Nine racemic homocamptothecin derivatives were synthesized and in vitro antitumor activities were evaluated by standard MTT method. The results showed that some of the compound had higher antitumor activity than irite...Nine racemic homocamptothecin derivatives were synthesized and in vitro antitumor activities were evaluated by standard MTT method. The results showed that some of the compound had higher antitumor activity than iritecan.展开更多
Poly[(alanino ethyl ester)0.67 (glycino ethyl ester)0.33 phosphazene] (PAGP) was synthesized, and morphology and diameter of the electrospun PAGP nanofibers were systematically evaluated by using a cool field em...Poly[(alanino ethyl ester)0.67 (glycino ethyl ester)0.33 phosphazene] (PAGP) was synthesized, and morphology and diameter of the electrospun PAGP nanofibers were systematically evaluated by using a cool field emission scanning electron microscope (SEM) with changing the important processing variables such as applied voltage, polymeric concentration, and ambient temperature. The average diameter of PAGP nanofibers was inversely proportional to the applied voltage, but increased with the increase of solution concentration. Lower environmental temperature was unfavorable due to the nanofibers conglutination.展开更多
With the aid of a Pyrolysis-GC/TOF MS technique, the pyrolysis behaviour of two menthyl esters of N-benzoxycarbonyl amino acid was investigated. A clear pattern emerges involving the cleavage of the bond linking the m...With the aid of a Pyrolysis-GC/TOF MS technique, the pyrolysis behaviour of two menthyl esters of N-benzoxycarbonyl amino acid was investigated. A clear pattern emerges involving the cleavage of the bond linking the menthyl ring to the carboxy group, followed by further degradation of the fragments. The major pyroproducts were p-menth-l-ene pyrolysed at a higher temperature or p-menth-2-ene pyrolysed at a lower temperature, and various derivatives of cyclohexene pyrolyzed from the menthyl ring. In addition, some of the products were also iden- tified as derivatives of benzene from the pyrolysis of benzyloxyl moiety.展开更多
A rosmarinic acid derivative, tetramethyl ether of rosmarinic acid benzyl ester, was synthesized. This is the first report of building this structural skeleton.
A salvianolic acid A derivative, hexamethyl ether of salvianolic acid A benzyl ester, was synthesized in fourteen steps. The overall yield was 3.4 parts per thousand. The compound was identified by (1)HNMR and MS. Thi...A salvianolic acid A derivative, hexamethyl ether of salvianolic acid A benzyl ester, was synthesized in fourteen steps. The overall yield was 3.4 parts per thousand. The compound was identified by (1)HNMR and MS. This is the first report of building this structural skeleton.展开更多
The binding mode of the amino acid ethyl esters(guest) by 5 (2 carboxylphenyl) 10,15,20 triphenylporphyrinatozinc(Ⅱ)(host 1) was studied by means of 1H NMR spectra. The binding mode is the hydrogen bonding between th...The binding mode of the amino acid ethyl esters(guest) by 5 (2 carboxylphenyl) 10,15,20 triphenylporphyrinatozinc(Ⅱ)(host 1) was studied by means of 1H NMR spectra. The binding mode is the hydrogen bonding between the amino group of the guest and the carboxyl group of host 1 plus the coordination between the zinc atom of porphyrinatozinc(Ⅱ) and the carbonyl group of the guest. This is a novel binding mode of the metalloporphyrin to amino acid derivatives.展开更多
Amino acid methyl ester phosphates were synthesized and determined by using positive-ion mode dectrospmy ionization mass spectrometry(ESIMS) in combination with multistage tandem mass spectrometry. The fragmentation...Amino acid methyl ester phosphates were synthesized and determined by using positive-ion mode dectrospmy ionization mass spectrometry(ESIMS) in combination with multistage tandem mass spectrometry. The fragmentation pathways were investigated, and it was observed that most fragment ions contained the phosphoryl group. It was interesting to observe that the fragmentation pathways of the protonated molecule show some differences when compared with those of the sodium ion adduct. The methoxy group of amino acid methyl ester can migrate from the carbonyl group to the phosphoryl group in the sodium ion adduct.展开更多
