Preparation of 2-(1H-pyrazol-5-yl)benzenesulfonamides from polylithiated C(α),N-carbo-tert-butoxyhydrazones and methyl 2-(aminosulfonyl)benzoate

Select C(α), N-carbo-tert-butoxyhydrazones were dilithiated with excess lithium diisopropylamide followed by condensation with methyl 2-(aminosulfonyl)benzoate, acid cyclization, hydrolysis, and decarboxylation to afford new 2-(1H-pyrazol-5-yl)benzenesulfonamides, [NH-pyrazolyl-ortho-benzene-sulfonamides].