The penems, a new class of .beta.-lactam antibiotics. 2. Total synthesis of racemic 6-unsubstituted representatives

My 50-Plus Years of Academic Research Collaborations with Industry. A Retrospective

A retrospective is presented highlighting the synthesis of selected "first-in-kind" natural products, their synthetic analogues, structure elucidations, and rationally designed bioactive synthetic compounds that were accomplished because of collaborations with past and present pharmaceutical and agrochemical companies. Medicinal chemistry projects involving structure-based design exploiting cocrystal structures of small molecules with biologically relevant enzymes, receptors, and bacterial ribosomes with synthetic small molecules leading to marketed products, clinical candidates, and novel drug prototypes were realized in collaboration. Personal reflections, historical insights, behind the scenes stories from various long-term projects are shared in this retrospective article.

The Chemical Relationship Among Beta-Lactam Antibiotics and Potential Impacts on Reactivity and Decomposition

Beta-lactam antibiotics remain one of the most commonly prescribed drug classes, but they are limited by their propensity to cause hypersensitivity reactions (e.g., from allergy to anaphylaxis) as well as by the emergence of bacteria with a myriad of resistance mechanisms such as β-lactamases. While development efforts continue to focus on overcoming resistance, there are ongoing concerns regarding cross-contamination of β-lactams during manufacturing and compounding of these drugs. Additionally, there is a need to reduce levels of drugs such as β-lactam antibiotics in waste-water to mitigate the risk of environmental exposure. To help address future development of effective remediation chemistries and processes, it is desired to better understand the structural relationship among the most common β-lactams. This study includes the creation of a class-wide structural ordering of the entire β-lactam series, including both United States Food and Drug Association (US-FDA)-approved drugs and experimental therapies. The result is a structural relational map: the “Lactamome,” which positions each substance according to architecture and chemical end-group. We utilized a novel method to compare the structural relationships of β-lactam antibiotics among the radial cladogram and describe the positioning with respect to efficacy, resistance to hydrolysis, reported hypersensitivity, and Woodward height. The resulting classification scheme may help with the development of broad-spectrum treatments that reduce the risk of occupational exposure and negative environmental impacts, assist practitioners with avoiding adverse patient reactions, and help direct future drug research.

Phosphorus-containing amino acids with a P–C bond in the side chain or a P–O, P–S or P–N bond: from synthesis to applications

Strategies for the preparation of phosphorus-containing amino acids and their utility in the organic chemistry, physico-chemistry, agrochemistry, and pharmacology fields are reported.

[New orally active penem antibiotic: Farom]

An orally active penem antibiotic, Farom (generic name: faropenem), was designed by the conformational analysis of active and inactive penem derivatives. Faropenem showed potent activity against a wide variety of bacteria including extended-spectrum beta-lactamase (ESBL)-producing ones. The mechanism of the stability against ESBL was elucidated by modeling the Michaelis complex of faropenem and Toho-1, an ESBL. Modeling of a complex of faropenem at the active site of a penicillin-binding protein 2 (PBP2) model suggested the characteristic affinity for faropenem with PBP2 of Escherichia coli. Faropenem has been totally synthesized from (R)-1,3-butanediol. The synthetic intermediate, a 3-hydroxyethyl-4-acetoxyazetidinone derivative, was efficiently prepared by the 2 + 2 coupling of a optically active vinylsulfide derivative and chlorosulfonyl isocyanate, followed by the substitution of the acetoxy group for the thiophenyl group at the C-4 position.