In order to probe the effect of C-2(S)-substituted groups in the antibacterial activity,a series of novel C-2(S)-substituted pleuromutilin analogues of SB-225586 were synthesized and evaluated for their in vitro antib...In order to probe the effect of C-2(S)-substituted groups in the antibacterial activity,a series of novel C-2(S)-substituted pleuromutilin analogues of SB-225586 were synthesized and evaluated for their in vitro antibacterial activity.The results of antibacterial activities indicated that C-2(S)-substituted pleuromutilin derivatives retained appreciable antibacterial activity,and the 2-fluorination compounds 6a and 6b are more potent than the corresponding 2-hydroxylation analogues 7a and 7b.展开更多
Four novel 5-substituted pyridine-2(1H)-one derivatives were designed and synthesized by using addition-elimination reactions.The structures of these novelly synthesized compounds were verified by ~1H NMR,ESI-MS and s...Four novel 5-substituted pyridine-2(1H)-one derivatives were designed and synthesized by using addition-elimination reactions.The structures of these novelly synthesized compounds were verified by ~1H NMR,ESI-MS and single crystal X-ray diffraction.Furthermore,all four compounds(most notably compound 7a) were found to be highly efficient against hepatitis B virus (HBV) in cultured HepG2 2.2.15 cell,making them promising drug candidates for potential bioactive molecule against hepatitis B.展开更多
A convenient method to synthesize substituted 2 (2' hydroxyphenyl) benzimidazoles is reported. Six title compounds have been synthesized by the reaction of salicylic acid and 4 substituted o phenylene...A convenient method to synthesize substituted 2 (2' hydroxyphenyl) benzimidazoles is reported. Six title compounds have been synthesized by the reaction of salicylic acid and 4 substituted o phenylenediamine in the presence pyridine POCl 3 . Three compounds were tested as plant virucide against tobacco mosaic virus and they exhibited some activities.展开更多
The polyacetylated(4,6-dimethylpyrimidin-2-yl)1-thioglycopyrano- sides(-)were obtained in high yields with stereoselectivity by phase-transfer catalyzed synthesis,and their structures were confirmed by elemental analy...The polyacetylated(4,6-dimethylpyrimidin-2-yl)1-thioglycopyrano- sides(-)were obtained in high yields with stereoselectivity by phase-transfer catalyzed synthesis,and their structures were confirmed by elemental analysis and IR,~1H-NMR spectral data.展开更多
A series of novel 2-（1-substituted-1,11-undecylidene）-5-arylimino-△^3-1,3,4-thiadiazolines （4） were synthesized and their structure was characterized by ^1H NMR, ^13C NMR and elemental analysis. Their solubility ...A series of novel 2-（1-substituted-1,11-undecylidene）-5-arylimino-△^3-1,3,4-thiadiazolines （4） were synthesized and their structure was characterized by ^1H NMR, ^13C NMR and elemental analysis. Their solubility in both polar and non-polar solvents is significantly improved owing to the introduction of ethyl or methylthio group at cyclododecyl ring as compared with parent compounds [1, 2-（1,11-undecylidene）-5-arylimino-△^3-1,3,4-thiadiazolines]. However, their fungicidal activity against Rhizoctonia solani is less than that of parent compounds. X-ray diffraction analysis of a representative compound （4d） showed that the conformation of 12-membered ring is still [3333], in which the ethyl group present at the side-exo position and the thiadiazoline ring at the comer carbon. The thiadiazoline plane is perpendicular to the cyclododecyl one.展开更多
Proceeding from natural amino acid L-asparagine and commercially available aldehydes a stereoselective synthesis was developed of (2S,4S)-2-alkyl(aryl)-3-(3-sulfanylpropanoyl)-6-oxohexahy- dropyrimidine-4-carboxylic a...Proceeding from natural amino acid L-asparagine and commercially available aldehydes a stereoselective synthesis was developed of (2S,4S)-2-alkyl(aryl)-3-(3-sulfanylpropanoyl)-6-oxohexahy- dropyrimidine-4-carboxylic acids, potential antihypertensive drugs, inhibitors of the angiotensin converting enzyme.展开更多
