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Biomedical subjects

Timothy B Durham

Publications and source records attributed to Timothy B Durham.

7 recordsLinked to original sources
PubMed2006

Progress toward the discovery and development of efficacious BACE inhibitors.

BACE (beta-site amyloid precursor protein [APP] cleavage enzyme) is a transmembrane aspartyl protease responsible for the first cleavage event in the processing of APP to Abeta peptide. Amyloid plaques composed of Abeta peptides are hypothesized to be the root cause of neuronal cell death in Alzheimer's disease patients. Thus, BACE has become a target of significant interest for pharmaceutical and academic research. The recent literature relating to the discovery and development of efficacious BACE inhibitors is reviewed with particular emphasis on the patent literature.

Alzheimer Disease↗
PubMed2004

Total synthesis of formamicin.

The enantioselective total synthesis of the cytotoxic plecomacrolide natural product formamicin (1) is described. Key aspects of this synthesis include the efficient transacetalation reactions of MOM ethers 28 and 38 to form the seven-membered formyl acetals 29 and 39, a late-stage Suzuki cross-coupling reaction of the highly functionalized vinyl boronic acid 6 and vinyl iodide 7, a highly beta-selective glycosidation reaction of beta-hydroxy ketone 4 with 2,6-dideoxy-2-iodoglucopyranosyl fluoride 3, and the global desilylation of penultimate intermediate 77 mediated by in situ generated Et(3)N.2HF.

Glycosylation↗
PubMed2003

Enantioselective synthesis of alpha-amino acids from N-tosyloxy beta-lactams derived from beta-keto esters.

A novel synthetic sequence has been developed to convert simple beta-keto esters into enantiomerically enriched alpha-amino acids. The key features of this sequence include the addition of azide to the C3 position of beta-keto ester derived N-tosyloxy-beta-lactams through a concomitant nucleophilic addition/N-O bond reduction reaction, a mild CsF-induced N1 benzylation of alpha-azido monocyclic beta-lactams, the preparation of alpha-keto-beta-lactams through a novel four-step sequence from the corresponding 3-azido-1-benzyl-beta-lactams, and TEMPO-mediated ring expansion of these compounds to the corresponding N-carboxy anhydrides (NCAs). In addition, the synthesis, isolation, and characterization of unusual 3-imino and 3-chloramino-beta-lactams is reported.

Amino Acids↗
PubMed2003

An enantioselective synthesis of differentially protected erythro-alpha,beta-diamino acids and its application to the synthesis of an analogue of rhodopeptin B5.

Methodology for the enantioselective synthesis of differentially protected erythro-alpha,beta-diamino acids from N-tosyloxy beta-lactams is reported. The requisite N-tosyloxy beta-lactams are readily available from simple beta-keto esters. The reported approach is flexible and compatible with a variety of functional groups. The synthetic utility of the method is demonstrated through its application to the preparation of an analogue of the antifungal cyclic peptide rhodopeptin B5.

Amino Acids↗
PubMed2002

Conversion of glucuronic acid glycosides to novel bicyclic beta-lactams.

[reaction: see text] Methodology for the conversion of glucuronic acid glycosides to novel bicyclic beta-lactams is reported. Using this strategy, we prepared two novel templates suitable for use in combinatorial chemistry strategies for the construction of a number of interesting beta-lactam motifs. Key features of this strategy include a diastereoselective Ferrier reaction of a glucuronic acid glucal, selective beta-lactam ring formation using a cyclic allylic alcohol, and a chemoselective benzylic oxidation.

Combinatorial Chemistry Techniques↗