- Sulfated tungstate: A highly efficient, recyclable and ecofriendly catalyst for chemoselective N-tert butyloxycarbonylation of amines under the solvent-free conditions
-
Sulfated tungstate catalyzed an efficient and ecofriendly protocol has been described for the chemoselective N-tert-butyloxycarbonylation of amines under the solvent-free conditions at room temperature. The variety of functionalized aliphatic, aromatic and heteroaromatic amines efficiently undergoes the N-tert-butyloxycarbonylation under the developed protocol. The aminoalcohol, aminophenol, aminoester as well as various chiral amines underwent the chemoselective N-Boc protection under the optimized reaction condition. The rapid reaction rate, mild conditions, very good functional group tolerance, excellent yield, solvent-free, easy recovery products and excellent catalyst recyclability are the advantages of this protocol. This makes the protocol feasible, economical and environmentally benign.
- Ingale, Ajit P.,Shinde, Sandeep V.,Thorat, Nitin M.
-
supporting information
p. 2528 - 2543
(2021/07/02)
-
- Ultrasound promoted environmentally benign, highly efficient, and chemoselective N-tert-butyloxycarbonylation of amines by reusable sulfated polyborate
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The sulfated polyborate catalyzed an efficient and chemoselective N-tert-butyloxycarbonylation of amines under ultrasonic irradiation is developed. A broad substrate scope has been demonstrated for N-Boc protection of various primary/secondary amines. It allows converting several aliphatic/aryl/heteroaryl amines, amino alcohol, aminoester, and chiral amines to their N-Boc-protected derivatives under solvent-free conditions with excellent yields. The protocol has several advantages such as easy catalyst, and product isolation, short reaction time, excellent yields, outstanding chemoselectivity, and catalyst recyclability, among others. This makes the process practicable, economical, and environmentally benign.
- Pise, Ashok S.,Ingale, Ajit P.,Dalvi, Navnath R.
-
supporting information
p. 3768 - 3780
(2021/10/26)
-
- Nanoceria as an efficient and green catalyst for the chemoselective N-tert-butyloxycarbonylation of amines under the solvent-free conditions
-
Nanocerium oxide mediated an efficient and green protocol has been described for the chemoselective N-tert-butyloxycarbonylation of amines under the solvent-free conditions at ambient temperature. Various aliphatic, aromatic and heteroaromatic amines were protected using developed protocol and several functional groups such as alcohol, phenol and ester were well tolerated under these conditions. The rapid reaction rate, mild conditions, very good functional group tolerance, excellent yield, solvent-free, easy recovery products and excellent catalyst recyclability are the advantages of this protocol. This makes the protocol feasible, economical and environmentally benign.
- Garad, Dnyaneshwar N.,Ingale, Ajit P.,Shinde, Sandeep V.,Ukale, Dattatraya
-
supporting information
p. 1656 - 1668
(2021/04/05)
-
- Thiamine hydrochloride as a recyclable organocatalyst for the efficient and chemoselective N-tert-butyloxycarbonylation of amines
-
Thiamin hydrochloride promoted highly efficient and ecofriendly approach has been described for the chemoselective N-tert-butyloxycarbonylation of amines under solvent-free conditions at ambient temperature. The demonstrated approach has been applicable for the N-Boc protection of variety of aliphatic, aryl, heteroaryl amines. The chemoselective protection of amino group occurs in chiral amines and amino alcohol without racemization in high yield. Thiamin hydrochloride is stable, economical, easy to handle and environmentally friendly.
- Ingale, Ajit P.,Garad, Dnyaneshwar N.,Ukale, Dattatraya,Thorat, Nitin M.,Shinde, Sandeep V.
-
supporting information
p. 3791 - 3804
(2021/11/04)
-
- Copper(ii)-hydroxide facilitated C-C bond formation: The carboxamido pyridine system: Versus the methylimino pyridine system
-
A copper(ii)-hydroxide-induced carbon-carbon bond formation reaction is explored with the synthesis of an asymmetric carboxamido-methylimino pyridine Cu(i) complex of [CuI(py(N-CO)(NC-C)ph2Me2)2]- (12). Two imine-methyl groups are coupled to form a bridge
- Fan, Weibin,Huang, Deguang,Li, Yinghua,Xiang, Shiqun,Xie, Xingkun,Zhang, Zilong
-
supporting information
p. 12189 - 12196
(2020/10/02)
-
- Synthesis method of telmisartan intermediate 4-amino-3-methylbenzoic acid
-
The invention discloses a synthesis method of telmisartan intermediate 4-amino-3-methylbenzoic acid. According to the synthesis method, 2-methylaniline reacts with chloroformate under the action of acatalyst to obtain the 4-amino-3-methylbenzoic acid. The synthesis method has the advantages of few reaction step, easy availability of raw materials, few side reaction, high reaction yield, high product purity, low process cost, simple post-treatment operation, no pollution and no emission.