Simple and efficient stereo-selective synthesis of exo-5-norbornene-2-carboxylic acid (NBCA) is reported. Preliminary studies on base promoted isomerization of methyl 5-norbornene-2-carboxylate (MNBC) revealed that ra...Simple and efficient stereo-selective synthesis of exo-5-norbornene-2-carboxylic acid (NBCA) is reported. Preliminary studies on base promoted isomerization of methyl 5-norbornene-2-carboxylate (MNBC) revealed that rapid isomerization was accomplished with sodium tert-butoxide (tBuONa), and the exo-content at the equilibrium was ca. 60%. The hydrolyses of endo-rich MNBC (endo/exo = 80/20) under various conditions were carried out. The exo selectivity for resulting NBCA was improved when the hydrolysis was conducted with equimolar water at room temperature in the presence of the stronger base (tBuONa) (endo/exo: 18/82). Whereas the use of excess amount of water led to rapid and non-selective hydrolysis affording high endo content of the product. The plausible reaction mechanism involving rapid equilibrium of thermodynamic isomerization and kinetically preferred hydrolysis of exo ester is proposed.展开更多
Sixteen title compounds were synthesized, twelve of which are new ones. Their structures were determined by 1H NMR, IR and MS, the refractive indices or melting points were measured. Odors of all the title compounds w...Sixteen title compounds were synthesized, twelve of which are new ones. Their structures were determined by 1H NMR, IR and MS, the refractive indices or melting points were measured. Odors of all the title compounds were evaluated and the structure-odor relationship was briefly discussed.展开更多
A cleaner and eco-friendly method was developed for the preparation of tetrakis(aminomethyl)calix-[4]-resorcinarene via a synthetic pathway of five steps starting from methylresorcinol. This alternative methodology is...A cleaner and eco-friendly method was developed for the preparation of tetrakis(aminomethyl)calix-[4]-resorcinarene via a synthetic pathway of five steps starting from methylresorcinol. This alternative methodology is firstly based on avoiding the use of CH2BrCl, which is a non-eco-friendly substance with high ozone depletion potential, and on replacing it by CH2Cl2 as a readily available reagent with much less dangerous effects. Secondly, this method engages acetone or CH2Cl2 as the solvent of the bromination step in the place of the very toxic CCl4, leading to tetrakis(bromomethyl)calix-[4]-resorcinarene. The brominated intermediate has been reacted with sodium azide in acetone instead of the high-boiling solvent DMSO to produce tetrakis(azidomethyl) calix-[4]-resorcinarene without the need of tedious purification. Lastly, this work reports an efficient hydrogenation method of the versatile azido adduct employing Pt/C (5%) as the catalyst for the preparation of the amino cavitand as an alternative route with high atom economy that can replace the classical methods used currently.展开更多
A novel and efficient approach to the synthesis of 2-substituted benzimidazoles has been developed via CuI/DMEDA-catalyzed coupling reaction and post-cyclization with glacial acetic acid from readily available 2-iodoa...A novel and efficient approach to the synthesis of 2-substituted benzimidazoles has been developed via CuI/DMEDA-catalyzed coupling reaction and post-cyclization with glacial acetic acid from readily available 2-iodoanilines and amides. This method is suitable for the construction of a variety of benzimidazoles in moderate to good yields under short reaction times.展开更多
文摘In order to probe the effect of C-2(S)-substituted groups in the antibacterial activity,a series of novel C-2(S)-substituted pleuromutilin analogues of SB-225586 were synthesized and evaluated for their in vitro antibacterial activity.The results of antibacterial activities indicated that C-2(S)-substituted pleuromutilin derivatives retained appreciable antibacterial activity,and the 2-fluorination compounds 6a and 6b are more potent than the corresponding 2-hydroxylation analogues 7a and 7b.
文摘Four novel 5-substituted pyridine-2(1H)-one derivatives were designed and synthesized by using addition-elimination reactions.The structures of these novelly synthesized compounds were verified by ~1H NMR,ESI-MS and single crystal X-ray diffraction.Furthermore,all four compounds(most notably compound 7a) were found to be highly efficient against hepatitis B virus (HBV) in cultured HepG2 2.2.15 cell,making them promising drug candidates for potential bioactive molecule against hepatitis B.
文摘A convenient method to synthesize substituted 2 (2' hydroxyphenyl) benzimidazoles is reported. Six title compounds have been synthesized by the reaction of salicylic acid and 4 substituted o phenylenediamine in the presence pyridine POCl 3 . Three compounds were tested as plant virucide against tobacco mosaic virus and they exhibited some activities.
