A Simple and Efficient Green Method for the Deprotection of N-Boc in Various Structurally Diverse Amines under Water-mediated Catalyst-free Conditions (original) (raw)
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Simultaneous Deprotection and Purification of BOC-amines Based on Ionic Resin Capture
The Journal of Organic Chemistry, 1998
Combinatorial chemistry and the synthesis of chemical libraries has resulted in a need to develop new strategies to rapidly and simply purify, isolate, and manipulate library members during each synthetic step. Two major strategies have been used. The first uses cross-linked polymers such as those used in Merrifield's solid-phase peptide synthesis. 1,2 The second strategy uses soluble polymer supports or biphasic syntheses. 3,4 The recent development of polymer-supported quenching reagents as a rapid purification tool in solution-phase parallel synthesis is an outgrowth of the former strategy. 5 This chemistry typically relies on molecular reactivity and/or molecular recognition (often acid-base chemistry) as the means by which excess reagents or byproducts are sequestered and isolated. On the other hand, the "resin capture" idea has also recently been introduced as an alternative solution-phase library methodology. 6 This method uses functionalized resins to trap selectively (via a covalent bond linkage) the desired products away from solution-phase reagents or byproducts. The products are then released from the resin through an appropriate cleavage step. Herein, we disclose a new and simple ionic equivalent of this resin capture technique as demonstrated by the deprotection and purification of solutionphase BOC-protected amines through the use of a strongly acidic macroreticular ion-exchange resin, Amberlyst 15.
Novel Practical Deprotection of N-Boc Compounds Using Fluorinated Alcohols
Synthetic Communications, 2008
The thermolytic deprotection of N-Boc compounds was accomplished using TFE (2,2,2-trifluoroethanol) or HFIP (hexafluoroisopropanol) as solvents. Even though the cleavage of the t-butylcarbamate (Boc) group can be achieved at solvent reflux temperature, the deprotection process was significantly accelerated under microwave-assisted conditions. The practicality of this methodology was demonstrated on alkyl, aryl, and heteroaromatic N-Boc-amines.
A mild and selective method for N-Boc deprotection
Tetrahedron Letters, 2002
A new mild method to remove N-tert-butyloxycarbonyl groups using TBAF in refluxing THF is reported. In all cases, the corresponding N-free products are obtained in good yields. The reactions are selective for acid-and base-sensitive groups, such as tert-butyl and alkyl esters, aldehydes.
International Journal of Scientific Research in Science and Technology, 2020
The protecting group plays important role in synthesis of multifunctional targets. A simple rapid efficient and green method for chemo-selective N-Boc protection of amines using Lithium hydroxide as a green catalyst. In the present work amine protection in presence of ditert-butyl carbonate under solvent free condition is carried out. An efficient green protocol for chemoselctive N-Boc protection of aryl, aliphatic, aromatic, acyclic and hetero cyclic amines (1 m mol %)( 10, 20, 30) were carried out with ditert-butyl carbonate (Boc)2 O using Lithium hydroxide monohydrate (10 mol %) at room temperature under solvent free condition to give white solid monitored on TLC. No side reactions are observed .The present protocol were simple, rapid, efficient, shorter reaction times, high yielding, highly selective, economical and eco-friendly
Journal of the Chilean Chemical Society, 2013
An efficient, environmentally benign, highly facile and convenient synthetic protocol for the selective t-butyl carboxylation of aliphatic, aromatic and heterocyclic amines using Amberlyst R A 21 catalyst; a mild basic solid resin under solvent free conditions is reported. This method explores several advantages such as reusability of the heterogeneous catalyst, cleaner reaction profile, mild and solvent free system, short reaction time, operational simplicity, high conversions , excellent product yields and low cost of the catalyst. Furthermore since the catalyst is mild basic, decomposition of the carbamate formed is not observed if the reaction is continued for prolonged time as in the case of Lewis acid catalyzed N-Boc protection. This makes the present protocol a useful and attractive for N-Boc protection of amines.
Solvent-Free Mechanochemical Deprotection of N-Boc Group
International Journal of Organic Chemistry, 2017
Boc protection group could be readily removed in a very mild mechanochemical conditions. In a short reaction time, ball milling of Boc-protected amines with p-toluenesulfonic acid in solvent-free conditions affords corresponding amine p-TsOH salts.