Studies on 6 alpha-substituted penicillins. II. Synthesis and structure-activity relationships of 6 beta-(2-aryl-2-sulfoacetamido)-6 alpha-methoxy penicillanic acids.

The synthesis and antibacterial activity of 6 alpha-methoxysulbenicillin analogues (2) are described. Structure-activity studies of these derivatives bearing hydrophilic substituents in the phenyl ring led to the identification of disodium 6 beta-[D-2-(3,4-dihydroxyphenyl)-2-sulfoacetamido]-6 alpha-methoxypenicillanate (2m) as a compound with potent activity against Pseudomonas aeruginosa including beta-lactamase producing strains. Additional substitution of 2m gave derivatives 2p, 2q, 2r, with a further improvement in activity against Gram-negative bacteria.

Preparation and structure-activity relationships of some 6 alpha-substituted penicillins.

The influence on the antibacterial activity of introducing a 6 alpha-methoxy group into carbenicillin, and various 6 alpha-substituents into sulbenicillin and piperacillin was examined. Further variations of the side chain aryl group were examined in the 6 alpha-methoxy substituted series. This led to the identification of disodium 6 beta-(D,L-2-carboxy-2-thien-3-ylacetamido)-6 alpha-methoxypenicillanate (5b) as a beta-lactamase stable derivative with useful activity against Enterobacteriaceae, and disodium 6 beta-[D-2-(4-aminophenyl)-2-sulfoacetamido]-6 alpha-methoxypenicillanate (6e) with slightly lower activity against the Enterobacteriaceae but more active against Pseudomonas aeruginosa.

Use of 5-nitroindole-2'-deoxyribose-5'-triphosphate for labelling and detection of oligonucleotides.

The 5'-triphosphate of 5-nitroindole-2'-deoxyriboside has been shown to be a good substrate for terminal deoxynucleotidyl transferase (TdT). An antibody has been prepared for the detection of 5-nitroindole and has been used for the detection of 5-nitroindole tailed DNA both in single-stranded form and after hybridisation to a template. This is therefore a new method for the detection of nucleic acid probes.