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Showing 1 to 20 of 23 for “"Pictet–Spengler"”.
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Synthetic Studies in the Formation of Nitrogen Containing Compounds: From Simple Amines to Complex Natural Products
… synthesis of (±)-Lundurine A via vinylogous Pictet-Spengler reaction and our progress toward the catalytic asymmetric vinylogous Pictet-Spengler reaction. The Lundurines are an interesting class of indole containing alkaloids that have shown biological activity. Although there are completed …
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Crystallization studies of Pictet-Spenglerases
… the first committed reaction. This reaction is a Pictet-Spengler coupling between tryptamine and secologanin and produces the biosynthetic intermediate strictosidine, common to all monoterpene indole alkaloids. To better understand the structural features that impart binding selectivity, …
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A Drug Discovery Study: Inhibitor Design for HRV 3C Protease Based on the Scaffold of (-)-Thysanone
… approach for 7-deoxy analogues using an oxa-Pictet-Spengler reaction in the key step. This oxa-Pictet-Spengler approach was also used for development of a new synthetic strategy for thysanone also involving C-H activation chemistry.
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Discovery, characterization, and rational design of the enzymes involved in monoterpene indole alkaloid biosynthesis in Madagascar periwinkle
… is strictosidine, the product of an asymmetric Pictet- Spengler condensation of tryptamine and the iridoid monoterpene secologanin. This reaction is catalyzed by the enzyme strictosidine synthase. This thesis describes the use of kinetic isotope effects, the rate dependence on pH, as well as …
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Untersuchungen zur endogenen Bildung, Cytotoxizität und DNA-schädigenden Wirkung des dopaminergen Neurotoxins TaClo
… Aufnahme des Schlafmittels Chloralhydrat durch Pictet-Spengler-Kondensation mit dem endogen vorhandenen Tryptamin gebildet wird. Zusätzlich scheint die Bildung von TaClo aus dem Industrielösungsmittel TRI (Trichlorethylen), das im Organismus zu Chloral metabolisiert wird, möglich. Die über …
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The Application of the Titanium-Catalyzed Hydroamination of Alkynes toward the Synthesis of Benzylisoquinoline Derivatives
… formation of the berberin-bridge using a Pictet-Spengler reaction afforded (–)-(S)-xylopinine (102). The strategy was also applied to synthesize benzylisoquinolines with electron-deficient A-rings. 5-Trifluoromethyl-benzylisoquinoline (174) was successfully synthesized in 8 steps from …
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Synthetic studies of ecteinascidin 743 and fennebricin B
… of the natural product in 2008, featuring the Pictet-Spengler reaction to construct the pentacyclic core of Et-743. Our work, however, also produced both desired and undesired pentacycle without selectivity. We herein described an improved formal synthesis of Et-743 employing bromine auxiliary …
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Synthesis of the Antimalarial Flindersial Alkaloids
… and 3-butyn-2-one undergo a vinylogous Pictet-Spengler reaction to give a β-carboline, which opens to a 2-enone tryptamine in the presence of base. A BINOL catalyzed enantioselective conjugate addition of a vinyl boronic acid to the 2-enone tryptamine has been achieved. A …
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Exploiting alkaloid biosynthesis in Madagascar periwinkle to obtain natural product derivatives and new biocatalysts
… a biocatalyst, since it catalyzes the asymmetric Pictet- Spengler reaction to form tetrahydro-p-carboline pharmacophores. I used computer modeling to propose a model for how strictosidine synthase achieves its high stereoselectivity; this model may be used to engineer a Pictet-Spenglerase that …
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Human alkaloid biosynthesis : chemical inducers of Parkinson's disease?
… evaluate enzyme activity were modeled after the Pictet-Spengler condensation catalyzed by the plant enzyme. Substrates were selected based on their potential to form alkaloids previously identified in central nervous system tissue. Product formation was monitored via high-performance liquid …
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Carbon-nitrogen bond-forming reactions in supercritical and expanded-liquid carbon dioxide media : green synthetic chemistry with multiscale reaction and phase behavior modeling
… dioxide and a dialkyl carbonate and (2) the Pictet-Spengler cyclization of these carbamates by their reaction with an aldehyde in the presence of acid. The conversion of amines to their carbamate derivatives offered suitable N-protection against carbamic acid formation.
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Asymmetric Catalysis with Brønsted Acids: Experiments and Calculations
… in this work include imino-Diels-Alder and Pictet-Spengler reactions. Moreover, a S,O-thioacetalization reaction to furnish 1,3-oxathiolanes enantioselectively is presented. In the latter project, after thorough and systematic screenings, it was noteworthy that the catalyst loading of …
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Chemical studies of metabolites from Pacific Ocean marine sponges and the starfish Dermasterias imbricata
… imbricatine (3) was accomplished using a Pictet-Spengler reaction to couple the starting materials 3-(3,5-dihydroxyphenyl) alanine methyl ester (143) and sodium 3-(4-benzyloxyphenyl) glycidate (141). A series of deprotections and protections on the resulting racemic …
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Upgrading alcohols with bio-oxidation and chemo-catalysis in single-flask processes
… been interfaced with same-flask KPi-catalyzed Pictet-Spengler annulation. This methodology accommodates two different biocatalysts, C2-C5 linear and branched alcohols, and both m-tyramines and tryptamines to to deliver near-quantitative conversion to tetrahydroisoquioline and tryptoline …
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Development and characterization of anti-EGFR protein-drug conjugates for tumor therapy
… motifs. The biocompatible hydrazine-_iso_-Pictet-Spengler (HIPS) and tandem Knoevenagel ligations allowed for the bioconjugation of aldehyde moieties on the surface of live cells, which were introduced by sodium periodate oxidation. However, labeling of _in situ_ formed FGly in transiently …
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Proteinkonjugationen durch Kupfer-abhängige Formylglycin-generierende Enzyme zur Generierung von Antikörper-Wirkstoff-Konjugaten
… aldehyde-specific HIPS ligation (Hydrazino-iso-Pictet-Spengler) and then loaded with a toxin by click reaction. The consecutive use of enzymes with different substrate specificity enables bioorthogonality of the conjugation, whereby for the first time dual ADCs were generated using FGly …
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Harnessing Deep Learning with Protein Language Models to Unveil Microbial Enzyme Function in Health and Disease
… I identified a remote homolog of McbB, a Pictet-Spengler enzyme, using structural search. McbB is hypothesised to synthesise ligands for GPR35, a receptor genetically linked to IBD. These discoveries, facilitated by deep learning tools, could offer new insights into IBD pathology and lead …
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Antimalarial Agents: New Mechanisms of Actions for Old and New Drugs
… A-, B-, C- and D-ring. In the process, a novel Pictet-Spengler ring expansion reaction of ortho-substituted acetphenones was discovered. The ring-expanded products were identified by means of 1D and 2D NMR experiments, HRMS, and X-ray crystallography. Among the 73 analogs prepared, four …
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Hit to Lead Stage Optimization of Orally Efficacious β-Carboline Antimalarials
… of compound TCMDC-140230 was accomplished via Pictet-Spengler reaction of (S)- and (R)-7-methyl tryptophan methyl ester and 3,4-dichlorobenzaldehyde. The individual stereoisomeric esters were converted to the corresponding amides, but none of the stereoisomers of TCMDC-140230 were potent …
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Novel Antimalarial Compounds from the Optimization of the Malaria Box
Malaria continues to threaten human beings, causing a staggering number of more than 400,000 deaths each year. Although effective treatment and prevention methods are available, rapidly emerging resistance towards existing drugs is of great concern, and the need for novel antimalarial compounds are …
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