in human neutrophil were evaluated. The compound suppressed the superoxide generation induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP), phorbol 12-myristate 13-acetate (PMA) and arachidonic acid (AA) in a different concentration-dependent manner.
A new triterpenoid saponins, raddeanoside R19 (1) was isolated from the rhizome of Anemone raddeana Regel. The effects of raddeanoside R19 on superoxide generation in human neutrophil were evaluated. The compound suppressed the superoxide generation induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP), phorbol 12-myristate 13-acetate (PMA) and arachidonic acid (AA) in a different concentration-dependent manner.
2009, 20(6): 698-701
doi: 10.1016/j.cclet.2008.12.056
Abstract:
Three new C20-diterpenoid alkaloids, designated as anthriscifolmines A-C (1-3), together with two known alkaloids denudatine and delgramine, were isolated from the whole herb of Delphinium anthriscifolium var. savatieri. The structures of these new alkaloids were elucidated on the basis of spectral data.
Three new C20-diterpenoid alkaloids, designated as anthriscifolmines A-C (1-3), together with two known alkaloids denudatine and delgramine, were isolated from the whole herb of Delphinium anthriscifolium var. savatieri. The structures of these new alkaloids were elucidated on the basis of spectral data.
2009, 20(6): 702-705
doi: 10.1016/j.cclet.2009.02.012
Abstract:
Chemical investigation of Syringa velutinai Kom. led to the isolation of two new secoiridoid glucosides. Their structures were identified as 6'-O-(6, 7-dihyrofoliamenthoyl)-8-epi-kingisidic acid (syrveoside A, 1) and 6'-O-menthiafoloyl-8-epi-kingisidic acid (syrveoside B, 2) on the basis of chemical and physicochemical evidence.
Chemical investigation of Syringa velutinai Kom. led to the isolation of two new secoiridoid glucosides. Their structures were identified as 6'-O-(6, 7-dihyrofoliamenthoyl)-8-epi-kingisidic acid (syrveoside A, 1) and 6'-O-menthiafoloyl-8-epi-kingisidic acid (syrveoside B, 2) on the basis of chemical and physicochemical evidence.
2009, 20(6): 706-710
doi: 10.1016/j.cclet.2008.12.033
Abstract:
A new-type UV light source (206 nm) was explored for the degradation of organic pollutants in wastewater for the first time. The degradation performances of triphenyltin chloride (TPTCl), dimethyl phthalate (DMP), as well as rhodamine B (RhB) were investigated. The results indicated that removal efficiency of 50 mg/L RhB, 60 mg/L DMP and 120 mg/L TPTCl can reach 88.6%,92.5% and 89.4% for 60 min, 50 min and 75 min, respectively. By comparison of removal efficiency, we found 206 nm is superior to 253.7 nm UV in wastewater treatment, implying it is an effective, promising, and worthwhile exploring technology to decompose organic pollutants in wastewater.
A new-type UV light source (206 nm) was explored for the degradation of organic pollutants in wastewater for the first time. The degradation performances of triphenyltin chloride (TPTCl), dimethyl phthalate (DMP), as well as rhodamine B (RhB) were investigated. The results indicated that removal efficiency of 50 mg/L RhB, 60 mg/L DMP and 120 mg/L TPTCl can reach 88.6%,92.5% and 89.4% for 60 min, 50 min and 75 min, respectively. By comparison of removal efficiency, we found 206 nm is superior to 253.7 nm UV in wastewater treatment, implying it is an effective, promising, and worthwhile exploring technology to decompose organic pollutants in wastewater.
