Cyclic Dipeptides. 3.<sup>1</sup> Synthesis of Methyl (<i>R</i>)-6-[(<i>tert</i>-Butoxycarbonyl)amino]-4,5,6,7- tetrahydro-2-methyl-5-oxo-1,4-thiazepine-3-carboxylate and Its Hexahydro Analogues: Elaboration of a Novel Dual ACE/NEP Inhibitor
作者:Angela Crescenza、Maurizio Botta、Federico Corelli、Antonello Santini、Andrea Tafi
DOI:10.1021/jo981425v
日期:1999.4.1
Synthetic routes to highly functionalized 1,4-thiazepinones 2 and 3 have been developed. S-Ac-N-Boc-L-Cys-D(L)-ThrOMe 7a,b have been prepared and, after transformation into the corresponding mesylates, used as the cyclization substrates. Treatment of these compounds with LiAlH(OMe)(3) in THF results in mesylate elimination and thiolacetate reduction, giving rise to both a Michael acceptor (alpha,beta-unsaturated
已经开发出合成高度官能化的1,4-噻嗪酮2和3的途径。已经制备了S-Ac-N-Boc-L-Cys-D(L)-ThrOMe 7a,b,并且在转化成相应的甲磺酸酯之后,用作环化底物。在THF中用LiAlH(OMe)(3)处理这些化合物会导致甲磺酸酯消除和硫醇乙酸酯还原,同时产生迈克尔受体(α,β-不饱和酯)和迈克尔供体(硫醇阴离子),它们会原位经历分子内共轭加成导致2的四个可能的立体异构体中只有两个的立体选择性形成。另一方面,7a的PCC / CaCO(3)氧化产生80%的产率的相应的酮11,其继而转化为烯醇三氟甲磺酸酯15.切割硫羟乙酸酯部分,通过MeONa / MeOH的一锅反应实现了同时消除三氟甲磺酸以生成烯丙基体系,以及将硫醇基团添加到烯丙基的中心碳上以提供对映体纯的环状化合物3,产率为85%。 。噻嗪酮3是制备构象受限的二肽模拟物的令人感兴趣的中间体,并且报道了其被合成为双重ACE /