- Design, synthesis and SAR of antitubercular benzylpiperazine ureas
-
Abstract: N-furfuryl piperazine ureas disclosed by scientists at GSK Tres Cantos were chosen as antimycobacterial hits from a phenotypic whole-cell screen. Bioisosteric replacement of the furan ring in the GSK Tres Cantos molecules with a phenyl ring led to molecule (I) with an MIC of 1?μM against Mtb H37Rv, low cellular toxicity (HepG2 IC50 ~ 80?μM), good DMPK properties and specificity for Mtb. With the aim of delineating the SAR associated with (I), fifty-five analogs were synthesized and screened against Mtb. The SAR suggests that the piperazine ring, benzyl urea and piperonyl moieties are essential signatures of this series. Active compounds in this series are metabolically stable, have low cellular toxicity and are valuable leads for optimization. Molecular docking suggests these molecules occupy the Q0 site of QcrB like Q203. Graphic Abstract: Bioisosteric replacement of N-furfuryl piperazine-1-carboxamides yielded molecule (I) a novel lead with satisfactory PD, metabolism, and toxicity profiles.[Figure not available: see fulltext.]
- Satish, Sohal,Chitral, Rohan,Kori, Amitkumar,Sharma, Basantkumar,Puttur, Jayashree,Khan, Afreen A.,Desle, Deepali,Raikuvar, Kavita,Korkegian, Aaron,Martis, Elvis A. F.,Iyer, Krishna R.,Coutinho, Evans C.,Parish, Tanya,Nandan, Santosh
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- Copper-Catalyzed Coupling of Amines with Carbazates: An Approach to Carbamates
-
A new approach for the preparation of carbamatesviathe copper-catalyzed cross-coupling reaction of amines with alkoxycarbonyl radicals generated from carbazates is described. This environmentally friendly protocol takes place under mild conditions and is compatible with a wide range of amines, including aromatic/aliphatic and primary/secondary substrates.
- Wang, Song-Ning,Zhang, Guo-Yu,Shoberu, Adedamola,Zou, Jian-Ping
-
p. 9067 - 9075
(2021/07/19)
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- Interrupted aza-Wittig reactions using iminophosphoranes to synthesize 11C-carbonyls
-
A direct CO2-fixation methodology couples structurally diverse iminophosphoranes with various nucleophiles to synthesize ureas, carbamates, thiocarbamates, and amides, and is amenable for 11C radiolabeling. This methodology is practical, as demonstrated by the synthesis of >35 products and isolation of the molecular imaging radiopharmaceuticals [11C]URB694 and [11C]glibenclamide. This journal is
- Ismailani, Uzair S.,Munch, Maxime,Mair, Braeden A.,Rotstein, Benjamin H.
-
supporting information
p. 5266 - 5269
(2021/06/06)
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- Metal-free late-stage C(sp2)-H functionalization of: N -aryl amines with various sodium salts
-
Metal-free consecutive C(sp2)-X (X = Cl, Br, S, N) bond formations of N-aryl amines (cyclic, fused, carbamate, and aminium radicals) were achieved under mild conditions using [bis(trifluoroacetoxy)iodo]benzene (PIFA) and simple nonharmful sodium salts. This direct and selective C(sp2)-H functionalization showed excellent functional group compatibility, cost effectiveness, and late-stage applicability for the synthesis of biologically active natural products. Two mechanisms were proposed to explain the ortho- or para-preference, as well as the accelerating effect of CH3NO2
- Mudithanapelli, Chandrashekar,Kim, Mi-Hyun
-
p. 450 - 464
(2020/02/03)
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- Nickel-Catalyzed Synthesis of N-(Hetero)aryl Carbamates from Cyanate Salts and Phenols Activated with Cyanuric Chloride
-
A simple and efficient domino reaction has been designed and employed for the one-pot synthesis of N-(hetero)aryl carbamates through the reaction between alcohols and in-situ produced (hetero)aryl isocyanates in the presence of a nickel catalyst. The phenolic C?O bond was activated via the reaction of phenol with cyanuric chloride (2,4,6-trichloro-1,3,5-triazine (TCT)) as an inexpensive and readily available reagent. This strategy provides practical access to N-(hetero)aryl carbamates in good yields with high functional groups compatibility.
