US 11,655,220 B2
Process for the preparation of angiotensin II receptor blockers
Kura Rathnakar Reddy, Hyderabad (IN); Nagabelli Murali, Hyderabad (IN); and Nimmanapalli Pullareddy, Hyderabad (IN)
Assigned to Hetero Labs Limited, Hyderabad (IN)
Filed by Hetero Labs Limited, Hyderabad (IN)
Filed on Apr. 7, 2021, as Appl. No. 17/224,753.
Claims priority of application No. 202041046037 (IN), filed on Oct. 22, 2020.
Prior Publication US 2022/0127238 A1, Apr. 28, 2022
Int. Cl. C07D 257/04 (2006.01)
CPC C07D 257/04 (2013.01) 6 Claims
 
1. A process for preparing a 5-substituted tetrazole comprising reacting a nitrile compound of Formula II
R—CN  Formula II
with an inorganic azide and zinc halide in an ether solvent, and optionally hydrolyzing a compound obtained thereby, wherein:
(a) the 5-substituted tetrazole is free of nitrosamine impurities;
(b) the 5-substituted tetrazole is represented by Formula I

OG Complex Work Unit Chemistry
wherein R is

OG Complex Work Unit Chemistry
and
R″ is alkyl; R′″ is alkanoyl; and
(c) the process is carried out in the absence of amines and nitrites.