The cleavage of 1-amino-2'-nitrobenzylphosphonates in a basic medium. Formation of the 3-amino-2,1-benzisoxazole derivatives

Article abstract of DOI:10.1016/S0040-4020(97)00721-7

Treatment of 1-amino-2'-nitrobenzylphosphonic acids with aqueous sodium hydroxide caused a C-P bond cleavage, with formation of 3-amino-2,1-benzisoxazole derivatives (3). The leaving phosphorus moiety was identified here as phosphoric acid. In the case of basic hydrolysis of corresponding esters, new cyclic phosphorus compounds (derivatives of benzoxazaphosphorin-3,1,2 P(v)-one-2) were obtained. The cyclic products were formed as a result of the subsequent reaction of anthranil derivatives with leaving phosphorus fragment, presumably metaphosphate, These benzoxazaphosphorins (cormpounds 4) were converted by means of aqueous hydrochloric acid to 3-amino-2,1-benzisoxazole derivatives.