Selective deprotection of phenacyl, benzyl and methyl esters of N-protected amino acids and dipeptides and N-protected amino acids benzyl ester linked to resins with bis(tributyltin) oxide
作者:Claudio J. Salomon、Ernesto G. Mata、Oreste A. Mascaretti
DOI:10.1039/p19960000995
日期:——
methyl and benzyl esters of variousN-α-Boc, N-α-Cbz or N,N-dimethylamino protected amino acids and dipeptides, as well as esters of N-α-protected amino acids linked to Wang and Pam resins have been efficiently and chemoselectively cleaved by bis(tributyltin) oxide in aprotic solvents to give the corresponding carboxylic acids in good yields. Moreover, the absence of racemization during the deprotection
各种N -α-Boc,N -α-Cbz或N,N-二甲基氨基保护的氨基酸和二肽的苯甲酸酯,甲基和苄基酯以及与Wang和Pam树脂连接的N -α保护的氨基酸的酯具有在非质子溶剂中用双(三丁基锡)氧化物有效地和化学选择性地裂解该化合物,从而以良好的收率得到相应的羧酸。此外,已经证明在脱保护过程中不存在外消旋作用。该方法的一个限制是不稳定Ñ -Îμ-Fmoc基团的氨基酸酯8和10,Ñ -α-的Fmoc-大号β-丙氨酸连接于王氏树脂23和Cbz基保护基团在Ñ-α-的Boc-N-Iμ-CBZ-大号赖氨酸苄基和甲酯(5和7),分别与Ñ -α-CBZ-大号-alanyl-大号丙氨酸甲酯19的情况下Ñ -在α-保护的二肽中,没有游离氨基酸的迹象表明该肽键不受影响。