- Dindarloo Inaloo, Iman,Esmaeilpour, Mohsen,Majnooni, Sahar,Reza Oveisi, Ali
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p. 5486 - 5491
(2020/09/04)
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- Zn(ii)@TFP-DAQ COF: An efficient mesoporous catalyst for the synthesis of: N -methylated amine and carbamate through chemical fixation of CO2
-
Selective N-methylation and carbamate formation reactions were demonstrated via the chemical incorporation of CO2 using a Zn-loaded TFP-DAQ COF (covalent organic framework) as an active catalyst under mild reaction conditions. The selective N-methylation and N-formylation reactions were performed by simply varying the type of solvent. The Zn(ii)@TFP-DAQ COF catalyst was characterized via different characterization techniques such as PXRD, FTIR, UV-vis, N2 adsorption-desorption studies, FESEM and TEM. The catalyst material showed pores in the mesoporous region with a high surface area of 1117.375 m2 g-1. The as-synthesized material was applied as a cheap catalyst for the N-methylation of secondary amines and in carbamate formation reactions with high yields of the desired products up to 98.5% and 97%, respectively, with >99% selectivity. The catalyst was found to be completely heterogeneous and reusable for multiple reaction cycles.
- Sarkar, Priyanka,Chowdhury, Arpita Hazra,Riyajuddin, Sk.,Biswas, Surajit,Ghosh, Kaushik,Islam, Sk. Manirul
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p. 744 - 752
(2020/01/31)
-
- A General Copper-Catalyzed Synthesis of Ynamides from 1,2-Dichloroenamides
-
Ynamides are accessed via copper-catalyzed coupling of Grignard or organozinc nucleophiles with chloroynamides, formed in situ from 1,2-dichloroenamides. The reaction exhibits a broad substrate scope, is readily scaled, and overcomes typical limitations in ynamide synthesis such as the use of ureas, carbamates, and bulky or aromatic amide derivatives. This modular approach contrasts with previous routes by installing both the N- and C-substituents of the ynamide as nucleophilic components.
- Mansfield, Steven J.,Smith, Russell C.,Yong, Jonathan R. J.,Garry, Olivia L.,Anderson, Edward A.
-
supporting information
p. 2918 - 2922
(2019/04/25)
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- Carbon dioxide utilization in the efficient synthesis of carbamates by deep eutectic solvents (DES) as green and attractive solvent/catalyst systems
-
A green and eco-friendly solvent/catalyst system based on a deep eutectic solvent (DES) was devised and developed for the simple synthesis of carbamates through three-component coupling of amines, alkyl halides and carbon dioxide (CO2). It was found that choline chloride:zinc(ii) chloride ([ChCl][ZnCl2]2) was very proficient and effective for the activation and utilization of CO2 in carbamate formation reactions from a wide scope of amines. Surprisingly, this strategy provides the desired carbamates under atmospheric CO2 pressure at room temperature. In particular, both aromatic and aliphatic amines were effective and demonstrated excellent yields. Besides, the [ChCl][ZnCl2]2 exhibited very high stability and also could be reused for at least five consecutive cycles without any significant loss of activity. It is worth noting that this is the first solvent/catalyst system which can be recycled successfully from the reaction mixture.
- Dindarloo Inaloo, Iman,Majnooni, Sahar
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p. 11275 - 11281
(2019/07/31)
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- CaI2-Catalyzed direct transformation of: N -Alloc-, N -Troc-, and N -Cbz-protected amines to asymmetrical ureas
-
A novel and facile CaI2-catalyzed direct synthesis of asymmetrical ureas from N-Alloc-, N-Troc-, and N-Cbz-protected amines is developed. In this study, the efficient reaction of Alloc-, Troc-, and Cbz-carbamates with amines in the presence of catalytic CaI2 successfully generated various asymmetrical ureas. This catalytic synthetic procedure provided the desired ureas via reactions of these protected aromatic and aliphatic amines with various amines in high yields without side products. This suggests that novel direct synthesis of ureas from Alloc-, Troc-, and Cbz-carbamates can be a promising approach for the synthesis of useful ureas.
