The STOBBE condensation with substituted succinic esters. Part IV. A Synthesis of Substituted Naphthalene and Maleic Anhydride

Abstract

AbstractThe condensation of piperonal with dimethyl phenylsuccinate using sodium hydride as condensing agent, gave predominantly the corresponding (E)‐half‐ester 1. Cyclisation of this product led to the formation of the naphthalene derivative 2a, which upon hydrolysis produced the hydroxy acid 2b. The latter gave upon subsequent methylation and hydrolysis the naphthalene derivatives 2c, d. When benzaldehyde, p‐chioro‐, and p‐methoxy‐benzaldehydes were condensed under the above mentioned conditions, they produced the corresponding anhydrides 6a—c; which were hydrolysed to the corresponding sodium salts 9. The anhydride 6c gave with aniline the amide 7.