127119-07-7Relevant academic research and scientific papers
General solvent-free highly selective N-tert-butyloxycarbonylation strategy using protic ionic liquid as an efficient catalyst
Majumdar, Swapan,De, Jhinuk,Chakraborty, Ankita,Maiti, Dilip K.
, p. 24544 - 24550 (2014)
A simple, rapid and solvent-free protocol is described for the chemo-selective transformation of amines to tert-butyloxycarbonyl protected derivatives (NHBoc) using Boc2O and imidazolium trifluoroacetate protic ionic liquid (5-20 mol%). Unwanted side products such as isocyanate, urea or N,N-di-Boc were not detected. The scope of the protection strategy was successfully explored for substrate alcohols, phenols and thiol at elevated temperatures. Optically pure amino acids, amino acid esters and amino alcohols were efficiently converted to the corresponding N-Boc protected derivatives in excellent yields without racemization at the chiral center. The distinct advantages of this method are: operational simplicity, cleaner reaction, high selectivity, excellent yield, rapid reaction convergence, easy preparation and recyclability of the catalyst.
An entry to 2-(cyclobut-1-en-1-yl)-1: H -indoles through a cyclobutenylation/deprotection cascade
Natho, Philipp,Yang, Zeyu,Allen, Lewis A. T.,Rey, Juliette,White, Andrew J. P.,Parsons, Philip J.
, p. 4048 - 4053 (2021)
A transition-metal-free strategy for the synthesis of 2-(cyclobut-1-en-1-yl)-1H-indoles under mild conditions is described herein. A series of substituted 2-(cyclobut-1-en-1-yl)-1H-indoles are accessed by a one-pot cyclobutenylation/deprotection cascade from N-Boc protected indoles. Preliminary experimental and density functional theory calculations suggest that a Boc-group transfer is involved in the underlying mechanism.
Visible-light-induced aerobic oxidative desulfurization of 2-mercaptobenzimidazolesviaa sulfinyl radical
Deng, Guo-Jun,Fu, Mei,Huang, Huawen,Ji, Xiaochen,Li, Yongtong
supporting information, p. 5594 - 5598 (2020/09/21)
A mild transition-metal-free non-toxic aerobic photoredox system was found to enable highly efficient desulfurization of 2-mercaptobenzimidazoles. This viable catalytic system includes Rose Bengal in a low catalyst loading as a photosensitizer and cheap, non-toxic NaCl in a catalytic amount as an additive, combined with an oxygen atmosphere. This protocol provides an important alternative access to a broad range of benzimidazole and deuterated benzimidazole products in generally high yields with good tolerance of various synthetically and pharmaceutically useful functionalities. The mechanistic studies reveal that both single electron transfer and energy transfer probably occur in the initial step and a sulfinyl radical intermediate is involved in the key desulfurization process.
Derisking the Cu-Mediated 18F-Fluorination of Heterocyclic Positron Emission Tomography Radioligands
Taylor, Nicholas J.,Emer, Enrico,Preshlock, Sean,Schedler, Michael,Tredwell, Matthew,Verhoog, Stefan,Mercier, Joel,Genicot, Christophe,Gouverneur, Véronique
supporting information, p. 8267 - 8276 (2017/06/27)
Molecules labeled with fluorine-18 (18F) are used in positron emission tomography to visualize, characterize and measure biological processes in the body. Despite recent advances in the incorporation of 18F onto arenes, the development of general and efficient approaches to label radioligands necessary for drug discovery programs remains a significant task. This full account describes a derisking approach toward the radiosynthesis of heterocyclic positron emission tomography (PET) radioligands using the copper-mediated 18F-fluorination of aryl boron reagents with 18F-fluoride as a model reaction. This approach is based on a study examining how the presence of heterocycles commonly used in drug development affects the efficiency of 18F-fluorination for a representative aryl boron reagent, and on the labeling of more than 50 (hetero)aryl boronic esters. This set of data allows for the application of this derisking strategy to the successful radiosynthesis of seven structurally complex pharmaceutically relevant heterocycle-containing molecules.
