2114-11-6Relevant articles and documents
Direct palladium-mediated on-resin disulfide formation from Allocam protected peptides
Kondasinghe, Thilini D.,Saraha, Hasina Y.,Odeesho, Samantha B.,Stockdill, Jennifer L.
, p. 2914 - 2918 (2017)
The synthesis of disulfide-containing polypeptides represents a long-standing challenge in peptide chemistry, and broadly applicable methods for the construction of disulfides are in constant demand. Few strategies exist for on-resin formation of disulfides directly from their protected counterparts. We present herein a novel strategy for the on-resin construction of disulfides directly from Allocam-protected cysteines. Our palladium-mediated approach is mild and uses readily available reagents, requiring no special equipment. No reduced peptide intermediates or S-allylated products are observed, and no residual palladium can be detected in the final products. The utility of this method is demonstrated through the synthesis of the C-carboxy analog of oxytocin.
An Fe3O4@SiO2/Schiff base/Cu(ii) complex as an efficient recyclable magnetic nanocatalyst for selective mono: N-arylation of primary O-alkyl thiocarbamates and primary O-alkyl carbamates with aryl halides and arylboronic acids
Sardarian, Ali Reza,Dindarloo Inaloo, Iman,Zangiabadi, Milad
, p. 8557 - 8565 (2019/06/14)
An efficient, convenient and novel method for the selective mono N-arylation of primary O-alkyl thiocarbamates and primary O-alkyl carbamates with aryl halides and arylboronic acids in the presence of a recyclable magnetic Cu(ii) nanocatalyst is described. A variety of mono N-arylated O-alkyl thiocarbamates and O-alkyl carbamates were prepared in good to excellent yields with a broad range of aryl coupling partners. The magnetic nanocatalyst can be easily recovered with an external magnetic field and reused at least five times without noticeable leaching or loss of its catalytic activity. This cost-effective and eco-friendly methodology has some other advantages, such as easy preparation of the catalyst, simple workup procedure, and easy purification, which makes this protocol interesting for the users in various fields of pharmacology and biotechnology systems.
Superparamagnetic Fe3O4 Nanoparticles in a Deep Eutectic Solvent: An Efficient and Recyclable Catalytic System for the Synthesis of Primary Carbamates and Monosubstituted Ureas
Inaloo, Iman Dindarloo,Majnooni, Sahar,Esmaeilpour, Mohsen
, p. 3481 - 3488 (2018/07/29)
Superparamagnetic Fe3O4 nanoparticles were used to synthesize various primary carbamates as well as monosubstituted and N,N-disubstituted ureas. This efficient phosgene-free process used urea as an eco-friendly carbonyl source in the presence of a biocompatible deep eutectic solvent (DES) to provide an inexpensive and attractive route that afforded the products in moderate to excellent yields. The employed DES serves both a catalytic role and as the green reaction medium. The magnetic nanocatalyst and DES can been reused several times without a significant loss of activity.
4-Dodecylbenzenesulfonic acid (DBSA) promoted solvent-free diversity-oriented synthesis of primary carbamates, S-thiocarbamates and ureas
Sardarian, Ali Reza,Inaloo, Iman Dindarloo
, p. 76626 - 76641 (2015/09/22)
A simple and highly efficient solvent-free method for the conversion of alcohols, phenols, thiols and amines to primary carbamates, S-thiocarbamates and ureas in the presence of 4-dodecylbenzenesulfonic acid (DBSA) as a cheap and green Bronsted acid reagent has been described. All products were obtained in good to excellent yields and characterized using FT-IR, 1H- and 13C-NMR, MS and CHNS techniques.
Substrate scope and stereocontrol in the Rh(II)-catalysed oxyamination of allylic carbamates
Unsworth, William P.,Lamont, Scott G.,Robertson, Jeremy
, p. 7388 - 7394 (2017/09/12)
Application of a modified Du Bois protocol for rhodium-stabilised nitrenoid generation to a variety of allylic carbamates results in 4-acetoxymethyl-1,3-oxazolidin-2-one derivatives with moderate to high levels of stereocontrol.
FORMING POROUS SCAFFOLD FROM CELLULOSE DERIVATIVES
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, (2013/02/28)
Scaffold comprises a polymer defining macropores and comprising hydroxypropylcellulose partially substituted by a substituent comprising a self-crosslinkable group, which is crosslinked through the self-crosslinkable group. The macropores have an average pore size larger than 50 microns and are at least partially interconnected. In one method, bicontinuous emulsion comprising a continuous aqueous phase and a continuous polymer phase is formed. The polymer phase comprises hydroxypropylcellulose partially substituted by a substituent comprising a self-crosslinkable group, and is crosslinked through the self-crosslinkable group to form a polymer defining at least partially interconnected pores. In another method, phase separation is induced in a solution comprising a polymer precursor and water to form a bicontinuous emulsion comprising a continuous polymer phase and a continuous aqueous phase. The polymer precursor comprises a self-crosslinkable group and is crosslinked through the self-crosslinkable group in the emulsion to form a polymer defining at least partially interconnected macropores.
Modifications of the C6-substituent of penicillin sulfones with the goal of improving inhibitor recognition and efficacy
Nottingham, Micheal,Bethel, Christopher R.,Pagadala, Sundar Ram Reddy,Harry, Emily,Pinto, Abishai,Lemons, Zachary A.,Drawz, Sarah M.,Akker, Focco Van Den,Carey, Paul R.,Bonomo, Robert A.,Buynak, John D.
scheme or table, p. 387 - 393 (2011/03/17)
In order to evaluate the importance of a hydrogen-bond donating substituent in the design of β-lactamase inhibitors, a series of C6-substituted penicillin sulfones, lacking a C2′ substituent, and having an sp 3 hybridized C6, was prepared and evaluated against a representative classes A and C β-lactamases. It was found that a C6 hydrogen-bond donor is necessary for good inhibitory activity, but that this feature alone is not sufficient in this series of C6β-substituted penicillin sulfones. Other factors which may impact the potency of the inhibitor include the steric bulk of the C6 substituent (e.g., methicillin sulfone) which may hinder recognition in the class A β-lactamases, and also high similarity to the natural substrates (e.g., penicillin G sulfone) which may render the prospective inhibitor a good substrate of both classes of enzyme. The best inhibitors had non-directional hydrogen-bonding substituents, such as hydroxymethyl, which may allow sufficient conformational flexibility of the acyl-enzyme for abstraction of the C6 proton by E166 (class A), thus promoting isomerization to the β-aminoacrylate as a stabilized acyl-enzyme.
Silica supported perchloric acid (HClO4-SiO2): an efficient reagent for the preparation of primary carbamates under solvent-free conditions
Modarresi-Alam, Ali Reza,Khamooshi, Ferydoon,Nasrollahzadeh, Mahmoud,Amirazizi, Homeyra Alsadat
, p. 8723 - 8726 (2008/02/11)
The synthesis of primary carbamates from structurally diverse compounds containing a hydroxyl group has been performed in high yields and purity, and without any epimerization under solvent-free conditions using HClO4-SiO2 as a mild, convenient, and effective reagent. The procedure is operationally simple, efficient, and environmentally benign.