2009, 20(6): 711-715
doi: 10.1016/j.cclet.2009.02.001
Abstract:
Highly active, stable and affordable surface enhanced Raman scattering (SERS) substrates were obtained by electrolyzing a mixture of AgNO3(4×10-4 mol/L) and Na3C6H5O7·H2O (6×10-5 mol/L) for 1, 2, 3 and 4 h at 7 V.With crystal violet (CV) as a test molecule, a portable Raman spectrometer with 785 nm laser excitation was employed to carry out the SERS detection. Colloidal Ag nanoparticles prepared by electrolyzing for 3 h with the particle size of (65±17) nm is a perfect SERS substrate for the ultratrace detection of CV, which displayed an enhancement factor of ca. 1.3×108 and the detection limit of CV is down to ca.10-15 mol/L (ca. 10-4 ppb) with 10-1 mol/L KBr as aggregating agent. Thus, this SERS substrate will provide a hopeful foreground in ultratrace detection. Meanwhile, it will provide a possibility to bring Raman analysis out of the laboratory to process in situ, real-time detection and identification.
Highly active, stable and affordable surface enhanced Raman scattering (SERS) substrates were obtained by electrolyzing a mixture of AgNO3(4×10-4 mol/L) and Na3C6H5O7·H2O (6×10-5 mol/L) for 1, 2, 3 and 4 h at 7 V.With crystal violet (CV) as a test molecule, a portable Raman spectrometer with 785 nm laser excitation was employed to carry out the SERS detection. Colloidal Ag nanoparticles prepared by electrolyzing for 3 h with the particle size of (65±17) nm is a perfect SERS substrate for the ultratrace detection of CV, which displayed an enhancement factor of ca. 1.3×108 and the detection limit of CV is down to ca.10-15 mol/L (ca. 10-4 ppb) with 10-1 mol/L KBr as aggregating agent. Thus, this SERS substrate will provide a hopeful foreground in ultratrace detection. Meanwhile, it will provide a possibility to bring Raman analysis out of the laboratory to process in situ, real-time detection and identification.
2009, 20(6): 716-719
doi: 10.1016/j.cclet.2008.12.049
Abstract:
To investigate the structural form of gossypol and gossypolone Schiff's bases, seven relevant Schiff's bases were synthesized and the electrospray ionization-tandem mass spectrometry (ESI-MS/MS) with low-energy collision-induced dissociation was used to analyze their fragmentations. A common fragmentation pathway with the loss of RNH2 from those schiff's bases quasi-molecular ions was observed and proposed on the basis of their MS/MS spectra data. This common pathway indicated that those Schiff's bases existed mainly as the enamine form not the imine form previously showed in most reports.
To investigate the structural form of gossypol and gossypolone Schiff's bases, seven relevant Schiff's bases were synthesized and the electrospray ionization-tandem mass spectrometry (ESI-MS/MS) with low-energy collision-induced dissociation was used to analyze their fragmentations. A common fragmentation pathway with the loss of RNH2 from those schiff's bases quasi-molecular ions was observed and proposed on the basis of their MS/MS spectra data. This common pathway indicated that those Schiff's bases existed mainly as the enamine form not the imine form previously showed in most reports.
2009, 20(6): 720-723
doi: 10.1016/j.cclet.2009.01.018
Abstract:
Two new C-glucofuranosyl isoflavones of impurities in puerarin injection were isolated. Their structures were determined to be 8-C-α-glucofuranosyl-7, 4'-dihydroxyisoflavone and 8-C-β-glucofuranosyl-7, 4'-dihydroxy-isoflavone by chemical and spectral analysis.
Two new C-glucofuranosyl isoflavones of impurities in puerarin injection were isolated. Their structures were determined to be 8-C-α-glucofuranosyl-7, 4'-dihydroxyisoflavone and 8-C-β-glucofuranosyl-7, 4'-dihydroxy-isoflavone by chemical and spectral analysis.