- Tran, Van Hieu,Kim, Hee-Kwon
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p. 14093 - 14101
(2019/09/18)
-
- Visible-Light-Promoted Oxo-Sulfonylation of Ynamides with Sulfonic Acids
-
A visible-light-promoted oxo-sulfonylation of ynamides with sulfonic acids is reported, giving rise to a collection of functionalized α-sulfonylated amides in a straightforward manner. The reaction proceeds sequentially through a cascade of electrophilic addition and photoinduced sulfonyl radical-sustained skeleton rearrangement. The high atom economy, mild reaction conditions, and wide substrate scope comprised the merits of this synthetic transformation.
- Wang, Lu,Lu, Chengrong,Yue, Yanni,Feng, Chao
-
supporting information
p. 3514 - 3517
(2019/05/16)
-
- A Fe3O4?SiO2/Schiff Base/Pd Complex as an Efficient Heterogeneous and Recyclable Nanocatalyst for One-Pot Domino Synthesis of Carbamates and Unsymmetrical Ureas
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A palladium-catalyzed domino method for the direct synthesis of carbamates and ureas has been developed by using readily available and economical starting materials (aryl halide, carbon monoxide, sodium azide, amines and alcohols) in a one-pot approach. The domino process underwent carbonylation, Curtius rearrangement, and nucleophilic addition. This protocol provides a step-economical and highly efficient reaction to access the wide range of valuable carbamates, symmetrical and unsymmetrical ureas with high yields under remarkable mild reaction conditions that are important factors in pharmaceutical science, biochemistry and agricultural industries. Furthermore, the magnetically recoverable nanocatalyst (Fe3O4?SiO2/Pd(II)) can be conveniently and swiftly recycled using external magnet and reused at least for seven times without noticeable loss of its catalytic activity.
- Inaloo, Iman Dindarloo,Majnooni, Sahar
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p. 6359 - 6368
(2019/11/05)
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- An Fe3O4@SiO2/Schiff base/Cu(ii) complex as an efficient recyclable magnetic nanocatalyst for selective mono: N-arylation of primary O-alkyl thiocarbamates and primary O-alkyl carbamates with aryl halides and arylboronic acids
-
An efficient, convenient and novel method for the selective mono N-arylation of primary O-alkyl thiocarbamates and primary O-alkyl carbamates with aryl halides and arylboronic acids in the presence of a recyclable magnetic Cu(ii) nanocatalyst is described. A variety of mono N-arylated O-alkyl thiocarbamates and O-alkyl carbamates were prepared in good to excellent yields with a broad range of aryl coupling partners. The magnetic nanocatalyst can be easily recovered with an external magnetic field and reused at least five times without noticeable leaching or loss of its catalytic activity. This cost-effective and eco-friendly methodology has some other advantages, such as easy preparation of the catalyst, simple workup procedure, and easy purification, which makes this protocol interesting for the users in various fields of pharmacology and biotechnology systems.
- Sardarian, Ali Reza,Dindarloo Inaloo, Iman,Zangiabadi, Milad
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p. 8557 - 8565
(2019/06/14)
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- One stone two birds: Cobalt-catalyzed in situ generation of isocyanates and benzyl alcohols for the synthesis of N-aryl carbamates
-
An efficient method for the synthesis of N-aryl carbamates from N-Boc-protected amines has been developed. The cobalt-catalyzed in situ generation of isocyanates from N-Boc-protected amines and benzyl alcohols from benzyl formates has been achieved for the first time, which in turn furnished the corresponding benzyl carbamates in moderate to high yields. The reaction was catalyzed by CoI2 with tris-(4-dimethylaminophenyl)-phosphine as the ligand and zinc powder as the reductant. The developed reaction conditions were found to be compatible for aromatic amines with both electron-donating and -withdrawing substituents.
