A cleavage reaction of 1-acylhydantoin by an amine in tetrahydrofuran at elevated temperature provided the corre-sponding amide and hydantoin in high yield. It was found that the addition of diethylaluminum chloride a...A cleavage reaction of 1-acylhydantoin by an amine in tetrahydrofuran at elevated temperature provided the corre-sponding amide and hydantoin in high yield. It was found that the addition of diethylaluminum chloride accelerated the cleavage reaction rate. The amide yield depended on the steric hindrance of the amine.展开更多
Chiral 4-[(2-isopropyl-5-methylcyclohexyl)oxo]-4-oxobutanoic acid reacts with substituted anilines to produce amides 1-6 in high yields. Resulted amides 1-6 were investigated for their antifungal and antibacterial act...Chiral 4-[(2-isopropyl-5-methylcyclohexyl)oxo]-4-oxobutanoic acid reacts with substituted anilines to produce amides 1-6 in high yields. Resulted amides 1-6 were investigated for their antifungal and antibacterial activities. Compounds 2 (96.5%) against Aspergillus fumigatus and 6 (93.7%) against Helminthosporium sativum demonstrated excellent activities. However, compounds 3 (37.6%) against Bacillus subtilis, 4 (33.2%) against Pseudomonas aurignosa, 5 against Klebsiella pneumonia demonstrated excellent growth inhibition potential.展开更多
The first asymmetric hydrogenation of acyclic tetrasubstitutedα,β-unsaturated amides has been achieved by using Rh/DuanPhos complex as a catalyst,delivering chiralβ-amino amides with two contiguous chiral centers i...The first asymmetric hydrogenation of acyclic tetrasubstitutedα,β-unsaturated amides has been achieved by using Rh/DuanPhos complex as a catalyst,delivering chiralβ-amino amides with two contiguous chiral centers in excellent yields and high enantioselectivities(up to 99%yield,96%ee),which provides efficient and concise access to valuableβ-amino amide derivatives.The gram-scale reaction and efficient transformation ofβ-amino amide toβ-amino acid andβ-amino cyanide demonstrated the utility of this methodology.展开更多
Axially chiral biaryls represent the most important class of atropisomers,and they widely exist in natural products and biologically active molecules.They also constitute a unique scaffold for chiral ligands and catal...Axially chiral biaryls represent the most important class of atropisomers,and they widely exist in natural products and biologically active molecules.They also constitute a unique scaffold for chiral ligands and catalysts in organic synthesis.The development of synthetic methods to obtain such chiral compounds has received widespread attention,among which catalytically atroposelective ring-opening of configurationally labile compounds represents one of the most attractive strategies.Various substrates with strained cyclic structures,such as the renowned Bringmann's lactones,can undergo asymmetric transformation into stable atropisomers.Known advancement primarily relies on metal catalyst combined with well-designed chiral ligands,the approaches utilizing organocatalysis as a critical resolution strategy are notably scarce.In this study,we disclosed a N-heterocyclic carbene(NHC)-catalyzed asymmetric ring-opening reaction of biaryl lactams via direct atroposelective nucleophilic activation.The optimized bulky carbene catalyst ensures that the reaction can proceed under mild conditions,affording the desired product with good to excellent yields and atroposelectivity.展开更多
Eight peptoid chiral stationary phases （CSPs） terminated with N＇substituted phenyl-L-proline or L-leucine amide were prepared and evaluated under normal phase mode. With 59 racemic analytes, we compared the enantio...Eight peptoid chiral stationary phases （CSPs） terminated with N＇substituted phenyl-L-proline or L-leucine amide were prepared and evaluated under normal phase mode. With 59 racemic analytes, we compared the enantio- meric separations on CSPs terminated with p-methylphenyl, p-chlorophenyl and unsubstituted phenyl. For short peptoid selectors containing only one S-N-（1-phenylethyl） glycine （Nspe） unit, the terminal p-methyl substituent did not affect chiral recognition abilities significantly. In L-proline amide terminated CSPs, p-chloro substituent resulted in obviously inferior selectivity while in L-leucine amide terminated CSPs, it worked much better. Longer peptoid selectors containing two more Nspe units generally performed much better than the shorter ones, due to the great contributions of peptoid chain to chiral recognition. Meanwhile, the effects of the terminal substituent on selectivity were found changed on these CSPs. For CSPs terminated with L-leucine amide, the terminal p-chloro substituent in longer selector no longer produced the best recognition ability; the CSP with unsubstituted phenyl instead performed best. Comparison of these peptoid CSPs varied in terminal substituents and chain length was conducted to gain a better understanding of the chiral recognition mechanism of this type CSP and promote the development of more useful CSPs.展开更多
In connection with the current work on the synthesis of chiral insect pheromones, general methods for the preparation of chiral 2-alkylalkanoic acids were needed. Several such methods have recently been described. Mey...In connection with the current work on the synthesis of chiral insect pheromones, general methods for the preparation of chiral 2-alkylalkanoic acids were needed. Several such methods have recently been described. Meyers found that alkylation of chiral oxazoline anions followed by hydrolysis of the products gave chiral acids.展开更多
Using capillary zone electrophoresis,the enantiomers resolution of 13 pharmaceuticals including non-amide,primary amine,the secondary amine and the tertiary amine was studied with highly sulfated – α(β,γ)-cyclodex...Using capillary zone electrophoresis,the enantiomers resolution of 13 pharmaceuticals including non-amide,primary amine,the secondary amine and the tertiary amine was studied with highly sulfated – α(β,γ)-cyclodextrins(HS-α(β,γ)-CD) as chiral selector,It was found a good resolution effect for the amide chiral pharmaceuticals,especially for tertiary amine.Through the primary analysis of chiral resolution mechanism,it was believed there be the static gravitational action in addition to space matches and hydrogen bonding between highly sulfated cyclodextrins and the amine drugs.With mobility shift method,Determination of binding constants between chlorpheniramine,hydrochloride isoprenaline,naphthylethylamine and HS-β-CD showed that the binding constant order of chlorpheniramine > hydrochloride isoprenaline > naphthylethylamine,and that highly sulfonated cyclodextrins and the tertiary amine the strongest action force.展开更多
文摘A cleavage reaction of 1-acylhydantoin by an amine in tetrahydrofuran at elevated temperature provided the corre-sponding amide and hydantoin in high yield. It was found that the addition of diethylaluminum chloride accelerated the cleavage reaction rate. The amide yield depended on the steric hindrance of the amine.