- -
-
Paragraph 0030-0035; 0036; 0038; 0042-0055
(2019/05/21)
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- Chemoselective: N-tert -butyloxycarbonylation of amines in glycerol
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A catalyst-free, efficient and green protocol has been developed for the chemoselective N-Boc protection of amines by using glycerol as a solvent at room temperature. A variety of functionalized amines, such as aliphatic, aromatic as well as heteroaromatic were protected using the developed protocol. N-tert-Butyloxycarbonylation derivatives were formed without the formation of isocyanate, urea, N,N-di-t-Boc, or oxazolidinone as side products. The operational simplicity, cleaner reaction, rapid reaction convergence, functional group tolerance, excellent yield, high selectivity, catalyst-free feature and solvent recyclability are the distinct advantages of this protocol. Owing to these merits, this protocol is feasible, economical and environmentally benign.
- Ingale, Ajit P.,More, Vishal K.,Gangarde, Uddhav S.,Shinde, Sandeep V.
-
supporting information
p. 10142 - 10147
(2018/06/18)
-
- Synthesis, Reactivity, Functionalization, and ADMET Properties of Silicon-Containing Nitrogen Heterocycles
-
Silicon-containing compounds have been largely ignored in drug design and development, despite their potential to improve not only the potency but also the physicochemical and ADMET (absorption, distribution, metabolism, excretion, toxicity) properties of drug-like candidates because of the unique characteristics of silicon. This deficiency is in large part attributable to a lack of general methods for synthesizing diverse organosilicon structures. Accordingly, a new building block strategy has been developed that diverges from traditional approaches to incorporation of silicon into drug candidates. Flexible, multi-gram-scale syntheses of silicon-containing tetrahydroquinoline and tetrahydroisoquinoline building blocks are described, along with methods by which diversely functionalized silicon-containing nitrogen heterocycles can be rapidly built using common reactions optimized to accommodate the properties of silicon. Furthermore, to better clarify the liabilities and advantages of silicon incorporation, select compounds and their carbon analogues were challenged in ADMET-focused biological studies.
- Barraza, Scott J.,Denmark, Scott E.
-
supporting information
p. 6668 - 6684
(2018/06/12)
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- Base-Mediated Intramolecular Decarboxylative Synthesis of Alkylamines from Alkanoyloxycarbamates
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A general and effective method for the synthesis of alkylamine via intramolecular decarboxylation of alkanoyloxycarbamates is described. The alkanoyloxycarbamates are readily prepared with alkyl carboxylic acids and hydroxylamine. The reaction shows a broad range of substrates (primary and secondary alkyl) with functional tolerance, and the corresponding products were obtained in good yields under mild conditions.
- Li, Peihe,Ma, Nuannuan,Wang, Zheng,Dai, Qipu,Hu, Changwen
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p. 8233 - 8240
(2018/05/31)
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- Copper nanoparticles catalyzed N-H functionalization: An efficient solvent-free N-tert-butyloxycarbonylation strategy
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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.
- Deb, Barnali,Debnath, Sudipto,Deb, Anindita,Maiti, Dilip K.,Majumdar, Swapan
-
supporting information
p. 629 - 633
(2017/01/25)
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- Preparation, characterization and application of 1,4-disulfopiperazine-1,4-diium chloride ([Piper-(SO3H)2]·2Cl) as an efficient dicationic ionic catalyst for the N-Boc protection of amines
-
In this work, 1,4-disulfopiperazine-1,4-diium chloride ([Piper-(SO3H)2]·2Cl), as a novel Br?nsted acidic ionic catalyst is synthesized and characterized using a series of techniques including FT-IR, TGA, DTA, SEM, pH analysis and Hammett acidity function. This substance can significantly catalyze the N-Boc protection of amines without solvent interference at room temperature. The advantages of this manner are chemoselectivity, short reaction times, suitable yields, excellent yields of the products, without solvent interference and ease of preparation as well as reusability of the catalyst.