2009, 20(6): 724-728
doi: 10.1016/j.cclet.2008.12.042
Abstract:
Natural phycobilisomes (PBSs) were isolated and purified from a red macroalga, Polysiphonia urceolata, by multi-step of sucrose gradient centrifugation, and were chemically stabilized by small molecule cross-linker formaldehyde. The stabilized PBSs showed similar absorption and fluorescent properties at room temperature compared to natural PBSs and kept a steady F672/F580 value during more than 3 months of storage in 0.45 mol/L phosphate buffer (pH 6.8) or at low temperature at 77 K. The stabilized PBS migrated as a single band at mild PAGE and in 14-18 h of sucrose gradient centrifugation. All these characters indicated that the stabilized PBSs were stable, soluble, homogenous fluorescent particles with favorable spectroscopic features prepared under present conditions.
Natural phycobilisomes (PBSs) were isolated and purified from a red macroalga, Polysiphonia urceolata, by multi-step of sucrose gradient centrifugation, and were chemically stabilized by small molecule cross-linker formaldehyde. The stabilized PBSs showed similar absorption and fluorescent properties at room temperature compared to natural PBSs and kept a steady F672/F580 value during more than 3 months of storage in 0.45 mol/L phosphate buffer (pH 6.8) or at low temperature at 77 K. The stabilized PBS migrated as a single band at mild PAGE and in 14-18 h of sucrose gradient centrifugation. All these characters indicated that the stabilized PBSs were stable, soluble, homogenous fluorescent particles with favorable spectroscopic features prepared under present conditions.
2009, 20(6): 729-732
doi: 10.1016/j.cclet.2008.12.047
Abstract:
Hydrosilylation has been carried out between Si-H terminated polydimethylsiloxanes with narrow molecular weight distribution and protected 3-allyloxy-1,2-propanediol, and after subsequently alcoholyzed, α-{3-[(2,3-dihydroxy)propoxy]propyl}-ω-butyl-polydimethylsiloxanes with varying number of ((Si(CH3)2-O) unit were obtained. At each step, the produced compounds were carefully characterized. The results showed that each step was successfully carried out and target products were achieved.
Hydrosilylation has been carried out between Si-H terminated polydimethylsiloxanes with narrow molecular weight distribution and protected 3-allyloxy-1,2-propanediol, and after subsequently alcoholyzed, α-{3-[(2,3-dihydroxy)propoxy]propyl}-ω-butyl-polydimethylsiloxanes with varying number of ((Si(CH3)2-O) unit were obtained. At each step, the produced compounds were carefully characterized. The results showed that each step was successfully carried out and target products were achieved.
2009, 20(6): 733-737
doi: 10.1016/j.cclet.2008.12.023
Abstract:
The reversible addition-fragmentation chain transfer (RAFT) miniemulsion polymerization of vinyl acetate (VAc) mediated by methyl (methoxycarbonothioyl) sulfanyl acetate (MMSA) was carried out. The results showed that polymerizations initiated by AIBN and KPS proceeded in a controlled way. The RAFT miniemulsion polymerization of VAc initiated by KPS showed the shorter inhibition period, higher propagation rate coefficient and final conversion than those in experiment initiated by AIBN. When the monomer conversion reached 25%, the polydispersity index (PDI) of polymer became broad, which was related to chain transfer reaction in RAFT miniemulsion of VAc.
The reversible addition-fragmentation chain transfer (RAFT) miniemulsion polymerization of vinyl acetate (VAc) mediated by methyl (methoxycarbonothioyl) sulfanyl acetate (MMSA) was carried out. The results showed that polymerizations initiated by AIBN and KPS proceeded in a controlled way. The RAFT miniemulsion polymerization of VAc initiated by KPS showed the shorter inhibition period, higher propagation rate coefficient and final conversion than those in experiment initiated by AIBN. When the monomer conversion reached 25%, the polydispersity index (PDI) of polymer became broad, which was related to chain transfer reaction in RAFT miniemulsion of VAc.
