Synthesis and structure-activity relationships of novel lincomycin derivatives. Part 1. Newly generated antibacterial activities against Gram-positive bacteria with erm gene by C-7 modification

We synthesized 7(S)-7-deoxy-7-arylthiolincomycin derivatives possessing a heterocyclic ring at the C-7 position via sulfur atom by either Mitsunobu reaction of 2,3,4-tris-O-(trimethylsiliyl)lincomycin or S(N)2 reaction of 7-O-methanesulfonyl-2,3,4-tri-O-trimethylsiliyllincomycin. As a result, 7(S)-7-deoxy-7-arylthiolincomycin derivatives 16, 21 and 27 exhibited antibacterial activities against respiratory infection-related Gram-positive bacteria with erm gene, although clindamycin did not have any activities against those pathogens. Furthermore, 7(S)-configuration of lincomycin derivatives was found to be necessary for enhancing antibacterial activities from the comparison results of configurations of 16 (S-configuration) and 30 (R-configuration) at the 7-position.