Process for preparing 6- and 2-substituted-1-carbadethiapen-2-em-3-carboxylic acids

Abstract

Abstract A process is disclosed for preparing antibiotic 6- and 2-substituted-1-carbadethiapen-2-em-3-carboxylic acids and their pharmaceutically acceptable salts and esters (I) ##STR1## wherein: R 1 and R 2 are selected from hydrogen, alkyl aryl, and aralkyl; and R 3 is hydrogen, --R, --OR, or --SR, wherein R is hydrogen, alkyl, aryl or aralkyl. The process comprises complexing an appropriately substituted δ,ω-unsaturated amino acid with a transition metal carbonyl complex, followed by oxidatively induced ligand transfer and ring closure: ##STR2## wherein: F p =η 5 --C 5 H 5 Fe(CO) 2 and F p (isobutene.sup.⊕ represents a cationic complex between F p and an olefin such as isobutene, which complex cation is employed in the initial ligand exchange reaction; R 4 is lower alkyl or phenyl; R 5 is a readily removable blocking group or pharmaceutically acceptable ester radical; and R 1 , R 2 and R 3 are as defined above.

Inventors

• 👤 David H. Shih

Bibliographic Details