The Synthesis & Optimizium Of Biapenem Side Chain

Biapenem 1,6-[[(4R,5S,6S)-2-carboxy-6-[(1R)-1-hydroxyethyl]-4-methyl-7-oxo -1-azabicyclo[3.2.0]hept-2-en-3-yl]thio]-6,70dihydro-5H-pyrazolo[1,2-a][1,2,4]triazo 1-4-ium hydroxide,inner salt,is a new non-natural 1β-methylcarbapenem antibiotic which exhibits a wide range of antibacterial activity,remarkable chemical stability, and extensive stability against human renal dehydropeptidase-Ⅰ(DHP-Ⅰ).Biapenem 1 bearing a bicyclotriazolium thio group at C2 as the pendant moiety is strikingly different from that of the other 1β-methylcarbapenems. Mercaptobicyclotriazolium chloride 3 useful for the pendant moiety of 1 was successfully synthesized starting from hydrazine hydrate along an economically availably synthetic route in 22%yield.