在天然物中，具五或六圓環之azasugars多為glycosidase之抑制劑。然而，近年來發現具七圓環結構的azasugars，即所謂的azepanes(polyhydroxyazepanes)，較前二類分子更有潛力發展成為糖尿病、抗HIV、抗病毒的藥物，因為其構形較五或六圓環之azasugars更易嵌入DNA之minor grove。 類似trihydroxyazepanes的分子在文獻上出現的次數並不多，本實驗以既便宜且易取得的D-(-)-quinic acid為起始物，共經10個反應步驟，得到一系列具有立體化學特異性的3,4,6-trihydroxyaze-panes標的物。藉由和tetrahydroxyazepanes之生物活性作比較，進而了解azasugars中官能基的位置、數目及立體化學對醣水解酵素抑制性的影響。 The naturally occurring five- and six-membered azasugars are considered as glycosidase inhibitors. Most recently, the seven-membered azasugars(poly-hydroxyazepanes) were reported to have potential in treatment of diabetes, cancers and AIDS. These heterocycles are more flexible in conformation than the corresponding six- and five-membered counterparts and may bind in the minor groove of DNA.
Little attention has been given to trihydroxyazepanes. We wish to describe herein a new approach to the synthesis of diastereomeric azasugars (3,4,6-trihydroxyazepanes) in ten steps each from the commercially available D-(-)-quinic acid. The biological test of this series of 3,4,6-trihydroxyazepanes and their derivatives allows us to compare with their corresponding tetrahydroazepanes. Especially, we can further learn the structure relationship regarding to the stereochemistry of hydroxy groups.
