The reaction of Wittig and Wittig-Horner reagents and alkyl phosphites with 1,2-naphthoquinone-1-benzimide

Carbomethoxymethylene and carbethoxymethylene triphenylphosphoranes (1a, b) react with 1,2-naphthoquinone-1-benzimide (8) to give the corresponding 1-benzoylimino-1H-naphthalen-2-ylidene-acetic esters 9a,b and 2-(1-benzoylamino-naphthalen-2-yl)-but-2-enedioic esters 10a,b together with 1-benzamido-2-naphthol (11). Application of Wittig-Homer reagents 4a,b on 8 at room temperature and in the presence of alcoholic sodium alkoxide renders 2-(1-benzoylaminonaphthalen-2-yl)-3-phosphonylsuccinic esters 12a,b. Conducting the reaction in refluxing toluene and in the presence of sodium hydride led to the formation of 2-benzamido-naphthol-1-ethyl ether (13). 1-Benzamido-2-naphthol (11) was also isolated from both reaction media. Trimethyl and dimethyl phosphites (7a,b) react with 8 to 14 as the sole product. Mechanisms accounting for the formation of the new products are discussed, and the probable structures of the products are presented based on analytical and spectroscopic data.