Synthesis and process optimization of Boscalid by catalyst Pd-PEPPSI-IPrDtBu-An

Abstract

The purpose of this research was to reduce the amount of noble metal palladium catalyst and improve the catalytic performance in the Suzuki–Miyaura cross-coupling reaction, which is the key step in the synthesis of Boscalid. Taking o-bromonitrobenzene and p-chlorophenylboronic acid as raw materials, three kinds of Pd-PEPPSI-IPr catalysts were synthesized and employed in the Suzuki reaction, and then the biaryl product was subjected to reduction and condensation reaction to give Boscalid. Under the optimal reaction conditions, the result showed that the catalytic system exhibits highest catalytic efficiency under aerobic conditions, giving the 2-(4-chlorophenyl)nitrobenzene in over 99 % yield. Moreover, the Pd-PEPPSI-IPrDtBu-An catalyst was minimized to 0.01 mol%. The synthesis process was mild, the post-treatment was simple, and the production cost was reduced, which makes it suitable for industrial production.