- Koodehi, Tahereh Ghauri,Shirini, Farhad,Goli-Jolodar, Omid
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p. 443 - 456
(2017/01/10)
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- [TPA][Pro] ionic liquid as efficient reaction medium for N-tert-Boc protection of amines
-
A facile and efficient N-tert-Boc protection of amines is described by the reaction of various primary, secondary, benzylic and aryl amines with di-tert-butyl dicarbonate in the ionic liquid [TPA][Pro] at room temperature. All the N-tert-butylcarbamates are afforded in excellent yields. A catalyst-free method was developed and the ionic liquid [TPA][Pro] can be recovered and reused for several times without loss of its activity.
- Vijaya Durga,Rambabu,Srinivasa Reddy,Hari Babu
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p. 1313 - 1316
(2017/05/02)
-
- Transposed Paternò-Büchi reaction
-
A complementary strategy of utilizing nπ? excited state of alkene instead of nππ? excited state of the carbonyl chromophore in a "transposed Paternò-Büchi" reaction is evaluated with atropisomeric enamides as the model system. Based on photophysical inves
- Kumarasamy, Elango,Raghunathan, Ramya,Kandappa, Sunil Kumar,Sreenithya,Jockusch, Steffen,Sunoj, Raghavan B.,Sivaguru
-
supporting information
p. 655 - 662
(2017/05/16)
-
- Ligand-Promoted Meta-C-H Arylation of Anilines, Phenols, and Heterocycles
-
Here we report the development of a versatile 3-acetylamino-2-hydroxypyridine class of ligands that promote meta-C-H arylation of anilines, heterocyclic aromatic amines, phenols, and 2-benzyl heterocycles using norbornene as a transient mediator. More than 120 examples are presented, demonstrating this ligand scaffold enables a wide substrate and coupling partner scope. Meta-C-H arylation with heterocyclic aryl iodides as coupling partners is also realized for the first time using this ligand. The utility for this transformation for drug discovery is showcased by allowing the meta-C-H arylation of a lenalidomide derivative. The first steps toward a silver-free protocol for this reaction are also demonstrated.
- Wang, Peng,Farmer, Marcus E.,Huo, Xing,Jain, Pankaj,Shen, Peng-Xiang,Ishoey, Mette,Bradner, James E.,Wisniewski, Steven R.,Eastgate, Martin D.,Yu, Jin-Quan
-
supporting information
p. 9269 - 9276
(2016/08/05)
-
- Palladium-Catalyzed Decarboxylative Synthesis of Arylamines
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A novel approach has been developed for the synthesis of arylamines via the palladium-catalyzed intramolecular decarboxylative coupling (IDC) of aroyloxycarbamates, obtained in situ by reacting aryl carboxylic acids with hydroxycarbamates. The reaction offers facile access to structurally diverse arylamines with the site-specific formation of the C(sp2)-N bond under mild conditions.
- Dai, Qipu,Li, Peihe,Ma, Nuannuan,Hu, Changwen
-
supporting information
p. 5560 - 5563
(2016/11/17)
-
- Preparation, characterization and application of succinimidinium hydrogensulfate ([H-Suc]HSO4) as an efficient ionic liquid catalyst for the N-Boc protection of amines
-
In this work, succinimidinium hydrogensulfate ([H-Suc]HSO4), as a novel Bronsted acidic ionic liquid is prepared and characterized by studying its FT-IR, 1H NMR, 13C NMR, mass and SEM. This reagent can be used as an efficient catalyst for the N-Boc protection of amines at room temperature and neat conditions. This new method consistently has the advantages of excellent yields and short reaction times. Further, this ionic liquid can be recovered and reused for several times. This journal is
- Shirini, Farhad,Jolodar, Omid Goli,Seddighi, Mohadeseh,Borujeni, Hojatollah Takbiri
-
p. 19790 - 19798
(2015/03/18)
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- Installation of protected ammonia equivalents onto aromatic & heteroaromatic rings in water enabled by micellar catalysis
-
A single set of conditions consisting of a palladium catalyst, a commercially available ligand, and a base, allow for several types of C-N bond constructions to be conducted in water with the aid of a commercially available "designer" surfactant (TPGS-750-M). Products containing a protected NH2 group in the form of a carbamate, sulfonamide, or urea can be fashioned starting with aryl or heteroaryl bromides, iodides, and in some cases, chlorides, as substrates. Reaction temperatures are in the range of room temperature to, at most, 50 °C, and result in essentially full conversion and good isolated yields.
