Heterogeneous Catalysts in Pictet-Spengler-Type Reactions
نویسندگان
چکیده
منابع مشابه
Thiourea-catalyzed enantioselective iso-Pictet-Spengler reactions.
A one-pot condensation of isotryptamines and aldehydes that affords enantiomerically enriched 4-substituted tetrahydro-γ-carbolines is reported. The reaction is induced by a chiral thiourea/benzoic acid dual catalyst system. Purification of the N-Boc-protected products by trituration or crystallization provides the optically pure tetrahydro-γ-carboline derivatives in a scalable and highly pract...
متن کاملWeak Brønsted acid-thiourea co-catalysis: enantioselective, catalytic protio-Pictet-Spengler reactions.
The development of one-pot imine formation and asymmetric Pictet-Spengler reactions cocatalyzed by a chiral thiourea and benzoic acid is described. Optically active tetrahydro-beta-carbolines, ubiquitous structural motifs in biologically active natural products, are obtained in high ee directly from tryptamine and aldehyde precursors.
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The use of bifunctional catalysts in organic synthesis finds inspiration in the selectivity of enzymatic catalysis which arises from the specific interactions between basic and acidic amino acid residues and the substrate itself in order to stabilize developing charges in the transition state. Many enzymes act as bifunctional catalysts using amino acid residues at the active site as Lewis acids...
متن کاملA Pictet-Spengler ligation for protein chemical modification.
Aldehyde- and ketone-functionalized proteins are appealing substrates for the development of chemically modified biotherapeutics and protein-based materials. Their reactive carbonyl groups are typically conjugated with α-effect nucleophiles, such as substituted hydrazines and alkoxyamines, to generate hydrazones and oximes, respectively. However, the resulting C=N linkages are susceptible to hy...
متن کاملMild and efficient cyanuric chloride catalyzed Pictet–Spengler reaction
A practical, mild and efficient protocol for the Pictet-Spengler reaction catalyzed by cyanuric chloride (trichloro-1,3,5-triazine, TCT) is described. The 6-endo cyclization of tryptophan/tryptamine and modified Pictet-Spengler substrates with both electron-withdrawing and electron-donating aldehydes was carried out by using a catalytic amount of TCT (10 mol %) in DMSO under a nitrogen atmosphe...
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ژورنال
عنوان ژورنال: Journal of Chemistry
سال: 2013
ISSN: 2090-9063,2090-9071
DOI: 10.1155/2013/125302