A Simple Synthesis of Nβ-Fmoc/Z-Amino Alkyl Thiols and their use in the Synthesis of Nβ-Fmoc/Z-Amino Alkyl Sulfonic Acids
作者:V. Sureshbabu、T. Vishwanatha、B. Vasantha
DOI:10.1055/s-0029-1219584
日期:2010.4
simple and efficient protocol for the synthesis of N β -Fmoc/Z-amino alkylthiols is described. The approach uses sodium pyrosulfite-mediated hydrolysis of isothiouronium salts resulting from the reaction between N-protected aminoalkyl iodides and thiourea. N-Protected taurines were prepared through performic acid oxidation of the thiols and the products were further utilized for the synthesis of dipeptidosulfonamides
<i>N</i>-Urethane-Protected Amino Alkyl Isothiocyanates: Synthesis, Isolation, Characterization, and Application to the Synthesis of Thioureidopeptides
作者:Vommina V. Sureshbabu、Shankar A. Naik、H. P. Hemantha、N. Narendra、Ushati Das、Tayur N. Guru Row
DOI:10.1021/jo900675s
日期:2009.8.7
Synthetically useful N-Fmoc amino-alkyl isothiocyanates have been described, starting from protected amino acids. These compounds have been synthesized in excellent yields by thiocarbonylation of the monoprotected 1,2-diamines with CS2/TEA/p-TsCl, isolated as stable solids, and completely characterized. The procedure has been extended to the synthesis of amino alkyl isothiocyanates from Boc- and Z-protected amino acids as well. The utility of these isothiocyanates for peptidomimetics synthesis has been demonstrated by employing them in the preparation of a series of dithioureidopeptide esters. Boc-Gly-OH and Boc-Phe-OH derived isothiocyanates 9a and 9c have been obtained as single crystals and their structures solved through X-ray diffraction. They belong to the orthorhombic crystal system, and have a single molecule in the asymmetric unit (Z' = 1). 9a crystallizes in the centrosymmetric space group Pbca, while 9c crystallizes in the noncentrosymmetric space group P2(1)2(1)2(1).
Hydrodehalogenation of Alkyl Iodides with Base-Mediated Hydrogenation and Catalytic Transfer Hydrogenation: Application to the Asymmetric Synthesis of N-Protected α-Methylamines
作者:Pijus K. Mandal、J. Sanderson Birtwistle、John S. McMurray
DOI:10.1021/jo500911v
日期:2014.9.5
We report a very mild synthesis of N-protected α-methylamines from the corresponding amino acids. Carboxyl groups of amino acids are reduced to iodomethyl groups via hydroxymethyl intermediates. Reductive deiodination to methyl groups is achieved by hydrogenation or catalytic transfer hydrogenation under alkaline conditions. Basic hydrodehalogenation is selective for the iodomethyl group over hydrogenolysis-labile