文摘Chiral 4-[(2-isopropyl-5-methylcyclohexyl)oxo]-4-oxobutanoic acid reacts with substituted anilines to produce amides 1-6 in high yields. Resulted amides 1-6 were investigated for their antifungal and antibacterial activities. Compounds 2 (96.5%) against Aspergillus fumigatus and 6 (93.7%) against Helminthosporium sativum demonstrated excellent activities. However, compounds 3 (37.6%) against Bacillus subtilis, 4 (33.2%) against Pseudomonas aurignosa, 5 against Klebsiella pneumonia demonstrated excellent growth inhibition potential.
基金financial support from the National Natural Science Foundation of China(Grant Nos.22071188,22371217)Hubei Provincial Natural Science Foundation of China(2023AFA011).
文摘The first asymmetric hydrogenation of acyclic tetrasubstitutedα,β-unsaturated amides has been achieved by using Rh/DuanPhos complex as a catalyst,delivering chiralβ-amino amides with two contiguous chiral centers in excellent yields and high enantioselectivities(up to 99%yield,96%ee),which provides efficient and concise access to valuableβ-amino amide derivatives.The gram-scale reaction and efficient transformation ofβ-amino amide toβ-amino acid andβ-amino cyanide demonstrated the utility of this methodology.
基金the Natural Science Foundation of Jiangsu Province(BK20221309)the National Natural Science Foundation of China(21602105).
文摘Axially chiral biaryls represent the most important class of atropisomers,and they widely exist in natural products and biologically active molecules.They also constitute a unique scaffold for chiral ligands and catalysts in organic synthesis.The development of synthetic methods to obtain such chiral compounds has received widespread attention,among which catalytically atroposelective ring-opening of configurationally labile compounds represents one of the most attractive strategies.Various substrates with strained cyclic structures,such as the renowned Bringmann's lactones,can undergo asymmetric transformation into stable atropisomers.Known advancement primarily relies on metal catalyst combined with well-designed chiral ligands,the approaches utilizing organocatalysis as a critical resolution strategy are notably scarce.In this study,we disclosed a N-heterocyclic carbene(NHC)-catalyzed asymmetric ring-opening reaction of biaryl lactams via direct atroposelective nucleophilic activation.The optimized bulky carbene catalyst ensures that the reaction can proceed under mild conditions,affording the desired product with good to excellent yields and atroposelectivity.
文摘Eight peptoid chiral stationary phases （CSPs） terminated with N＇substituted phenyl-L-proline or L-leucine amide were prepared and evaluated under normal phase mode. With 59 racemic analytes, we compared the enantio- meric separations on CSPs terminated with p-methylphenyl, p-chlorophenyl and unsubstituted phenyl. For short peptoid selectors containing only one S-N-（1-phenylethyl） glycine （Nspe） unit, the terminal p-methyl substituent did not affect chiral recognition abilities significantly. In L-proline amide terminated CSPs, p-chloro substituent resulted in obviously inferior selectivity while in L-leucine amide terminated CSPs, it worked much better. Longer peptoid selectors containing two more Nspe units generally performed much better than the shorter ones, due to the great contributions of peptoid chain to chiral recognition. Meanwhile, the effects of the terminal substituent on selectivity were found changed on these CSPs. For CSPs terminated with L-leucine amide, the terminal p-chloro substituent in longer selector no longer produced the best recognition ability; the CSP with unsubstituted phenyl instead performed best. Comparison of these peptoid CSPs varied in terminal substituents and chain length was conducted to gain a better understanding of the chiral recognition mechanism of this type CSP and promote the development of more useful CSPs.
文摘In connection with the current work on the synthesis of chiral insect pheromones, general methods for the preparation of chiral 2-alkylalkanoic acids were needed. Several such methods have recently been described. Meyers found that alkylation of chiral oxazoline anions followed by hydrolysis of the products gave chiral acids.
文摘Using capillary zone electrophoresis,the enantiomers resolution of 13 pharmaceuticals including non-amide,primary amine,the secondary amine and the tertiary amine was studied with highly sulfated – α(β,γ)-cyclodextrins(HS-α(β,γ)-CD) as chiral selector,It was found a good resolution effect for the amide chiral pharmaceuticals,especially for tertiary amine.Through the primary analysis of chiral resolution mechanism,it was believed there be the static gravitational action in addition to space matches and hydrogen bonding between highly sulfated cyclodextrins and the amine drugs.With mobility shift method,Determination of binding constants between chlorpheniramine,hydrochloride isoprenaline,naphthylethylamine and HS-β-CD showed that the binding constant order of chlorpheniramine > hydrochloride isoprenaline > naphthylethylamine,and that highly sulfonated cyclodextrins and the tertiary amine the strongest action force.
