Nonsolvent Application of Ionic Liquids: Organo-Catalysis by 1-Alkyl-3-methylimidazolium Cation Based Room-Temperature Ionic Liquids for Chemoselective <i>N</i>-<i>tert</i>-Butyloxycarbonylation of Amines and the Influence of the C-2 Hydrogen on Catalytic Efficiency
作者:Anirban Sarkar、Sudipta Raha Roy、Naisargee Parikh、Asit K. Chakraborti
DOI:10.1021/jo201102q
日期:2011.9.2
1-Alkyl-3-methylimidazolium cation based ionicliquids efficiently catalyze N-tert-butyloxycarbonylation of amines with excellent chemoselectivity. The catalytic role of the ionicliquid is envisaged as “electrophilic activation” of di-tert-butyl dicarbonate (Boc2O) through bifurcated hydrogen bond formation with the C-2 hydrogen of the 1-alkyl-3-methylimidazolium cation and has been supported by a
1-烷基-3-甲基咪唑鎓阳离子类离子液体有效地催化ñ -叔胺的-butyloxycarbonylation具有优良的化学选择性。所述离子液体的催化作用是设想为二的“亲电活化”叔丁基酯(BOC 2 O)通过分叉氢键的形成与1-烷基-3-甲基咪唑鎓阳离子的和C-2的氢已由咪唑C-2氢1-丁基-3-甲基咪唑鎓双(三氟甲基磺酰)亚胺([BMIM] [NTF的的低磁场移位支撑2从δ8.39]),以8.66的中的Boc存在2于O 11 H NMR和无C-2氢的1-丁基-2,3-二甲基咪唑鎓离子液体的催化效率急剧降低。与芳族和脂族胺反应所需的不同时间为分子间和分子内竞争期间选择性形成N - t- Boc提供了手段。在伯脂族胺的存在下,已经与仲脂族胺形成了优选的N - t- Boc。比较N - t -Boc与常见底物的催化效率,发现[bmim] [NTf 2 ]优于已报道的路易斯酸催化剂。
Convenient synthesis of protected primary amines from nitriles
作者:Stephen Caddick、Alexandra K de K. Haynes、Duncan B Judd、Meredith R.V Williams
DOI:10.1016/s0040-4039(00)00410-x
日期:2000.4
Investigations into the use of nickel chloride and sodiumborohydride for the reduction of nitriles showed the secondary amine dimers to be the major products under normal conditions. The addition of a suitable trapping agent, such as di-tert-butyl dicarbonate, allowed the isolation of the protected primaryamines.
Selective Fmoc and Cbz protection of aromatic amino group in the presence of similar aliphatic function in liquid CO2
作者:Dmitry A. Guk、Roman O. Burlutskiy、Dmitriy A. Lemenovskiy、Elena K. Beloglazkina
DOI:10.1016/j.mencom.2023.01.004
日期:2023.1
The selective protection of an aromaticaminogroup in the presence of aliphatic aminogroup in diamines by the action of FmocCl or CbzCl using liquid CO2 as the solvent has been proposed. The developed method is preparative, does not require complex purification of the product, and meets the principles of green chemistry.
Selective nitrolytic deprotection of N -BOC-amines and N -BOC-amino acids derivatives
作者:Paolo Strazzolini、Tiziana Melloni、Angelo G Giumanini
DOI:10.1016/s0040-4020(01)00900-0
日期:2001.10
configuration of the substrates and without affecting copresent Z and ester functions, with a remarkable selectivity towards acid sensitive t-butylesters. The obtained aminoacidsesters, isolated and characterized in the form of nitrates salts, proved to be suitable intermediates to be used in peptide synthesis.
A generic approach for the catalytic reduction of nitriles
作者:Stephen Caddick、Duncan B Judd、Alexandra K.de K Lewis、Melanie T Reich、Meredith R.V Williams
DOI:10.1016/s0040-4020(03)00858-5
日期:2003.7
The scope of nickel boride mediated reduction of nitriles has been extended further to allow the preparation of Boc protected amines via a mild catalytic process. It is noteworthy that the toxicity of this procedure is greatly reduced due to its catalytic nature in nickel(II) chloride used in combination with excess sodium borohydride. The protocol is marked by its resilience towards air and moisture