A simple protocol for the synthesis of triazole-linked cyclic glycopeptidomimetics: A sequential Ugi-MCR and azide-alkyne cycloaddition approach

Sequential combination of Ugi-MCR and click chemistry has been employed for the synthesis of triazole linked cyclic glycopeptidomimetics. The protocol employs Poc-amino alkyl isonitriles, sugar-1-amines, azido acids, and simple aldehydes as precursors. The dual nature of the propargyloxycarbonyl (Poc) group was explored for amine protection as well as cycloaddition with an azide. All the cyclic glycopeptidomimetics are isolated and characterized. © 2012 Elsevier Ltd. All rights reserved

Facile N-​urethane-​protected α-​amino​/peptide thioacid preparation using EDC and Na2S

We report herein an efficient protocol for the synthesis ofN-urethane-protected a-amino/peptide thioacids from their correspondingacids mediated by EDC and Na2S. The fast reaction undermild conditions enabled the process to be completed in shorter durationwith good yield circumventing column purification. Thechemistry is compatible with a wide variety of urethane protecting groups, side-chain functionalities, and sterically hindered amino acids

A simple and greener approach for the synthesis of PVC supported Pd (0): Application to Heck and Sonogashira reactions in water

Preparation of PVC-supported Pd nanoparticles through the reduction of PdCl2 by a non-toxic and eco-friendly route, employing sodium formate and NaOH in ethanol-water system has been described. The prepared PVC supported Pd nanoparticles were employed as catalyst in the cross coupling reactions, that is, Heck and Sonogashira reactions in water medium to afford the respective products in good to excellent yields. © 2014 Elsevier Ltd. All rights reserved

3,3-Dichloro-1,2-diphenylcyclopropene (CPICl)-Mediated Synthesis of N alpha-Protected Amino Acid Azides and alpha-Ureidopeptides

Rapid synthesis of acid azides via in situ generation of acid chlorides using CPICl as chlorinating agent from the corresponding N-alpha-protected amino acids is described. Also the conversion of acid azides into ureidopeptides through the Curtius rearrangement under ultrasonication is delineated. The mildness of the protocol renders the acid-sensitive substrates to afford the corresponding amino acid azides and ureidopeptides in good yields. Diphenylcyclopropenone has also been recovered from the reaction mixture and reused

3,​3-​dichloro-​1,​2-​diphenylcyclopropene (CPICl)​-​mediated synthesis of Nα-​protected amino acid azides and α-​ureidopeptides

Rapid synthesis of acid azides via in situ generation of acid chlorides using CPICl as chlorinating agent from the corresponding Nα -protected amino acids is described. Also the conversion of acid azides into ureidopeptides through the Curtius rearrangement under ultrasonication is delineated. The mildness of the protocol renders the acid-sensitive substrates to afford the corresponding amino acid azides and ureidopeptides in good yields. Diphenylcyclopropenone has also been recovered from the reaction mixture and reused

Design and Synthesis of a Novel N-(1H-tetrazol-5-yl)methyl Cyclic Peptoid Using Nosyl-protected N-(1-trityl-1H-tetrazol-5-yl)methyl Substituted Glycine

Abstract: A solid phase synthesis of a cyclic peptoid bearing (1H-tetrazol-5-yl)methyl as N-substituent has been developed employing the monomer approach. The requisite monomeric Nosyl-protected N-(1-trityl-1H-tetrazol-5-yl)methyl substituted glycine was accessed by a convenient synthesis involving Click reaction of Nosyl-protected N-(cyanomethyl)glycine methyl ester and sodium azide as a key step. This building block was then employed in the solid phase synthesis of a tetramer peptoid. The linear tetramer was subjected to macrocyclization using PyBOP to obtain a cyclic peptoid with (1H-tetrazol-5-yl)methyl pendants in good yield. © 2017, Springer Science+Business Media New York

Observation of a reversible isomorphous phase transition and an interplay of "sigma-holes'' and "pi-holes'' in Fmoc-Leu-psi[CH2-NCS]

Fmoc-Leu-psi[CH2NCS] undergoes a reversible isomorphous phase transition upon cooling. The crystal structure at 100 K displays a short N=C=S center dot center dot center dot N=C=S intermolecular interaction, which has been characterized based on experimental charge density analysis, as a stabilizing interaction with both sigma-holes and pi-holes acting cooperatively

Facile N-urethane-protected α-amino/peptide thioacid preparation using EDC and Na 2S

We report herein an efficient protocol for the synthesis of N-urethane-protected α-amino/peptide thioacids from their corresponding acids mediated by EDC and Na 2S. The fast reaction under mild conditions enabled the process to be completed in shorter duration with good yield circumventing column purification. The chemistry is compatible with a wide variety of urethane protecting groups, side-chain functionalities, and sterically hindered amino -acids. © Georg Thieme Verlag Stuttgart. New York