Benzothiadiazine Dioxides - A New Class Of Potent Angiotensin-Ii (At-1) Receptor Antagonists

N-Biphenylmethyl benzothiadiazine dioxides were prepared as potential angiotensin-II receptor antagonists. Stability of the compounds is dependent upon the nature of the substituent at position 3 of the benzothiadiazine ring, while potency is dependent upon the nature of substitution in the benzo fused ring. 3-(Propylthio)-4-[2'-(2H-tetrazol-5-yl)[1,1'-biphenyl]-4-ylmethyl]-4H-1,2,4-benzothiadiazine-6-carboxylic acid, 1,1-dioxide (17) is one of the most potent examples, with functional activity (KB) below 0.1 nM.