The Experts below are selected from a list of 3633 Experts worldwide ranked by ideXlab platform
Chaoguo Yan - One of the best experts on this subject based on the ideXlab platform.
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convenient synthesis of functionalized spiro indoline 3 2 pyrrolizines or spiro indoline 3 3 Pyrrolidines via multicomponent reactions
2015Co-Authors: Jing Sun, Hui Gong, Liang Chen, Chaoguo YanAbstract:An uncatalyzed three-component reaction of 3-methylene oxindoles, α-amino acids, and dialkyl acetylenedicarboxylates proceeds with sequential generation of active α,β-enamino ester and azomethine ylide, followed by 1,3-dipolar cycloaddition reaction.
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convenient synthesis of functionalized spiro indoline 3 2 pyrrolizines or spiro indoline 3 3 Pyrrolidines via multicomponent reactions
2015Co-Authors: Jing Sun, Hui Gong, Liang Chen, Chaoguo YanAbstract:A general and practical route for the in situ generation of a new type of azomethine ylide and its sequential 1,3-dipolar cycloaddition reaction was successfully established. The three-component reaction of secondary α-amino acids including proline, sarcosine, thiazolidine-4-carboxylic acid with dialkyl acetylenedicarboxylate and 3-methyleneoxindoles in refluxing ethanol afforded the functionalized spiro[indoline-3,2′-pyrrolizines], spiro[indoline-3,3′-Pyrrolidines] and spiro[indoline-3,6′-pyrrolo[1,2-c]thiazoles] in good yields and with high diastereoselectivity. Furthermore, similar multicomponent reactions using primary α-amino acids such as glycine, alanine and phenylalanine resulted in the corresponding (spiro[indoline-3,3′-pyrrolidine]-1′-yl)maleates.
Jing Sun - One of the best experts on this subject based on the ideXlab platform.
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convenient synthesis of functionalized spiro indoline 3 2 pyrrolizines or spiro indoline 3 3 Pyrrolidines via multicomponent reactions
2015Co-Authors: Jing Sun, Hui Gong, Liang Chen, Chaoguo YanAbstract:An uncatalyzed three-component reaction of 3-methylene oxindoles, α-amino acids, and dialkyl acetylenedicarboxylates proceeds with sequential generation of active α,β-enamino ester and azomethine ylide, followed by 1,3-dipolar cycloaddition reaction.
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convenient synthesis of functionalized spiro indoline 3 2 pyrrolizines or spiro indoline 3 3 Pyrrolidines via multicomponent reactions
2015Co-Authors: Jing Sun, Hui Gong, Liang Chen, Chaoguo YanAbstract:A general and practical route for the in situ generation of a new type of azomethine ylide and its sequential 1,3-dipolar cycloaddition reaction was successfully established. The three-component reaction of secondary α-amino acids including proline, sarcosine, thiazolidine-4-carboxylic acid with dialkyl acetylenedicarboxylate and 3-methyleneoxindoles in refluxing ethanol afforded the functionalized spiro[indoline-3,2′-pyrrolizines], spiro[indoline-3,3′-Pyrrolidines] and spiro[indoline-3,6′-pyrrolo[1,2-c]thiazoles] in good yields and with high diastereoselectivity. Furthermore, similar multicomponent reactions using primary α-amino acids such as glycine, alanine and phenylalanine resulted in the corresponding (spiro[indoline-3,3′-pyrrolidine]-1′-yl)maleates.
Ludger Witte - One of the best experts on this subject based on the ideXlab platform.
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chemotaxonomy of the pantropical genus merremia convolvulaceae based on the distribution of tropane alkaloids
2005Co-Authors: Kristina Jenettsiems, Sonja C. Ott, Karsten Siems, Robert Weigl, Anke Bohm, Petra Mann, Britta Tofernreblin, Azar Ghomian, Maki Kaloga, Ludger WitteAbstract:The occurrence and distribution of tropane and biogenetically related pyrrolidine alkaloids in 18 Merremia species of paleo-, neo-, and pantropical occurrence have been studied. The extensive GC-MS study included members of almost all sections of the genus and has been carried out with epigeal vegetative parts as well as with roots. It comprises altogether 74 tropanes and 13 Pyrrolidines including nicotine. Along with datumetine known already from a solanaceous species, the study led to the isolation (from M. dissecta and M. guerichii, respectively) and structure elucidation (spectral data) of four novel 3alpha-acyloxytropanes, merresectines A-D: 3alpha-(4-methoxybenzoyloxy)nortropane (A), 3alpha-kurameroyloxytropane (B), 3alpha-nervogenoyloxytropane (C), 3alpha-[4-(beta-D-glucopyranosyloxy)-3-methoxy-5-(3-methyl-2-butenyl)benzoyloxy]tropane (beta-d-glucoside of D). Moreover, the novel 3alpha,6beta-di-(4-methoxybenzoyloxy)tropane (merredissine) has been isolated from M. dissecta and structurally elucidated. In addition the structures of datumetine and merresectine A could be confirmed by synthesis. Spectral data for two known 3alpha-acyloxytropanes (merresectine E beta-D-glucoside, 4'-dihydroconsabatine) and one known 3beta-acyloxytropane (concneorine) are documented for the first time. The structures of three further merresectines (F-H) have been determined by mass spectrometry. Furthermore, the linkage (2',3- and 2',4-, respectively) of two position isomer N-methylpyrrolidinylhygrines was proven by synthesis. The results of the study contribute to the solution of infrageneric taxonomic problems. Whereas all species yield pyrrolidine alkaloids without suitably differentiating results the diverging occurrence of tropane alkaloids leads to three groups of sections: (1) taxa free of tropanes, (2) taxa with simple tropanes, and (3) taxa with merresectines in addition to simple tropanes.