- Isley, Nicholas A.,Dobarco, Sebastian,Lipshutz, Bruce H.
-
supporting information
p. 1480 - 1488
(2014/03/21)
-
- General solvent-free highly selective N-tert-butyloxycarbonylation strategy using protic ionic liquid as an efficient catalyst
-
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.
- Majumdar, Swapan,De, Jhinuk,Chakraborty, Ankita,Maiti, Dilip K.
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p. 24544 - 24550
(2014/07/07)
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- Synthesis of (S)- and (R)-harmicine from proline: An approach toward tetrahydro-β-carbolines
-
(S)- and (R)-Harmicine were synthesized from L- and D-proline, respectively. This chiral pool synthesis constitutes a new approach towards C1 substituted tetrahydro-β-carbolines. The developed route makes use of the 9-phenyl-9-fluorenyl protecting group strategy of amino acids to prevent racemization of the vulnerable α-amino carbonyl stereocenter. Enantiopure harmicine (> 99%ee) was obtained in nine steps from commercially available starting material. The synthesis was performed without the use of any silica gel flash chromatography.
- Lood, Christopher S.,Koskinen, Ari M. P.
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p. 2357 - 2364
(2014/04/17)
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- Nanocrystalline titania-based sulfonic acid (TiO2-Pr-SO 3H) as a new, highly efficient and recyclable solid acid catalyst for the N-Boc protection of amines at room temperature
-
Sulfonic acid-functionalized nanoporous titania (TiO2-Pr-SO 3H) was prepared from the reaction of (3-mercaptopropyl) trimethoxysilane and TiO2, then by oxidation of thiols group with hydrogen peroxide. The morphology and acidity of synthesized catalyst was characterized by FT-IR, SEM, TEM, TGA and XRD techniques and Hammett acidity test. The catalytic performance of TiO2-Pr-SO3H was investigated in the N-tert-butoxycarbonylation of amines under solvent-free conditions at room temperature. Our novel method is mild, chemoselective and has the advantages such as heterogeneous catalysis, low cost and the recyclability of the catalyst.
- Atghia,Sarvi Beigbaghlou
-
-
- {[[K.18-Crown-6]Br3}n: A tribromide catalyst for the catalytic protection of amines and alcohols
-
{[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 from the product is one of the many advantages of this method.
- Chehardoli, Gholamabbas,Zolfigol, Mohammad Ali,Derakhshanpanah, Fateme
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p. 1730 - 1733
(2013/10/21)
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- Synthesis, characterization and catalytic properties of monodispersed nano-sphere silica sulfuric acid
-
In this research, the first report on synthesis of nano-sphere silica sulfuric acid (NS-SSA) as new catalyst was reported. The catalyst was prepared by the reaction of nano-sphere silica with chlorosulfonic acid at room temperature. The catalyst has been identified using various techniques (XRD, SEM, TEM, EDX, TGA, FT-IR) and results were shown that it was a spherical shape and its particle size was between 60 and 90 nm. The catalyst can be easily recovered and reused for seventeen reaction cycles for protection of amines without considerable loss of activity. It was found that the catalyst can be efficiently in large scale and we examined some reactions in scales of 50 and 100 mmol. Also, this method has some advantages such as high TOF of catalyst, chemoselectivity, easy work-up and short reaction time.
- Zolfigol,Khazaei,Mokhlesi,Derakhshan-Panah
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p. 111 - 116
(2013/04/23)
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- Nano-ferrous ferric oxide (nano-Fe3O4): Powerful, reusable, and stable catalyst for N-Boc protection of amines
-
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.
- Zolfigol, Mohammad Ali,Moosavi-Zare, Ahmad Reza,Moosavi, Parvin,Khakyzadeh, Vahid,Zare, Abdolkarim
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p. 962 - 966
(2013/11/06)
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- Microwave assisted mild, rapid, solvent-less, and catalyst-free chemoselective N-tert-butyloxycarbonylation of amines
-
Microwave assisted simple, rapid, solventless, and catalyst-free chemoselective method for the protection of amino group in aromatic, aliphatic, heterocyclic, aralkyl amines, phenyl hydrazine, and amino acid esters in good to excellent isolated yield (83-98%) in short reaction time (2-12 min) has been reported.