2009, 20(6): 738-742
doi: 10.1016/j.cclet.2009.02.003
Abstract:
A novel POSS-containing organic-inorganic hybrid crosslinked polymer was prepared by hydrosilylation reaction of octahydridosilsesquioxane (T8H8) with 4,4'-bis(4-allyloxybenzoyloxy)phenyl (diene A). Its structure and property was characterized by FTIR, 29Si NMR, TGA and ellipsometer, respectively. The results show that the hybrid polymer possesses high thermal stability and low dielectric constant of 1.97 at optical frequencies.
A novel POSS-containing organic-inorganic hybrid crosslinked polymer was prepared by hydrosilylation reaction of octahydridosilsesquioxane (T8H8) with 4,4'-bis(4-allyloxybenzoyloxy)phenyl (diene A). Its structure and property was characterized by FTIR, 29Si NMR, TGA and ellipsometer, respectively. The results show that the hybrid polymer possesses high thermal stability and low dielectric constant of 1.97 at optical frequencies.
2009, 20(6): 743-746
doi: 10.1016/j.cclet.2008.12.055
Abstract:
Integrating poly(lactic acid) (PLA), glycolic acid (GA) and ethylene glycol (EG) will hopefully result in a novel copolymer that combines such advantages as fastened and controllable release rate and improved flexibility together with good biocompatibility. In this study, p-dioxanone (PDO) was employed to copolymerize with DL-lactide (LA) via ring-opening melt polymerization using Sn(Oct)2 as an initiator and ethylene glycol as a co-initiator. The obtained degradable macrodiols (HO-P(LA-co-PDO)-OH) were just such a copolymer consisting of PLA, GA and EG. 1H NMR was employed to characterize the copolymers, and the effect of PDO/LA molar ratios in the feedstock on the molecular weights of HO-P(LA-co-PDO)-OH was investigated by means of endhydroxyl analysis, 1H NMR or GPC-MALLs. The results confirmed the successful synthesis of HO-P(LA-co-PDO)-OH and revealed that one end-hydroxyl of the micarodiols was donated by LA or PDO and the other one by the co-initiator EG. In addition,the molecular weights of HO-P(LA-co-PDO)-OH increased with decreasing PDO/LA ratios.
Integrating poly(lactic acid) (PLA), glycolic acid (GA) and ethylene glycol (EG) will hopefully result in a novel copolymer that combines such advantages as fastened and controllable release rate and improved flexibility together with good biocompatibility. In this study, p-dioxanone (PDO) was employed to copolymerize with DL-lactide (LA) via ring-opening melt polymerization using Sn(Oct)2 as an initiator and ethylene glycol as a co-initiator. The obtained degradable macrodiols (HO-P(LA-co-PDO)-OH) were just such a copolymer consisting of PLA, GA and EG. 1H NMR was employed to characterize the copolymers, and the effect of PDO/LA molar ratios in the feedstock on the molecular weights of HO-P(LA-co-PDO)-OH was investigated by means of endhydroxyl analysis, 1H NMR or GPC-MALLs. The results confirmed the successful synthesis of HO-P(LA-co-PDO)-OH and revealed that one end-hydroxyl of the micarodiols was donated by LA or PDO and the other one by the co-initiator EG. In addition,the molecular weights of HO-P(LA-co-PDO)-OH increased with decreasing PDO/LA ratios.
2009, 20(6): 747-750
doi: 10.1016/j.cclet.2008.12.035
Abstract:
In this article, a novel strong interaction by forming complex between bovine serum albumin (BSA) and copper ion was utilized for the preparation of molecular imprinted hydrogel in aqueous solution. Results show that the inclusion of copper ion in preparation can bridge the template BSA and functional monomers together and improve the imprinting effect compared to the polymer made without copper ion added. High selectivity factor and large adsorption capacity are also observed for the obtained BSA-imprinted hydrogel.
In this article, a novel strong interaction by forming complex between bovine serum albumin (BSA) and copper ion was utilized for the preparation of molecular imprinted hydrogel in aqueous solution. Results show that the inclusion of copper ion in preparation can bridge the template BSA and functional monomers together and improve the imprinting effect compared to the polymer made without copper ion added. High selectivity factor and large adsorption capacity are also observed for the obtained BSA-imprinted hydrogel.