A series of novel phosphonoacetic acid derivatives, N-(ethoxycarbonylmethy-ethoxyphosphonyl)-α-amino acid esters and α-amino phosphonates, were synthesized via the reaction of the corresponding phosphonyl chloride ...A series of novel phosphonoacetic acid derivatives, N-(ethoxycarbonylmethy-ethoxyphosphonyl)-α-amino acid esters and α-amino phosphonates, were synthesized via the reaction of the corresponding phosphonyl chloride with amino acid ester hydrochlorides or amino phosphonates in the presence of a base. The preliminary bioassay shows that some compounds show significant anti-viral activity against tobacco mosaic virus (TMV)展开更多
We herein report our studies into the effects of microwave irradiation on the solvent-free esterification of L-leucine with alcohols. In the absence of solvent, microwave irradiation accelerated the reaction compared ...We herein report our studies into the effects of microwave irradiation on the solvent-free esterification of L-leucine with alcohols. In the absence of solvent, microwave irradiation accelerated the reaction compared to conventional oil bath heating. Measurement of the dielectric properties under the reaction conditions revealed that the high dielectric loss factor of the reaction mixture containing L-leucine, n-butanol, and a p-toluene sulfonic acid catalyst could be attributed to the acceleration of the reaction. The depth of microwave penetration into the reaction mixture as derived from the in-situ measurement of the dielectric properties was ~13 mm, which suggested that a thinner reaction vessel was favorable for the esterification of L-leucine. In addition to the batch reaction using a desktop microwave reactor, two types of flow reaction were also performed using a desktop tubular reactor and a semi-bench-scale tubular reactor. These flow reactions also exhibited high performances, thus allowing the scale-up of this reaction system for industrial use.展开更多
The reductive alkylation of amine with carbonyl compounds using sodium hydrogen telluride has been investigated in recent years. Application of this method to the synthesis of N-alkyl derivatives of biologically impor...The reductive alkylation of amine with carbonyl compounds using sodium hydrogen telluride has been investigated in recent years. Application of this method to the synthesis of N-alkyl derivatives of biologically important amino acids and their esters is described.展开更多
Four kinds of new macrocycles containing amino acids and nyl-heterocyclic units were synthesized by the condensation of di-esters containing Ts-amino acids units with di-halogenated compounds at room temperature. The ...Four kinds of new macrocycles containing amino acids and nyl-heterocyclic units were synthesized by the condensation of di-esters containing Ts-amino acids units with di-halogenated compounds at room temperature. The macrocycles were characterized by elemental analysis, IR,MS(FAB) and 1H NMR展开更多
Enantiomerically pure a-substituted bamino esters were prepared from natural L-a-amino acids through Arndt-Eistert homologation and diastereoselective aalkylation.
Lipophilic complexes of macrocyclic 12-membered dioxotetraamine ligand bearing bis-hydroxy groups as functional pendants are effective catalysts for the hydrolysis of amino acid esters in micellar media, and the rate ...Lipophilic complexes of macrocyclic 12-membered dioxotetraamine ligand bearing bis-hydroxy groups as functional pendants are effective catalysts for the hydrolysis of amino acid esters in micellar media, and the rate enhancement of more than 10-fold were observed.展开更多
Several cyclic amino acids (1-4) were synthesized from glycine. Isocyanate ester was prepared as the key intermediate and reacted with dibromoalkanes to afford the target compounds.
A series of novel N-[α-(isoflavone-7-O-)acetyl] amino acid methyl esters were prepared from the efficient and regioselective alkylation of isoflavones with chloroacetyl amino acid derivatives under mild condition.
