Analogues of the dibasic antiarrhythmic agent disobutamide (2) were prepared and evaluated for antiarrhythmic efficacy, myocardial depression, and anticholinergic activity. The replacement of an isopropyl group in disobutamide by an acetyl group led to the monobasic analogue SC-40230, 7a, which demonstrated good antiarrhythmic activity accompanied by less myocardial depressant and anticholinergic activities. In addition, it ...