An efficient, telescopic, and scalable process for an antihypertensive drug substance, valsartan with an overall yield of 58%, and 99.9% purity is described. A simple, and safe process is developed for the recovery of tributyltin chloride from the tributyltin hydroxide, byproduct formed in the tetrazole ring construction, and reused in the synthesis of valsartan.
Dr. Reddy’s Laboratories
Org. Process Res. Dev., 2012, 16 (4), pp 682–686