| abstract |
A penam derivative of the general formulan nwherein R 1 means hydrogen, halogen, amino or protected amino; R 2 means hydrogen, halogen, lower alkoxy, lower acyl, lower alkyl, hydroxy- or protected hydroxy-substituted lower alkyl, hydroxy or protected hydroxy, or R 1 and R 2 may jointly represent oxo; R 3 means hydrogen or a carboxy-protecting group; R 4 means hydrogen; R 5 means a group of the formula -CH 2 Y where Y means halogen, -N 3 , - ON0 2 , -OR 6 , -OCOR 6 , -SCSOR 6 , -SCSN(R 6 ) 2 , -SR 6 , -S0 2 R 6 , - NHR 6 , -N(R 6 ) 2 or a substituted or unsubstituted nitrogen-containing heterocyclic group having a free valence on nitrogen; R 6 means a lower alkyl, aryl or heterocyclic group which is substituted or unsubstituted; or R 4 and R 5 may jointly represent =CH 2 ; n means 0, 1 or 2; provided, however, that where R 4 and R 5 jointly represent =CH 2 , n is not equal to 0. |