Abstract
The diastereoselective synthesis of 2,3-methanophenylalanine methyl esters (5) has been achieved in 58% yield. The preparation of the dehydropeptides (1, R = Me; 2, R = H) and the cyclopropylpeptides (3, R = Me; 4, R = H) possessing good binding affinities for the CCK-A and CCK-B receptors is described. Conformational studies of the dipeptide esters 1 and 3 indicated the presence of a β-turn within the peptide backbone, although there was no preference in type. The Phe and Trp moieties, however, did prefer to be situated on the same side of the peptide turn which is favourable for receptor binding.
2,3-甲烷苯丙氨酸甲酯(5)的对映选择性合成已经以58%的产率实现。描述了具有CCK-A和CCK-B受体良好结合亲和力的脱氢肽(1,R = Me;2,R = H)和环丙肽(3,R = Me;4,R = H)的制备。二肽酯1和3的构象研究表明肽骨架内存在β-转变,尽管没有类型上的偏好。然而,Phe和Trp基团更倾向于位于肽转变的同一侧,这有利于受体结合。