The review provides an overview of the approaches, applications, and methods for ester prodrugs. Ester prodrugs are pharmacologically inactive compounds in their original form but become active drugs on biotransformat...The review provides an overview of the approaches, applications, and methods for ester prodrugs. Ester prodrugs are pharmacologically inactive compounds in their original form but become active drugs on biotransformation within the body, which offers advantages concerning the solubility, stability, and targeted delivery of the active drug. Several approaches of ester prodrugs have been reviewed in this review, including simple ester prodrugs, amino acid ester prodrugs, sugar ester prodrugs, lipid ester prodrugs, and polymeric ester prodrugs. This review incorporates in vitro and in vivo methods as well as the characterization of physical and chemical properties for ester prodrugs, cell culture systems, enzymatic assays, and animal models—all of these having a very important bearing on the evaluation of stability, bioavailability, and efficacy for ester prodrugs. While the benefits of using ester prodrugs are significant, there are also disadvantages like instability, poor or variable enzymatic hydrolysis, and toxicity from released promoieties or by-products. This review discusses solutions to the various limitations that include enhancing stability with ionizable promoieties and using physiologically-based pharmacokinetic modeling. The review also highlights the application of ester prodrugs in neurological disorders, such as Parkinson’s disease, and the ongoing efforts to address the critical limitations in treatment efficacy. Future prodrug strategies are poised to advance significantly by harnessing diverse transport mechanisms across the blood-brain barrier and integrating nanotechnology.展开更多
β-Amino esters were synthesized via ZnCl2-catalyzed Mannich-type reaction of imines and malonate esters under solvent-free conditions in 6 min. The β-amino ester was converted into the corresponding aspartic acid de...β-Amino esters were synthesized via ZnCl2-catalyzed Mannich-type reaction of imines and malonate esters under solvent-free conditions in 6 min. The β-amino ester was converted into the corresponding aspartic acid derivatives.展开更多
基金the National Natural Science Foundation of China (No.30371689)Shanghai Major Program Science and Technology Foundation (No.064319009)Shanghai Leading Academic Discipline Project (No.B906).
文摘Nine racemic homocamptothecin derivatives were synthesized and in vitro antitumor activities were evaluated by standard MTT method. The results showed that some of the compound had higher antitumor activity than iritecan.
基金Funded by the National Natural Science Foundation of China (No.50873012)
文摘Poly[(alanino ethyl ester)0.67 (glycino ethyl ester)0.33 phosphazene] (PAGP) was synthesized, and morphology and diameter of the electrospun PAGP nanofibers were systematically evaluated by using a cool field emission scanning electron microscope (SEM) with changing the important processing variables such as applied voltage, polymeric concentration, and ambient temperature. The average diameter of PAGP nanofibers was inversely proportional to the applied voltage, but increased with the increase of solution concentration. Lower environmental temperature was unfavorable due to the nanofibers conglutination.
基金Supported by the Key Project on Anhui Province Natural Science Study by Colleges and Universities(No.KJ2008A094)
文摘With the aid of a Pyrolysis-GC/TOF MS technique, the pyrolysis behaviour of two menthyl esters of N-benzoxycarbonyl amino acid was investigated. A clear pattern emerges involving the cleavage of the bond linking the menthyl ring to the carboxy group, followed by further degradation of the fragments. The major pyroproducts were p-menth-l-ene pyrolysed at a higher temperature or p-menth-2-ene pyrolysed at a lower temperature, and various derivatives of cyclohexene pyrolyzed from the menthyl ring. In addition, some of the products were also iden- tified as derivatives of benzene from the pyrolysis of benzyloxyl moiety.
文摘A rosmarinic acid derivative, tetramethyl ether of rosmarinic acid benzyl ester, was synthesized. This is the first report of building this structural skeleton.
文摘A salvianolic acid A derivative, hexamethyl ether of salvianolic acid A benzyl ester, was synthesized in fourteen steps. The overall yield was 3.4 parts per thousand. The compound was identified by (1)HNMR and MS. This is the first report of building this structural skeleton.
文摘The binding mode of the amino acid ethyl esters(guest) by 5 (2 carboxylphenyl) 10,15,20 triphenylporphyrinatozinc(Ⅱ)(host 1) was studied by means of 1H NMR spectra. The binding mode is the hydrogen bonding between the amino group of the guest and the carboxyl group of host 1 plus the coordination between the zinc atom of porphyrinatozinc(Ⅱ) and the carbonyl group of the guest. This is a novel binding mode of the metalloporphyrin to amino acid derivatives.
基金Supported by the National Natural Science Foundation of China(No.20572061).
文摘Amino acid methyl ester phosphates were synthesized and determined by using positive-ion mode dectrospmy ionization mass spectrometry(ESIMS) in combination with multistage tandem mass spectrometry. The fragmentation pathways were investigated, and it was observed that most fragment ions contained the phosphoryl group. It was interesting to observe that the fragmentation pathways of the protonated molecule show some differences when compared with those of the sodium ion adduct. The methoxy group of amino acid methyl ester can migrate from the carbonyl group to the phosphoryl group in the sodium ion adduct.
