Many compounds containing a -CONH- group display photosynthesis inhibiting activity. Based on this structural feature, a group of anilides of 2-alkylthio-(1b-4f) or 2-chloro-6-alkylthio-4-pyridinecarboxylic acids (5a-6c) was synthesised. The prepared compounds were tested for their inhibition of the oxygen evolution rate (OER) in spinach chloroplasts. A quasi-parabolic dependence between photosynthesis-inhibiting activity and the lipophilicity of the compounds was determined for 1b-4f as well as for 5a-6c. The inhibitory activity of compounds 1b-4f was higher than that of 5a-6c for comparable lipophilicity values.
A group of 26 new 2-halogeno-6-alkylsulfanyl- and 2,6-bis-alkylsulfanyl-4-amidopyridines and corresponding thioamidopyridines was synthesised. Some of the amidopyridines and all thioamidopyridines were tested for their antimycobacterial activity against atypical mycobacterial strains. Promising photosynthesis-inhibiting activity was also found for some of the amidopyridines.