Kilogram synthesis of pinoxaden. (13th September 2022)

• Record Type: Journal Article
• Authors: Jiang, Shun; Zhao, Zhiwei; Yin, Lingfeng; Wang, Han; Mao, Yongjun
• Is Part Of: Journal of heterocyclic chemistry. Volume 60:Number 2(2023)
• Page Start: 201
• Page End: 206
• Publication Date: 2022-09-13
• Subjects: Heterocyclic compounds -- Periodicals; 547.59
• DOI: 10.1002/jhet.4572
• Languages: English
• ISSNs: 0022-152X

Abstract

Abstract: An optimized kilogram‐scale synthetic route for pinoxaden was successfully developed. The key intermediate dimethyl 2‐(2, 6‐diethyl‐4‐methylphenyl)malonate (19 ) was prepared from 2, 6‐diethyl‐4‐methylaniline through diazotization reaction, Suzuki cross‐coupling reaction, and alcoholysis reaction in 59% yield over three steps in 97.3% purity. 1, 4, 5‐Oxadiazepane dihydrobromide (11 ) was obtained from diethylene glycol through esterification, cyclization, deprotection, and salification in 64% yield over three steps. Pinoxaden was given by aminolysis of 19 with 11, followed by acylation by pivaloyl chloride in 64% yield over two steps in 99.9% purity. Purification methods for the intermediates and the final product were developed. Abstract : Graphical Abstract of Pinoxaden.