An asymmetric aza-Diels-Alder and O-Michael addition sequence has been developed to construct chiral hy- dropyrano[2,3-b]pyridine derivatives with good yields and excellent stereoselectivity, by starting with N-Ts-l-a...An asymmetric aza-Diels-Alder and O-Michael addition sequence has been developed to construct chiral hy- dropyrano[2,3-b]pyridine derivatives with good yields and excellent stereoselectivity, by starting with N-Ts-l-aza- 1,3-butadienes and aliphatic aldehydes tethered to an α,β-unsaturated ketone motif. A tandem O-Michael addition reaction was completed via acid catalysis.展开更多
The one-pot aza-Diels-Alder reaction of substituted aromatic amines, ethyl glyoxylate and benzyl vinylcarbamate or N- benzyloxycarbonyl 2-pyrroline was conducted in hexafluoroisopropanol, providing the desired 1,2,3,4...The one-pot aza-Diels-Alder reaction of substituted aromatic amines, ethyl glyoxylate and benzyl vinylcarbamate or N- benzyloxycarbonyl 2-pyrroline was conducted in hexafluoroisopropanol, providing the desired 1,2,3,4-tetrahydroquinline derivatives in moderate yields.展开更多
Different novel fused multicyclic iminosugars were synthesized from D-ribose tosylate,aniline and vinyl ethyl ether by one-pot three-component stereoselective[4+2]reaction at different temperatures.The iminium-ion is ...Different novel fused multicyclic iminosugars were synthesized from D-ribose tosylate,aniline and vinyl ethyl ether by one-pot three-component stereoselective[4+2]reaction at different temperatures.The iminium-ion is the key intermediate for the reaction.As a result,several complex fused iminosugars 3a were obtained by aza-Diels-Alder mechanism at 60℃,while a series of aza-C-glycosides 5a were prepared by Mannich reaction at room temperature accompanied by another tetrahydroquinoline-fused iminosugars 4a(tricyclic derivatives)through aza-Diels-Alder cycloaddition.This strategy will help to construct structurally diverse and bioactive iminosugar analogues.展开更多
Efficient nitrosonium （NO＋）-initiated aza-Diels-Alder reactions of N-arylimines with 2,3-dihydrofuran or 3,4-dihydro-2H-pyran allowed access to furano[3,2-c]- or pyrano[3,2-c]quinolines. A mixture of cis and trans-...Efficient nitrosonium （NO＋）-initiated aza-Diels-Alder reactions of N-arylimines with 2,3-dihydrofuran or 3,4-dihydro-2H-pyran allowed access to furano[3,2-c]- or pyrano[3,2-c]quinolines. A mixture of cis and trans-quinoline isomers was obtained in various ratios and yields.展开更多
A series of substituted 2,3-diaryl-2-azabicyclo[2.2.2]octan-5-ones have been prepared by an efficient three-component aza-Diels-Alder cycloaddition reaction in water catalyzed by layered α-zirconium hydrogen phospha...A series of substituted 2,3-diaryl-2-azabicyclo[2.2.2]octan-5-ones have been prepared by an efficient three-component aza-Diels-Alder cycloaddition reaction in water catalyzed by layered α-zirconium hydrogen phosphate （α-ZrP） and sodium calix[4]arene sulfonates bearing pendant short aliphatic chains. The 18 synthesized compounds were assayed for acetylcholinesterase inhibition using mouse acetvlcho]inesterase.展开更多
The direct three-component aza-Diels–Alder reaction was conducted with lipase as a catalyst for the first time. Under the optimized conditions, the aza-Diels–Alder reaction catalyzed by lipase from Candida sp.99–12...The direct three-component aza-Diels–Alder reaction was conducted with lipase as a catalyst for the first time. Under the optimized conditions, the aza-Diels–Alder reaction catalyzed by lipase from Candida sp.99–125 provided the products in moderate to excellent yields. Meanwhile, the endo/exo ratio reached up to 88：12.展开更多
An efficient approach has been developed for the synthesis of 5,5＇-diaryl-2,2＇-bipyridines via their 1,2,4-triazine analogues.The notable advantages of the present method are：The possibility of varying the aromatic...An efficient approach has been developed for the synthesis of 5,5＇-diaryl-2,2＇-bipyridines via their 1,2,4-triazine analogues.The notable advantages of the present method are：The possibility of varying the aromatic substituents in the positions 5 and 5＇ of bipyridine core and the possibility for obtaining 2,2＇-bipyridines bearing a fused cyclopentene core to increase the solubility in organic solvents.These 5,5＇-diaryl-2,2＇-bipyridines exhibited an intense emission in a range of ca.422-521 nm in acetonitrile solution;depending on the nature of the aromatic substituents and the presence of annulated cyclopentene fragments.Apart from that,the significant bathochromic shifts of the both absorption and emission maxima were observed in comparison with a number of previously described similar structures.In some cases the significant increasing of the fluorescence quantum yields took place.展开更多
文摘An asymmetric aza-Diels-Alder and O-Michael addition sequence has been developed to construct chiral hy- dropyrano[2,3-b]pyridine derivatives with good yields and excellent stereoselectivity, by starting with N-Ts-l-aza- 1,3-butadienes and aliphatic aldehydes tethered to an α,β-unsaturated ketone motif. A tandem O-Michael addition reaction was completed via acid catalysis.
