Crystal structure of diethyl 1-(6-methyl-2-benzothiaylamino)-2,4-dichlorophenylmethylphosphonate

The crystal and molecular structure of diethyl 1-(6-methyl-2-benzothiazolea mino)-2,4-dichlorophenylmethylphosphonate has been determined by X-ray diff raction method. The crystal (C19H21Cl2N2O3PS) is monoclinic with space grou p p2(1)/c, a=8.318(2), b=18.202(4), c=14.673(3) Angstrom, beta=92.51(3)degr ees, mu=0.4749 mm(-1), Z=4; D-x=1.375 g/cm(3), F(000)=952, V=2219(1) Angstr om(3), final R=0.059 and R-w=0.060 for 2038 observed reflections with I gre ater than or equal to 3 sigma(I). The X-ray analysis result shows that the magnetic nonequivalence of the two ethoxy groups of the title compound is c aused by the shielding effect of the benzene ring in alpha-position.