Abstract: The ¹H NMR data of N-(6-methyl-2 -benzothiazolyl)-α-aminoalkylphosphonic acid diethyl esters are reported, and the substituent effects of α-benzene ring on chemical shifts of α-CH are studied. The crystal structure of one of the title compounds is determined by X-ray diffraction. The two ethoxys of the phosphonates are magnetically nonequivalent, which is caused by the different shielding effects of α-benzene on the two ethoxy groups. The substituent effects of α-benzene on the shielding effect of α-benzene is studied, and the configurational superposition of different molecules is made to elucidate the effect of orthosubstituent on the shielding effect of α-benzene.

Key words: ¹H NMR, X-ray diffraction, α-aminoalkylphosphonic acid diethyl ester, Optimum configuration