Some anilides of 2-alkylthio- and 2-chloro-6-alkylthio-4-pyridinecarboxylic acids: Synthesis and Photosynthesis-inhibiting activity

Many compounds containing a -CONH- group display photosynthesis inhibiting activity. Based on this structural feature, a group of anilides of 2-alkylt hio-(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 dep endence between photosynthesis-inhibiting activity and the lipophilicity of the compounds was determined for 1b-4f as well as for 5a-6c. The inhibitor y activity of compounds 1b-4f was higher than that of 5a-6c for comparable lipophilicity values.