文摘A series of novel phosphonoacetic acid derivatives, N-(ethoxycarbonylmethy-ethoxyphosphonyl)-α-amino acid esters and α-amino phosphonates, were synthesized via the reaction of the corresponding phosphonyl chloride with amino acid ester hydrochlorides or amino phosphonates in the presence of a base. The preliminary bioassay shows that some compounds show significant anti-viral activity against tobacco mosaic virus (TMV)
文摘We herein report our studies into the effects of microwave irradiation on the solvent-free esterification of L-leucine with alcohols. In the absence of solvent, microwave irradiation accelerated the reaction compared to conventional oil bath heating. Measurement of the dielectric properties under the reaction conditions revealed that the high dielectric loss factor of the reaction mixture containing L-leucine, n-butanol, and a p-toluene sulfonic acid catalyst could be attributed to the acceleration of the reaction. The depth of microwave penetration into the reaction mixture as derived from the in-situ measurement of the dielectric properties was ~13 mm, which suggested that a thinner reaction vessel was favorable for the esterification of L-leucine. In addition to the batch reaction using a desktop microwave reactor, two types of flow reaction were also performed using a desktop tubular reactor and a semi-bench-scale tubular reactor. These flow reactions also exhibited high performances, thus allowing the scale-up of this reaction system for industrial use.
文摘The reductive alkylation of amine with carbonyl compounds using sodium hydrogen telluride has been investigated in recent years. Application of this method to the synthesis of N-alkyl derivatives of biologically important amino acids and their esters is described.
文摘Four kinds of new macrocycles containing amino acids and nyl-heterocyclic units were synthesized by the condensation of di-esters containing Ts-amino acids units with di-halogenated compounds at room temperature. The macrocycles were characterized by elemental analysis, IR,MS(FAB) and 1H NMR
基金The project is generously supported by the National Natural Science Foundation of China (Grant No. 29972002 20172002)+1 种基金 the Trans-Century Training Programme Foundation for the Talents by Ministry of Education and Bayer Co. Ltd (Germany). We thank Dr
文摘Enantiomerically pure a-substituted bamino esters were prepared from natural L-a-amino acids through Arndt-Eistert homologation and diastereoselective aalkylation.
文摘Lipophilic complexes of macrocyclic 12-membered dioxotetraamine ligand bearing bis-hydroxy groups as functional pendants are effective catalysts for the hydrolysis of amino acid esters in micellar media, and the rate enhancement of more than 10-fold were observed.
基金the National Natural Science Foundation of China(No.20272001)
文摘Several cyclic amino acids (1-4) were synthesized from glycine. Isocyanate ester was prepared as the key intermediate and reacted with dibromoalkanes to afford the target compounds.
文摘A series of novel N-[α-(isoflavone-7-O-)acetyl] amino acid methyl esters were prepared from the efficient and regioselective alkylation of isoflavones with chloroacetyl amino acid derivatives under mild condition.
文摘The review provides an overview of the approaches, applications, and methods for ester prodrugs. Ester prodrugs are pharmacologically inactive compounds in their original form but become active drugs on biotransformation within the body, which offers advantages concerning the solubility, stability, and targeted delivery of the active drug. Several approaches of ester prodrugs have been reviewed in this review, including simple ester prodrugs, amino acid ester prodrugs, sugar ester prodrugs, lipid ester prodrugs, and polymeric ester prodrugs. This review incorporates in vitro and in vivo methods as well as the characterization of physical and chemical properties for ester prodrugs, cell culture systems, enzymatic assays, and animal models—all of these having a very important bearing on the evaluation of stability, bioavailability, and efficacy for ester prodrugs. While the benefits of using ester prodrugs are significant, there are also disadvantages like instability, poor or variable enzymatic hydrolysis, and toxicity from released promoieties or by-products. This review discusses solutions to the various limitations that include enhancing stability with ionizable promoieties and using physiologically-based pharmacokinetic modeling. The review also highlights the application of ester prodrugs in neurological disorders, such as Parkinson’s disease, and the ongoing efforts to address the critical limitations in treatment efficacy. Future prodrug strategies are poised to advance significantly by harnessing diverse transport mechanisms across the blood-brain barrier and integrating nanotechnology.
基金the financial support form National Natural Science Foundation of China(No.20472116).
文摘β-Amino esters were synthesized via ZnCl2-catalyzed Mannich-type reaction of imines and malonate esters under solvent-free conditions in 6 min. The β-amino ester was converted into the corresponding aspartic acid derivatives.