PENEM DERIVATIVES

The invention relates to 2-penem-3-carboxylic acid compounds of the formula (I) in which Ra represents an organic radical bonded by a carbon atom to the ring carbon atom, a free, etherified or esterified hydroxy or mercapto group or a halogen atom, R1 represents hydrogen, an organic radical bonded by a carbon atom to the ring carbon atom, or an etherified mercapto group, and R2 represents a hydroxy group or an R2A radical that together with the carbonyl grouping -C(=O)- forms a protected carboxyl group, and to salts of such compounds with salt-forming groups, processes for the manufacture of such compounds, pharmaceutical preparations containing compounds of the formula I with pharmacological properties, and their use. The compounds have antibiotic activity.