The pentacyclic guanidine compounds 4 and 5 were stereoselectively synthesized as novel ptilomycalin A and crambescidin analogs. The synthetic method involves successive 1,3-dipolar cycloaddition reactions which effectively access the key intermediates, trans- and cis-2,5-disubstituted pyrrolidine 8 having hydroxyl groups at the β-positions on their side chains. Among the analogs synthesized, 4b and 5b exhibited significant inhibitory activity against Ca2+-ATPase.
五环
胍类化合物4和5被立体选择性合成为新型ptilomycalin A和crambescidin类似物。合成方法涉及连续的1,3-偶极环加成反应,有效获取了关键中间体trans-和cis-2,5-二取代
吡咯烷8,它们的侧链在β位具有羟基。在合成的类似物中,4b和5b表现出了显著的Ca2+-
ATP酶抑制活性。