... Volume: Page ... and several analogues described as potassium channel openers: BPDZ 44, BPDZ 83, BPDZ 73 and its quinazolinone isostere (5) in two possible tautomeric ... a (i) ClSO 2 NCO, CH 3 NO 2 , AlCl 3 ; (ii) P 2 S 5 , pyridine, Δ; (iii) NaHCO 3 , CH 3 I, CH ...