2H-1,2,3,4-tetrazole-5-carboxylic acid

2H-1,2,3,4-Tetrazole-5-carboxylic acid (CAS 75773-99-8) is a high-purity, nitrogen-rich heterocyclic building block engineered for bioisosteric applications in medicinal chemistry and agrochemical development . This molecule integrates a 1,2,3,4-tetrazole core—a pentazole ring system with exceptional metabolic stability and hydrogen-bonding capacity—with a carboxylic acid substituent at the C5 position. The tetrazole ring serves as a privileged bioisostere for carboxylic acids, cis-amides, and oxadiazoles, offering enhanced metabolic stability, improved membrane permeability, and unique electronic properties compared to conventional aromatic systems . The C5-carboxylic acid moiety enables direct amide coupling, salt formation for solubility enhancement, or decarboxylative cross-coupling strategies. This intermediate is particularly valuable for constructing kinase inhibitor cores, angiotensin II receptor antagonists for hypertension treatment, and agrochemical actives where the tetrazole-carboxylate motif optimizes target engagement and pharmacokinetic profiles . Manufactured under controlled conditions , it supports drug discovery programs requiring modular access to nitrogen-dense heterocyclic architectures with tunable acidity and hydrogen-bonding geometry.