| abstract |
The invention relates to novel peptides and their pharmaceutically acceptable salts, particularly useful for pharmaceutical purposes such as in the therapeutic treatment of infectious diseases caused by pathogenic microorganisms. The compounds have the structure <IMAGE> wherein R1 is hydrogen or acyl; R2 is carboxy or protected carboxy or a group of the formula: -COHN-Ra2 wherein Ra2 is carboxy (lower) alkyl or protected carboxy (lower) alkyl; R3 is carboxy, protected carboxy, lower alkyl, hydroxyphenyl, carbamoyl or a group of the formula: <IMAGE> wherein Ra3 is hydrogen, amino, protected amino or acylamino, Rb3 is carboxy or protected carboxy; Rp is carboxy, protected carboxy, carbamoyl, carboxy (lower) alkyl or protected carboxy (lower) alkyl; l is an integer 2, m is an integer 0 to 2 and n is an integer 1, provided that, when R1 is hydrogen or acyl, R2 is carboxy, protected carboxy or a group of the formula: -CONHRa2 wherein Ra2 is carboxy (lower) alkyl or protected carboxy (lower) alkyl, Rp is carboxy, or protected carboxy, m is an integer 2, then R3 is carbamoyl, lower alkyl or hydroxyphenyl or a group of the formula: <IMAGE> wherein Ra3 is hydrogen or acylamino and Rb3 is carboxy or protected caboxy, and when Rp is carbamoyl, then R1 is acyl. |