(+)‐(5 R ,6 S )‐2‐(1′‐Aminoalkyl)‐6‐(hydroxyalkyl)penem‐3‐carboxylic Acids

In continuation of our work on penem antibiotics, novel chiral (5 R ,6 S )‐2‐(1′‐aminoalkyl)‐6‐(hydroxyalkyl)‐derivatives 1 have been synthesized by two essentially different strategies. Whereas the starting materials for 1a ‐ f , azetidinones 2 and 5 , were obtained from chiral building blocks (6‐aminopenicillanic acid and L‐threonine, resp.), the one for 1g , azetidinone 9 , was derived from racemic 4‐acetoxyazetidinone and, as chiral auxiliary, (2 R )‐2‐mercaptopropan‐1‐ol. The 2‐aminomethyl derivatives 1a (CGP 30 779) and 1f (CGP 31 608) proved the most potent compounds in the antibacterial tests in vitro and showed a well‐balanced spectrum of activity by comparison with that of established β‐lactams.