The synthesis and antibacterial activity of the tide compounds are described. Both 2-hydroxymethyl and 2-hydroxypropcnyl carbapenems (3 and 14) served as the common key intermediates for the preparation of these compounds. The characteristic antibacterial activity was observed in the three types (A, B, and C) of derivatives prepared. Although many modification studies on carbapenem antibiotics have been reported, chemical manipulation has been limited to the alkylthio or naturally occurring cysteamino group at the C-2 position. Our interest in this area was to maximize the activity displayed from hybridization of the carbapenem nucleus and cephalosporin C-3 side chains.l.2Recently we repotted that 1 fi-methylcarbapenems having quaternary heteroaromatic-thiomethyl groups at the C-2 position exemplified by compound 1 exhibited broad and well-balanced antibacterial activity, except against Pseudomonas aeruginosa.3 This tinding led us to inquire whether the interposition of different spacers between the carbapenem nucleus and the quatemary nitrogen would influence their antibacterial properties. Here we report the synthesis and antibacterial activity of a new class of carbapenems represented by types A, B, and C.