- Dighe, Satish N.,Jadhav, Hemant R.
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p. 5803 - 5806
(2012/10/29)
-
- Cyclization-carbonylation-cyclization coupling reactions of N-propargylanilines and o-alkynylphenols with palladium(II)-bisoxazoline catalysts
-
Cyclization-carbonylation-cyclization coupling reactions (CCC-coupling reactions) of N-propargylanilines and o-alkynylphenols catalyzed by (box)Pd(II) complexes afforded symmetrical bis(quinolin-3-yl) and bis(benzofuran-3-yl) ketones, respectively, in mod
- Kusakabe, Taichi,Sekiyama, Emika,Ishino, Yukari,Motodate, Satoshi,Kato, Shigeki,Mochida, Tomoyuki,Kato, Keisuke
-
supporting information; experimental part
p. 1825 - 1832
(2012/07/30)
-
- Sulfonic acid-functionalized ordered nanoporous Na+- montmorillonite (SANM): A novel, efficient and recyclable catalyst for the chemoselective N-Boc protection of amines in solventless media
-
Sulfonic acid-functionalized ordered nanoporous Na+- montmorillonite (SANM) was used as an efficient catalyst for N-tert-butoxycarbonylation of amines with di-tert-butyl dicarbonate under solvent-free conditions at room temperature. Various aliphatic, aromatic, heterocyclic amines and aminols were protected as their corresponding mono-carbamates in excellent yields and short reaction times. No competitive side reactions such as isocyanate, urea, and N,N-di-Boc formation were observed. The reported method is mild, chemoselective and has the advantages such as heterogeneous catalysis, low cost and the recyclability of the catalyst.
- Shirini, Farhad,Mamaghani, Manouchehr,Atghia, Seyyed Vahid
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experimental part
p. 1088 - 1094
(2012/01/15)
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- Synthesis and crystal structure determination of [H2-cryptand 222](Br3)2: A unique tribromide catalyst for the catalytic chemoselective N-boc protection of amines
-
The organic tribromide, [H2-cryptand 222](Br3) 2 was synthesized and characterized by X-ray crystallography, and was utilized as an active catalyst for the N-boc protection of amines. The method is general for the preparation of N-boc derivatives of aliphatic (acyclic and cyclic), aromatic, primary and secondary amines. We also applied our new reaction protocols for the N-boc protection of some new amines and spectral and physical data for the obtained products are reported.
- Chehardoli, Gholamabbas,Zolfigol, Mohammad Ali,Khakyzadeh, Vahid,Golbedaghi, Reza,Hall, Nikita A.,Blackman, Allan G.
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experimental part
p. 538 - 543
(2012/01/03)
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- Pd-catalyzed amidation of aryl(Het) halides with tert-butyl carbamate
-
Pd-catalyzed cross-coupling reaction of tert-butyl carbamate with various aryl(Het) halides with Cs2CO3 as base in 1,4-dioxane as solvent was investigated, which resulted in the formation of the desired compounds in moderate to excellent yields.
- Qin, Lijin,Cui, Hongmeng,Zou, Dapeng,Li, Jingya,Wu, Yangjie,Zhu, Zhiwu,Wu, Yusheng
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experimental part
p. 4445 - 4448
(2010/09/12)
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- An expeditious, efficient green methodology for the Boc protection of amines and silyl protection of alcohols over tungstophosphoric acid-doped mesoporous silica
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An efficient, chemoselective and eco-friendly protocol for the protection of amines as N-tert-butylcarbamate using (Boc)2O and protection of alcohols as silyl ether using HMDS over tungstophosphoric acid/SBA15 has been developed. Solventless condition, easy work-up, short reaction time, excellent yields and reusability of the catalyst are the striking features of this methodology which can be considered to be one of the better methods for the protection of amines and alcohols.