基金the National Natural Science Foundation of China(No.30672540)NSF of Beijing(No.7072048)for financial support.
文摘The one-pot aza-Diels-Alder reaction of substituted aromatic amines, ethyl glyoxylate and benzyl vinylcarbamate or N- benzyloxycarbonyl 2-pyrroline was conducted in hexafluoroisopropanol, providing the desired 1,2,3,4-tetrahydroquinline derivatives in moderate yields.
基金supported by the National Natural Science Foundation of China(NSFC)(21772031)the Natural Science Foundations of Hebei Province(B2019201398).
文摘Different novel fused multicyclic iminosugars were synthesized from D-ribose tosylate,aniline and vinyl ethyl ether by one-pot three-component stereoselective[4+2]reaction at different temperatures.The iminium-ion is the key intermediate for the reaction.As a result,several complex fused iminosugars 3a were obtained by aza-Diels-Alder mechanism at 60℃,while a series of aza-C-glycosides 5a were prepared by Mannich reaction at room temperature accompanied by another tetrahydroquinoline-fused iminosugars 4a(tricyclic derivatives)through aza-Diels-Alder cycloaddition.This strategy will help to construct structurally diverse and bioactive iminosugar analogues.
基金Project supported by the National Natural Science Foundation of China （No. 20572040）.
文摘Efficient nitrosonium （NO＋）-initiated aza-Diels-Alder reactions of N-arylimines with 2,3-dihydrofuran or 3,4-dihydro-2H-pyran allowed access to furano[3,2-c]- or pyrano[3,2-c]quinolines. A mixture of cis and trans-quinoline isomers was obtained in various ratios and yields.
基金financial support from the Natural Science Foundation of China(No.21176222)
文摘A series of substituted 2,3-diaryl-2-azabicyclo[2.2.2]octan-5-ones have been prepared by an efficient three-component aza-Diels-Alder cycloaddition reaction in water catalyzed by layered α-zirconium hydrogen phosphate （α-ZrP） and sodium calix[4]arene sulfonates bearing pendant short aliphatic chains. The 18 synthesized compounds were assayed for acetylcholinesterase inhibition using mouse acetvlcho]inesterase.
基金supported in part by the Natural Science Foundation of Jiangsu Province (No. BK2012763)the Fundamental Research Funds of the Central Universities from the Ministries of Education and Finance of China (No. ZD2014YX0027)
文摘The direct three-component aza-Diels–Alder reaction was conducted with lipase as a catalyst for the first time. Under the optimized conditions, the aza-Diels–Alder reaction catalyzed by lipase from Candida sp.99–125 provided the products in moderate to excellent yields. Meanwhile, the endo/exo ratio reached up to 88：12.
基金supported by the Russian Science Foundation(No.15-13-10033)
文摘An efficient approach has been developed for the synthesis of 5,5＇-diaryl-2,2＇-bipyridines via their 1,2,4-triazine analogues.The notable advantages of the present method are：The possibility of varying the aromatic substituents in the positions 5 and 5＇ of bipyridine core and the possibility for obtaining 2,2＇-bipyridines bearing a fused cyclopentene core to increase the solubility in organic solvents.These 5,5＇-diaryl-2,2＇-bipyridines exhibited an intense emission in a range of ca.422-521 nm in acetonitrile solution;depending on the nature of the aromatic substituents and the presence of annulated cyclopentene fragments.Apart from that,the significant bathochromic shifts of the both absorption and emission maxima were observed in comparison with a number of previously described similar structures.In some cases the significant increasing of the fluorescence quantum yields took place.
