2-(Chloromethyl)-4H-1,3,2-benzodioxaphosphorin 2-sulfide 4H-1,3,2-Benzodioxaphosphorin, 2-(chloromethyl)-, 2-sulfide DF4370500 Phosphonothioic acid, (chloromethyl)-, cyclic O,O-ester with o-hydroxybenzyl alcohol