[Structure-activity relationship of cephalosporins. II. Effect of oxygen-containing functional groups on the biological activity od cephalosporins--derivatives of 7-aminocephalosporanic acid]. / Sviaz' struktura-aktivnost' tsefalosporinovykh antibiotikov. II. Vliianie kislorodsoderzhashchikh funktsional'nykh grupp na aktivnost' tsefalosporinov--proizvodnykh 7-aminotsefalosporanovoi kisloty.

The statistical analysis of 529 compounds belonging to the group of cephalosporins revealed a significant influence of oxygen-containing descriptors of the radical at position 7 in the cefem nucleus on the biological activity of the compounds. It was concluded that prediction of the antimicrobial properties of the antibiotics by the pattern recognition was possible with using factors reflecting the presence and space arrangement of the following functional groups in the cephalosporin molecules:-OH (phenolic group), C-O-C (ether), C = O (ester, amide) and -O- (in the heterocycle). The results of the study were compared with the data on the impact of nitrogen-containing descriptors on the biological activity of cephalosporins and practical recommendations for synthesis of new active compounds were proposed.

[Structure-activity relationship of cephalosporins. III. Effect of sulfur-containing functional groups on the biological activity of cephalosporins--derivatives of 7-aminocephalosporanic acid]. / Sviaz' struktura-aktivnost' tsefalosporinovykh antibiotikov. III. Vliianie serosoderzhashchikh funktsional'nykh grupp na aktivnost' tsefalosporinov-proizvodnykh 7-aminotsefalosporanovoi kisloty.

The relationship between the in vitro antimicrobial activity of cephalosporin antibiotics and the presence and space arrangement of sulfur-containing descriptors of the radical at position 7 in the cefem nucleus was studied. It was noted that the sulfur-containing fragments were markedly less frequent in the structures of the known cephalosporins than the nitrogen- and oxygen-containing descriptors. It was concluded that at present information related only to two of the fragments under investigation might be used as characteristics in predicting antimicrobial activity of cephalosporins by the pattern recognition. On the basis of the studies there were defined two principle paths for synthesis of new antibiotics: introduction into the molecule structure of the functional groups providing with high probability improvement of the antimicrobial properties and preparation of compounds containing descriptors whose impact on the biological activity is not known.