文摘The polyacetylated(4,6-dimethylpyrimidin-2-yl)1-thioglycopyrano- sides(-)were obtained in high yields with stereoselectivity by phase-transfer catalyzed synthesis,and their structures were confirmed by elemental analysis and IR,~1H-NMR spectral data.
基金supports from the National Basic Research Program of China(No. 2003CB 114407)
文摘A series of novel 2-（1-substituted-1,11-undecylidene）-5-arylimino-△^3-1,3,4-thiadiazolines （4） were synthesized and their structure was characterized by ^1H NMR, ^13C NMR and elemental analysis. Their solubility in both polar and non-polar solvents is significantly improved owing to the introduction of ethyl or methylthio group at cyclododecyl ring as compared with parent compounds [1, 2-（1,11-undecylidene）-5-arylimino-△^3-1,3,4-thiadiazolines]. However, their fungicidal activity against Rhizoctonia solani is less than that of parent compounds. X-ray diffraction analysis of a representative compound （4d） showed that the conformation of 12-membered ring is still [3333], in which the ethyl group present at the side-exo position and the thiadiazoline ring at the comer carbon. The thiadiazoline plane is perpendicular to the cyclododecyl one.
文摘Proceeding from natural amino acid L-asparagine and commercially available aldehydes a stereoselective synthesis was developed of (2S,4S)-2-alkyl(aryl)-3-(3-sulfanylpropanoyl)-6-oxohexahy- dropyrimidine-4-carboxylic acids, potential antihypertensive drugs, inhibitors of the angiotensin converting enzyme.
文摘Simple and efficient stereo-selective synthesis of exo-5-norbornene-2-carboxylic acid (NBCA) is reported. Preliminary studies on base promoted isomerization of methyl 5-norbornene-2-carboxylate (MNBC) revealed that rapid isomerization was accomplished with sodium tert-butoxide (tBuONa), and the exo-content at the equilibrium was ca. 60%. The hydrolyses of endo-rich MNBC (endo/exo = 80/20) under various conditions were carried out. The exo selectivity for resulting NBCA was improved when the hydrolysis was conducted with equimolar water at room temperature in the presence of the stronger base (tBuONa) (endo/exo: 18/82). Whereas the use of excess amount of water led to rapid and non-selective hydrolysis affording high endo content of the product. The plausible reaction mechanism involving rapid equilibrium of thermodynamic isomerization and kinetically preferred hydrolysis of exo ester is proposed.
基金Supported hy the National Natural Science Foundation of China
文摘Sixteen title compounds were synthesized, twelve of which are new ones. Their structures were determined by 1H NMR, IR and MS, the refractive indices or melting points were measured. Odors of all the title compounds were evaluated and the structure-odor relationship was briefly discussed.
文摘A cleaner and eco-friendly method was developed for the preparation of tetrakis(aminomethyl)calix-[4]-resorcinarene via a synthetic pathway of five steps starting from methylresorcinol. This alternative methodology is firstly based on avoiding the use of CH2BrCl, which is a non-eco-friendly substance with high ozone depletion potential, and on replacing it by CH2Cl2 as a readily available reagent with much less dangerous effects. Secondly, this method engages acetone or CH2Cl2 as the solvent of the bromination step in the place of the very toxic CCl4, leading to tetrakis(bromomethyl)calix-[4]-resorcinarene. The brominated intermediate has been reacted with sodium azide in acetone instead of the high-boiling solvent DMSO to produce tetrakis(azidomethyl) calix-[4]-resorcinarene without the need of tedious purification. Lastly, this work reports an efficient hydrogenation method of the versatile azido adduct employing Pt/C (5%) as the catalyst for the preparation of the amino cavitand as an alternative route with high atom economy that can replace the classical methods used currently.
基金Acknowledgement We are grateful for support of this project by the National Natural Science Foundation of China （No. J1103307） and the project of Science Foundation of Gansu Province （No. 1208RJZA266）.
文摘A novel and efficient approach to the synthesis of 2-substituted benzimidazoles has been developed via CuI/DMEDA-catalyzed coupling reaction and post-cyclization with glacial acetic acid from readily available 2-iodoanilines and amides. This method is suitable for the construction of a variety of benzimidazoles in moderate to good yields under short reaction times.
