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Showing 1 to 13 of 13 for “"benzylation"”.
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New Methods for Palladium-catalyzed Decarboxylative Benzylation, Arylation and Dearomatization Reactions
… benzyl electrophiles, catalytic decarboxylative benzylation reactions are comparatively less developed. Presented herein are the developments of new methods for the catalytic decarboxylative benzylic cross-coupling reactions with weakly-stabilized nucleophiles. In particular, the benzyl alkyne …
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Probing the mechanism of the asymmetric alkylation of pseudoephedrine amides
… · For the TBDMS derivative: 42 % for the benzylation and 17 % for the methylation · For the TIPS derivative: 34 % for the benzylation and 18 % for the methylation These results led us to think that the π-Li+ transition state is the correct one, but more experiments need to be carried out …
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Synthesis and characterization of molecules for electron transfer research.
… from 1,4-hydroquinone through bromination and benzylation. The connection of the two precursors and either permethylated silane chains or permethylated alkyl chains will give the final target molecules for ET research. Progress on this is included.
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The Anti Selective Aldol Addition of Ketones to Aldehydes Mediated by N-Amino Cyclic Carbamate Chiral Auxiliaries and Its Use in the Asymmetric Total Synthesis of (+)- and (-)-Mefloquine Hydrochloride
… conditions allows for the <italic>O</italic>-benzylation of the prepared aldol products and the subsequent removal of the ACC auxiliary to give the β-benzyloxy ketone. Both symmetric and asymmetric ketones can be utilized, and aldol products that would otherwise be difficult if not …
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Chiral phosphonyl and thiophosphonyl carbanions in asymmetric alkylation and olefination reactions
… high diastereoselectivity (90/10-97/3) and the benzylation selectivity ranged from 80/20 to 94/6. In the u-series, little steric influence on the methyl selectivity (83/17-85/15) was observed except in the case of sterically demanding group (R = $\rm C(C\sb2H\sb5)\sb3)$ where high …
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Synthesis and characterization of phosphorous containing macromolecular polyether compounds
… phospho-bipodands was performed using subsequent benzylation, phosphorylation and hydrogenation steps. The characterization of products was done using HPLC, NMR and ESI-MS techniques. The synthetic scheme used was demonstrated to be plausible and could be used to obtain ionizable phoshobipodands. …
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Selective Protein Functionalisation at Methionine
… which exhibited improved stability. Finally, a C-benzylation has been developed using photoredox catalysis to enable functionalisation of this diazo moiety. The methionine bioconjugation strategy has also been used in tandem with a literature procedure for the functionalisation of tryptophan …
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Rhizophoraceae alkaloids : an approach to the synthesis of cassipourine
… pyrrolidin-2'-yl]-propenoate followed by benzylation were unsuccessful, as were attempts to prepare the same compound by the allylic rearrangement of l-[l'-(p-toluenesulphonyl)- pyrrolidin-2'-yl]-l-hydroxyprop-2-ene. The cis-epoxide was finally successfully prepared by converting the …
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Development of an alternative synthesis of 2-acetamido-2-deoxy-L-altruronic acid: an unusual sugar found in the O-specific polysaccharide of Shigella sonnei
… in a 38% yield overall, and a further selective benzylation at O-3. Attempts to discriminate between O-2, O-3 and O-4 using low temperature acylation or alkylation conditions were unsuccessful, but modest selectivity for the 4-benzoate was observed in a Bu₂SnO-mediated benzoylation, although this …
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N9 Alkylation and Glycosylation of Purines; A Practical Synthesis of 2-Chloro-2'-deoxyadenosine
… of imidazolyl as a better leaving group via benzylation at N3 and then ammonolysis gave cladribine in good yield (79%) for 3 steps. Analogs of purine derivatives with lipophilic groups (butyl, pentyl and 2-phenylpropyl) worked almost as well.</p>
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The formation and chemistry of certain heterocyclic dianions
… equivalents of sodium amide in liquid ammonia. Benzylation of this dianion with benzyl chloride produced two diastereomers of 2,4-dibenzylglutarimide, which were separated and identified. The dianion of 3,5-morpholinedione was formed by treatment of this neutral compound with two molecular …
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Analogues of bredinin: Synthesis of 5-hydroxyimidazoles from acyclic precursors
… ester, were also unsuccessful. The unexpected benzylation of the nitrogen at position 3 of the imidazole ring, to form the quaternary ammonium salt, confirms that this is the most nucleophilic atom within the imidazole ring system.A novel linear synthetic strategy using acyclic precursors was …
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Design, Synthesis and Pharmacological Characterization of Novel Calcitonin Gene-Related Peptide Receptor Antagonists
… than the fluorosulfonyl- modified analogues. Benzylation of the His10 side-chain increased the potency of the bis-(2-chloroethyl)amino-modified irreversible antagonists but had no effect on the potency of the fluorosulfonyl-modified irreversible antagonist. The most potent analogue was …