Abstract: The C₂ deoxy and C₆ electron isosterie analogs of a new antiglaucoma agent, erycibe alkaloid Ⅱ, were designed and synthesized. The main pharmacological results were as follows: 1. The C₂-OH in erycibe alkaloid Ⅱ was one of the key groups for its myotic activity; 2. It was worth noting that compounds 2 and 4 showed cholinergie and anticholinergic activities, respectively. This phenomenon in tropane alkaloids was not reported before; 3. The C₆ electron isosteric compounds 16 and 17 showed neither anticholinergic nor cholinergic activities.