4242-21-1 4H-1,3,2-Benzodioxaphosphorin, 2-phenyl-, 2-oxide AI3-27200 BRN 2561900 K 1 (pesticide) Phenylphosphonic acid cyclic methylene-o-phenylene ester Phosphonic acid, phenyl-, cyclic ester with o-hydroxybenzyl alcohol (7CI) Phosphonic acid, phenyl-, cyclic methylene-o-phenylene ester