- Karmakar, Bikash,Banerji, Julie
-
experimental part
p. 3855 - 3858
(2010/08/20)
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- Rhenium complexes with 2-(diphenylphosphinomethyl)aniline: Formation of a cyclic, trinuclear oxorhenium(V) core
-
Reactions of 2-(diphenylphosphinomethyl)aniline, H2L 2, with (NBu4)[ReOCl4] yield different oxo rhenium(V) complexes depending on the conditions applied. This comprises monomeric compounds such as [ReOCl3/
- Schroer, Jennifer,Wagner, Stefan,Abram, Ulrich
-
scheme or table
p. 10694 - 10701
(2011/02/18)
-
- Copper(II) tetrafluoroborate as a novel and highly efficient catalyst for N-tert-butoxycarbonylation of amines under solvent-free conditions at room temperature
-
Commercially available copper(II) tetrafluoroborate hydrate was found to be a highly efficient catalyst for chemoselective N-tert-butoxycarbonylation of amines with di-tert-butyl dicarbonate under solvent-free conditions and at room temperature. Various aromatic amines were protected as their N-tert-butyl carbamates in high yields and in short times. No competitive side reactions such as isocyanate, urea, and N,N-di-t-Boc formation was observed. Chemoselective N-tert-butoxycarbonylation was achieved with substrates bearing OH and SH groups. Chiral α-amino acid esters afforded the corresponding N-t-Boc derivatives in excellent yields.
- Chankeshwara, Sunay V.,Chakraborti, Asit K.
-
p. 1087 - 1091
(2007/10/03)
-
- Facile N-tert-butoxycarbonylation of amines using La(NO3)3·6H2O as a mild and efficient catalyst under solvent-free conditions
-
Facile N-tert-butoxycarbonylation of amines is described by the treatment of various primary, secondary, benzylic and aryl amines with di-tert-butyl dicarbonate in the presence of catalytic amounts of La(NO3)3·6H2O under solvent-free conditions at room temperature to afford N-tert-butylcarbamates in excellent yields.
- Suryakiran,Prabhakar,Reddy, T. Srikanth,Rajesh,Venkateswarlu
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p. 8039 - 8042
(2007/10/03)
-
- Catalyst-free chemoselective N-tert-butyloxycarbonylation of amines in water
-
Catalyst-free N-tert-butyloxycarbonylation of amines in water is reported. The N-t-Boc derivatives were formed chemoselectively without any isocyanate, urea, N,N-di-t-Boc, and O/S-t-Boc as side products. Chiral amines, esters of α-amino acids, and β-amino alcohol afforded optically pure N-t-Boc derivatives. Amino alcohol and 2-aminophenol afforded the N-t-Boc derivative without oxazolidinone formation. Selectivity was observed during competition of aromatic amine vs aliphatic amine, amine vs amino acid ester, amine vs amino alcohol, and primary amine vs secondary amine.
- Chankeshwara, Sunay V.,Chakraborti, Asit K.
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p. 3259 - 3262
(2007/10/03)
-
- Ultrasound promoted 'one pot' conversion of nitrocompounds to carbamates
-
An efficient ultrasound promoted novel direct conversion of nitro compounds to N-(tert-butoxycarbonyl) amines and N-(ethoxycarbonylamines) is achieved using Sn-NH4Cl for the first time.
- Chandrasekhar,Narsihmulu,Jagadeshwar
-
p. 771 - 772
(2007/10/03)
-
- Novel functionalized titanium(IV) benzylidenes for the traceless solid-phase synthesis of indoles
-
(matrix presented) Titanium(IV) benzylidenes bearing a masked nitrogen nucleophile in the ortho position converted Merrifield resin-bound esters into enol ethers. An unusual nitrogen protecting group, N-silylated tert-butyl carbamate, was employed. One percent TFA released N-Boc indoles in high yield and purity. N-Methyl indoles were also prepared. Cyclative termination was not required to release the chameleon catch. The first example of a carbonyl group within a titanium alkylidene reagent is reported.
- Macleod, Calum,Hartley, Richard C.,Hamprecht, Dieter W.
-
-
- Room-temperature palladium-catalyzed amination of aryl bromides and chlorides and extended scope of aromatic C-N bond formation with a commercial ligand
-
The reactions of aryl bromides with amines occurs at room temperature when using Pd(0) and P(t-Bu)3 in a 1:1 ratio, and the reactions of aryl chlorides occur at room temperature or 70 °C. The arylation of indoles and the new arylation of carbamates also occur when using P(t-Bu)3 as ligand.
- Hartwig, John F.,Kawatsura, Motoi,Hauck, Sheila I.,Shaughnessy, Kevin H.,Alcazar-Roman, Luis M.
-
p. 5575 - 5580
(2007/10/03)
-