QSAR Study Concerning Photosynthesis Inhibition in Algae and Plant Chloroplasts by 2-Alkylthio-6-R- benzothiazoles

Activity of 2-alkylthio-6-aminobenzothiazoles and their 6-A/-substituted derivatives (3-(2-alkylthio6-benzothiazolylaminomethyl)-2-benzothiazolinethiones and 3-(2-alkylthio-6-benzothiazolylaminomethyl)-6-bromo-2-benzothiazolinones) concerning photosynthesis inhibition in algae Chlorella vulgaris and in spinach chloroplasts has been correlated with lipophilicity and dipóle moments of the effectors using the Hansch method. Parameters of the Hansch equation were calculated by theoretical methods. The benzene and the thiazole rings of 2-alkylthio-6-R-benzothiazoles are the electron-donor part of the investigated benzothiazole effectors. Antialgal activity of the com­ pounds of the series containing bromine showed relatively high efficiency for all investigated derivatives with negligible differences.