In order to complete the SAR and discover new potent and selective PCOs, some changes were made to the C-4 and C-2 substitutions of cromakalim. A series of 4 -amino acid substituted -2, 2-dialkylchromans structurally related to cromakalim were synthesized and evaluated, as ATP-sensitive potassium channel openers (8a-l). Preliminary biological tests suggested that these compounds exhibited potent to mild relaxation activity of the KCl-contracted rat aortic strips. Compounds 8b (IC50 =0.25μM), 8f (IC50 =6.44μM) and 8j (IC50 =8.65μM) exhibited commendable opening activity of potassium channels. In addition to anti-hypertension, these compounds can also be considered as lead candidates for the further development of myocardial antiischemic drugs.