{[[K.18-Crown-6]Br3}n: A tribromide catalyst for the catalytic protection of amines and alcohols
作者:Gholamabbas Chehardoli、Mohammad Ali Zolfigol、Fateme Derakhshanpanah
DOI:10.1016/s1872-2067(12)60644-5
日期:2013.9
[K.18-Crown-6]Br3}n, a unique tribromide-type catalyst, was utilized for the N-boc protection of amines and trimethylsilylation (TMS) and tetrahydropyranylation (THP) of alcohols. The method is general for the preparation of N-boc derivatives of aliphatic (acyclic and cyclic) and aromatic, and primary and secondary amines and also various TMS-ethers and THP-ethers. The simple separation of the catalyst
Nano-ferrous ferric oxide (nano-Fe3O4): Powerful, reusable, and stable catalyst for N-Boc protection of amines
作者:Mohammad Ali Zolfigol、Ahmad Reza Moosavi-Zare、Parvin Moosavi、Vahid Khakyzadeh、Abdolkarim Zare
DOI:10.1016/j.crci.2013.05.010
日期:2013.11
Résumé Nano-ferrous ferric oxide (nano-Fe3O4) efficiently catalyzed N-boc protection of amines in high yields and acceptable reaction times. Nano-Fe3O4 was applied as an efficient, green, heterogeneous and reusable magnetite catalyst. Clean reaction, simple purification, short reaction time and high yield were some other advantages of this compound.
A simple and efficient method for the chemoselective N-Boc protection of the amine moiety in a variety of compounds is described using di-tert-butyl dicarbonate and guanidine hydrochloride as an organocatalyst in ethanol at 35-40 degrees C. Selective mono-N-Boc protection of diamines and chemoselective protection of hydroxylamines without formation of any side products is achieved. Amino acids and peptides are N-Boc protected efficiently in excellent yields under convenient reaction conditions. (C) 2011 Elsevier Ltd. All rights reserved.