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Chemotaxonomy of the pantropical genus Merremia (Convolvulaceae) based on the distribution of tropane alkaloids.
2005Co-Authors: Kristina Jenett-siems, Sonja C. Ott, Karsten Siems, Robert Weigl, Anke Bohm, Petra Mann, Azar Ghomian, Maki Kaloga, Britta Tofern-reblin, Ludger WitteAbstract:Abstract The occurrence and distribution of tropane and biogenetically related pyrrolidine alkaloids in 18 Merremia species of paleo-, neo-, and pantropical occurrence have been studied. The extensive GC–MS study included members of almost all sections of the genus and has been carried out with epigeal vegetative parts as well as with roots. It comprises altogether 74 tropanes and 13 Pyrrolidines including nicotine. Along with datumetine known already from a solanaceous species, the study led to the isolation (from M. dissecta and M. guerichii , respectively) and structure elucidation (spectral data) of four novel 3α-acyloxytropanes, merresectines A–D: 3α-(4-methoxybenzoyloxy)nortropane (A), 3α-kurameroyloxytropane (B), 3α-nervogenoyloxytropane (C), 3α-[4-(β- d -glucopyranosyloxy)-3-methoxy-5-(3-methyl-2-butenyl)benzoyloxy]tropane (β- d -glucoside of D). Moreover, the novel 3α,6β-di-(4-methoxybenzoyloxy)tropane (merredissine) has been isolated from M. dissecta and structurally elucidated. In addition the structures of datumetine and merresectine A could be confirmed by synthesis. Spectral data for two known 3α-acyloxytropanes (merresectine E β- d -glucoside, 4′-dihydroconsabatine) and one known 3β-acyloxytropane (concneorine) are documented for the first time. The structures of three further merresectines (F-H) have been determined by mass spectrometry. Furthermore, the linkage (2′,3- and 2′,4-, respectively) of two position isomer N -methylpyrrolidinylhygrines was proven by synthesis. The results of the study contribute to the solution of infrageneric taxonomic problems. Whereas all species yield pyrrolidine alkaloids without suitably differentiating results the diverging occurrence of tropane alkaloids leads to three groups of sections: (1) taxa free of tropanes, (2) taxa with simple tropanes, and (3) taxa with merresectines in addition to simple tropanes.
Liang Chen - One of the best experts on this subject based on the ideXlab platform.
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convenient synthesis of functionalized spiro indoline 3 2 pyrrolizines or spiro indoline 3 3 Pyrrolidines via multicomponent reactions
2015Co-Authors: Jing Sun, Hui Gong, Liang Chen, Chaoguo YanAbstract:An uncatalyzed three-component reaction of 3-methylene oxindoles, α-amino acids, and dialkyl acetylenedicarboxylates proceeds with sequential generation of active α,β-enamino ester and azomethine ylide, followed by 1,3-dipolar cycloaddition reaction.
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convenient synthesis of functionalized spiro indoline 3 2 pyrrolizines or spiro indoline 3 3 Pyrrolidines via multicomponent reactions
2015Co-Authors: Jing Sun, Hui Gong, Liang Chen, Chaoguo YanAbstract:A general and practical route for the in situ generation of a new type of azomethine ylide and its sequential 1,3-dipolar cycloaddition reaction was successfully established. The three-component reaction of secondary α-amino acids including proline, sarcosine, thiazolidine-4-carboxylic acid with dialkyl acetylenedicarboxylate and 3-methyleneoxindoles in refluxing ethanol afforded the functionalized spiro[indoline-3,2′-pyrrolizines], spiro[indoline-3,3′-Pyrrolidines] and spiro[indoline-3,6′-pyrrolo[1,2-c]thiazoles] in good yields and with high diastereoselectivity. Furthermore, similar multicomponent reactions using primary α-amino acids such as glycine, alanine and phenylalanine resulted in the corresponding (spiro[indoline-3,3′-pyrrolidine]-1′-yl)maleates.
Hui Gong - One of the best experts on this subject based on the ideXlab platform.
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convenient synthesis of functionalized spiro indoline 3 2 pyrrolizines or spiro indoline 3 3 Pyrrolidines via multicomponent reactions
2015Co-Authors: Jing Sun, Hui Gong, Liang Chen, Chaoguo YanAbstract:An uncatalyzed three-component reaction of 3-methylene oxindoles, α-amino acids, and dialkyl acetylenedicarboxylates proceeds with sequential generation of active α,β-enamino ester and azomethine ylide, followed by 1,3-dipolar cycloaddition reaction.
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convenient synthesis of functionalized spiro indoline 3 2 pyrrolizines or spiro indoline 3 3 Pyrrolidines via multicomponent reactions
2015Co-Authors: Jing Sun, Hui Gong, Liang Chen, Chaoguo YanAbstract:A general and practical route for the in situ generation of a new type of azomethine ylide and its sequential 1,3-dipolar cycloaddition reaction was successfully established. The three-component reaction of secondary α-amino acids including proline, sarcosine, thiazolidine-4-carboxylic acid with dialkyl acetylenedicarboxylate and 3-methyleneoxindoles in refluxing ethanol afforded the functionalized spiro[indoline-3,2′-pyrrolizines], spiro[indoline-3,3′-Pyrrolidines] and spiro[indoline-3,6′-pyrrolo[1,2-c]thiazoles] in good yields and with high diastereoselectivity. Furthermore, similar multicomponent reactions using primary α-amino acids such as glycine, alanine and phenylalanine resulted in the corresponding (spiro[indoline-3,3′-pyrrolidine]-1′-yl)maleates.