Copper nanoparticles catalyzed N-H functionalization: An efficient solvent-free N-tert-butyloxycarbonylation strategy
Deb, Barnali,Debnath, Sudipto,Deb, Anindita,Maiti, Dilip K.,Majumdar, Swapan
supporting information, p. 629 - 633 (2017/01/25)
A chemoselective transformation of amines to their tert-butyloxycarbonyl (Boc) protected derivatives (NBoc) is described using Cu-NPs under solvent-free conditions. Simple method, rapid reaction rate, mild conditions, tolerance of a wide range of functional groups, excellent yield, ease recovery and high catalytic turnover are the salient features of this approach. tert-Butyloxycarbonylation of chiral amino acid esters and amino alcohols were performed without racemization.
Selective C-H trifluoromethylation of benzimidazoles through photoredox catalysis
Gao, Guo-Lin,Yang, Chao,Xia, Wujiong
supporting information, p. 1041 - 1044 (2017/02/05)
The protocol presented here is a new strategy for visible light induced C-H trifluoromethylation at C4 of benzimidazoles using Togni's reagent in the presence of fac-Ir(ppy)3. Its advantages are its operational simplicity, mild reaction conditions, low catalyst loading and wide substrate scope in which electron-withdrawing, electron-donating groups and different protecting groups are tolerated.
RADIATION-SENSITIVE RESIN COMPOSITION, METHOD FOR FORMING A RESIST PATTERN, COMPOUND, AND POLYMER
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, (2012/06/30)
A radiation-sensitive resin composition includes a first polymer that includes a repeating unit having an acid-labile group and becomes alkali-soluble upon dissociation of the acid-labile group, and a radiation-sensitive acid-generating agent. The acid-labile group has a structure shown by a general formula (1). R1 represents a methyl group or the like, R2 represents a hydrocarbon group that forms a cyclic structure, R3 represents a fluorine atom or the like, R4 represents a carbon atom, and n1 is an integer from 1 to 7.
An efficient and chemoselective Br?nsted acidic ionic liquid-catalyzed N-Boc protection of amines
Sunitha, Sadula,Kanjilal, Sanjit,Reddy, P. Srinivasa,Prasad, Rachapudi B.N.
, p. 2527 - 2532 (2008/09/19)
The first report of a Br?nsted acidic ionic liquid, 1-methylimidazolium tetrafluoroborate [(HMIm)BF4], catalyzed efficient and chemoselective N-Boc protection of various amines using (Boc)2O is presented. Optically pure amino alcohols and amino acid esters were converted efficiently to their corresponding optically pure N-Boc derivatives. The reported method is mild, solvent-free and has the advantages of both homogeneous and heterogeneous catalysis with high product yields, selectivity and ease of product separation.
A highly chemoselective Boc protection of amines using sulfonic-acid-functionalized silica as an efficient heterogeneous recyclable catalyst
Das, Biswanath,Venkateswarlu, Katta,Krishnaiah, Maddeboina,Holla, Harish
, p. 7551 - 7556 (2008/02/08)
A facile and versatile method for the chemoselective Boc protection of amines has been developed by a treatment with (Boc)2O in the presence of sulfonic-acid-functionalized silica as a catalyst. The method is general for the preparation of N-Boc derivatives of aliphatic (acyclic and cyclic), aromatic, and heteroaromatic amines; primary and secondary amines; aminols, amino-esters; and sulfonamides. The catalyst works under heterogeneous conditions and can be recycled.
SELECTIVE REMOVAL OF THE TERT-BUTOXYCARBONYL GROUP FROM SECONDARY AMINES: ZnBr2 AS THE DEPROTECTING REAGENT
Nigam, Satish C.,Mann, Andre,Taddei, Maurizio,Wermuth, Camille-Georges
, p. 3139 - 3142 (2007/10/02)
ZnBr2 in dichloromethane is a convenient reagent for mild and selective removal of the tert-butoxycarbonyl group from secondary amines.
