Tao Yang, Jiaxuan Chen, Yiwei Fu
Mar 18, 2014
Citations
1
Influential Citations
9
Citations
Journal
Organic Process Research & Development
Abstract
A concise, environmentally benign, and cost-effective route was developed for the large-scale preparation of 1, a novel oxazolidinone antibacterial candidate. The key intermediate 2-(1-(2-fluoro-4-nitrophenyl)-1H-pyrazol-4-yl)pyridine 7 was prepared with high purity by mild deamination of the regioisomeric mixture 21. The mixture was prepared from a nucleophilic SNAr reaction by selective C–N coupling of the secondary amine functionality of 4-(pyridin-2-yl)-1H-pyrazol-3-amine 14 with 1,2-difluoro-4-nitrobenzene 10 in optimized conditions with the primary amine group remaining intact. The gaseous nitrogen release rate and reaction mixture temperature of the deamination step can be well controlled by altering the feeding manner, thereby providing safety guarantees. The optimized synthetic strategy of 1 with an overall yield of 27.6%, including seven sequential transformations by only five solid–liquid isolations, significantly improved the product separation workup. The strategy bypassed time-consuming and ...