Abstract
2-Amino-2-arylethylphosphonic acids, 6a to 6q have been prepared from the corresponding 2-acetoxyimino-or 2-methoxyimino-2-aryl-ethylphosphonates, 3 or 4, by hydrogenation using Raney-Ni as a catalyst, followed by hydrolysis with HCl. 3 and 4 were obtained from the corresponding aryl-bromomethyl-ketoxime-O-acetates, 1, or aryl-bromomethyl-O-methylketoximes, 2, by an Arbuzov reaction with triethylphosphite. Several of the 2-amino-2-arylethylphosphonic acids 6 show activity against Botrytis cinerea and Cercospora. Among the more active compounds were 6a, 6b, 6g and 6k, whereby 6b and 6k gave full protection against Botrytis cinerea (on apple) down to 60 ppm. The same compounds show also a weak inhibition of anthocyanin synthesis in vivo.