Jordan Hirshfield

Synthetic carbapenem antibiotics II. Stereoisomers of 7-hydroxyethyl-2,2,5-trimethyl-3-oxa-1-azabicyclo[4.2.O]octan-8-one

Abstract The titled compounds are key synthetic intermediates in the structure-activity relationship studies of novel 1-methyl carbapenem antibiotics. Preparation and structural determination of these stereoisomers by x-ray crystallography and proton NMR spectroscopy are reported.

Inhibition of procine kidney “enkephalinase” by substituted-N-carboxymethyl dipeptides

Abstract A design effective for generating inhibitors of angiotensin converting enzyme has been successfully extended to inhibitors of another Zn ++ peptidase. A series of potent inhibitors for the zinc metalloendopeptidase associated with porcine kidney microsomes has been developed. Most contain the (S)-N-(1-carboxy-3-phenylpropyl)-L-Phe-X backbone. The most effective inhibitors with ID 50 values in the 10 −7 M range at pH 7.5 and 22°C were those where X = glycine, β-alanine, γ-amino butyric acid. A simple nomenclature designating substituted N-carboxy-methyl amino acid derivatives as -[N]- sharing amino acid derivatives is described.

Stereoselective synthesis of the dihydrobenzo[b]furan segments of the ephedradine alkaloids

Syntheses of dihydrobenzofuran derivatives have involved formation of phenol substituted β-hydroxy esters by an aldol reaction followed by Lewis-acid-catalysed intramolecular cyclisation as key steps; the use of chiral oxazolidinones in the aldol reaction has formed the basis of enantionspecific syntheses.