2009, 20(6): 751-754
doi: 10.1016/j.cclet.2008.12.051
Abstract:
The interaction of CuCl2 to the first 16 residues of the Alzheimer's amyliod β peptide, Ab(1-16) was studied by isothermal titration calorimetry at pH 7.2 and 37℃ in aqueous solution.
The interaction of CuCl2 to the first 16 residues of the Alzheimer's amyliod β peptide, Ab(1-16) was studied by isothermal titration calorimetry at pH 7.2 and 37℃ in aqueous solution.
2009, 20(6): 755-758
doi: 10.1016/j.cclet.2009.02.002
Abstract:
Two possible reactions of NbS+ (3∑-, 1Γ) with CO in the gas phase have been studied by using B3LYP and CCSD(T) methods:the O/S exchange reaction (NbS++CO→ NbO++CS) and the S-transfer reaction (NbS++CO →Nb++COS). The two reactions have a one-step mechanism. The barriers of the O/S exchange reaction on the triplet and singlet surfaces are 51.2 and 52.4 kcal/mol,respectively, and the barriers of the S-transfer reaction are 58.3 and 78.0 kcal/mol, respectively. The results indicate that the Stransfer and the O/S exchange reaction of the 3∑- ground state of NbS+ are competing, but, for the S-transfer reaction, the 1G exited state is more reactive. The differences between the reactions of NbS+ (3∑-, 1Γ) and VS+ (3∑-, 1Γ) are discussed.
Two possible reactions of NbS+ (3∑-, 1Γ) with CO in the gas phase have been studied by using B3LYP and CCSD(T) methods:the O/S exchange reaction (NbS++CO→ NbO++CS) and the S-transfer reaction (NbS++CO →Nb++COS). The two reactions have a one-step mechanism. The barriers of the O/S exchange reaction on the triplet and singlet surfaces are 51.2 and 52.4 kcal/mol,respectively, and the barriers of the S-transfer reaction are 58.3 and 78.0 kcal/mol, respectively. The results indicate that the Stransfer and the O/S exchange reaction of the 3∑- ground state of NbS+ are competing, but, for the S-transfer reaction, the 1G exited state is more reactive. The differences between the reactions of NbS+ (3∑-, 1Γ) and VS+ (3∑-, 1Γ) are discussed.
2009, 20(6): 759-762
doi: 10.1016/j.cclet.2008.12.002
Abstract:
The interaction of nitrilotriacetic acid (NTA) and iminodiacetic acid (IDA) with tungsten(VI) (pH 7.5) and molybdenum(VI) (pH 6.00) has been studied in aqueous solutions at 25℃, and different ionic strengths (0.1 < I (mol dm-3) <1.0 for NaClO4) by a combination of potentiometric and UV spectroscopic(260-270 nm) measurements. Dependence on ionic strength was taken into account by using the Bronsted-Guggenheim-Scatchard specific ion interaction theory (SIT) and parabolic model. The data included in this work, together with some previously published data, make it possible to calculate parameters for dependence on ionic strength by using the aforementioned models.
The interaction of nitrilotriacetic acid (NTA) and iminodiacetic acid (IDA) with tungsten(VI) (pH 7.5) and molybdenum(VI) (pH 6.00) has been studied in aqueous solutions at 25℃, and different ionic strengths (0.1 < I (mol dm-3) <1.0 for NaClO4) by a combination of potentiometric and UV spectroscopic(260-270 nm) measurements. Dependence on ionic strength was taken into account by using the Bronsted-Guggenheim-Scatchard specific ion interaction theory (SIT) and parabolic model. The data included in this work, together with some previously published data, make it possible to calculate parameters for dependence on ionic strength by using the aforementioned models.