- Li, Sida,Khan, Ruhima,Zhang, Xia,Yang, Yong,Wang, Zheting,Zhan, Yong,Dai, Yuze,Liu, Yue-E,Fan, Baomin
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p. 5891 - 5896
(2019/06/24)
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- Modified Graphene Oxide Based Zinc Composite: an Efficient Catalyst for N-formylation and Carbamate Formation Reactions Through CO2 Fixation
-
Catalytic fixation of CO2 through chemical reactions is always a challenging task of synthetic chemistry. This paper represents the design and synthesis of an eco-friendly low cost zinc metal containing heterogeneous catalyst of aminically modified Graphene Oxide. Characterization of the catalyst has been carried out by Raman and FTIR spectra, AAS, XRD, TEM, SEM, EDX and N2 adsorption desorption studies. It was found that the catalyst was very proficient for the CO2 fixation through N-formylation and carbamate formation reactions of amines. Catalytic N-formylation reaction of both aromatic and aliphatic amines gave high yield of corresponding formylated products in presence of polymethylhydrosiloxane (PMHS) as reducing agent under 1 bar CO2 pressure and mild temperature. Formation of carbamates from aniline or its derivatives and alkyl/aryl bromide with good product selectivity was also achieved under same CO2 pressure in presence of our synthesized catalyst at room temperature with solvent-free condition. The catalyst is reusable and e?cient even after six cycles.
- Khatun, Resmin,Biswas, Surajit,Islam, Sarikul,Biswas, Imdadul Haque,Riyajuddin, Sk,Ghosh, Kaushik,Islam, Sk Manirul
-
supporting information
p. 1303 - 1312
(2019/01/25)
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- Investigations into the carbonic anhydrase inhibition of COS-releasing donor core motifs
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Carbonyl sulfide (COS) releasing scaffolds are gaining popularity as hydrogen sulfide (H2S) donors through exploitation of the carbonic anhydrase (CA)-mediated hydrolysis of COS to H2S. The majority of compounds in this emerging class of donors undergo triggerable decomposition (often referred to as self-immolation) to release COS, and a handful of different COS-releasing structures have been reported. One benefit of this donation strategy is that numerous caged COS-containing core motifs are possible and are poised for development into self-immolative COS/H2S donors. Because the intermediate release of COS en route to H2S donation requires CA, it is important that the COS donor motifs do not inhibit CA directly. In this work, we investigate the cytotoxicity and CA inhibition properties of different caged COS donor cores, as well as caged CO2 and CS2 motifs and non-self-immolative control compounds. None of the compounds investigated exhibited significant cytotoxicity or enhanced cell proliferation at concentrations up to 100 μM in A549 cells, but we identified four core structures that function as CA inhibitors, thus providing a roadmap for the future development of self-immolative COS/H2S donor motifs.
- Steiger, Andrea K.,Zhao, Yu,Choi, Won Jin,Crammond, Alder,Tillotson, McKinna R.,Pluth, Michael D.
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p. 124 - 130
(2017/12/04)
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- Ureas as safe carbonyl sources for the synthesis of carbamates with deep eutectic solvents (DESs) as efficient and recyclable solvent/catalyst systems
-
A simple, efficient and eco-friendly one-pot synthesis of primary, N-mono- and N-disubstituted carbamates is developed from ureas. The corresponding carbamates were produced at 120 °C, within 18 h, and in the presence of a deep eutectic solvent as a recyclable catalytic system. The catalyst can be reused for several runs without any reduction in its activity. To demonstrate the utility of this approach, a wide variety of alcohols and phenols were studied to find a vast range of carbamate derivatives in moderate to high yields.
- Dindarloo Inaloo, Iman,Majnooni, Sahar
-
p. 13249 - 13255
(2018/08/21)
-
- COMPOUNDS AND USES THEREOF
-
The present invention features compounds useful in the treatment of neurological disorders. The compounds of the invention, alone or in combination with other pharmaceutically active agents, can be used for treating or preventing neurological disorders.
- -
-
Page/Page column 274; 275
(2018/05/17)
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- Direct Catalytic Synthesis of N-Arylcarbamates from CO2, Anilines and Alcohols
-
The direct catalytic synthesis of carbamates from CO2, amines and methanol was achieved by controlling both the reaction equilibrium and the reactivity of the three components. The combination of CeO2 and 2-cyanopyridine was an effective catalyst, providing various carbamates including N-arylcarbamates in high selectivities.
- Tamura, Masazumi,Miura, Ayaka,Honda, Masayoshi,Gu, Yu,Nakagawa, Yoshinao,Tomishige, Keiichi
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p. 4835 - 4839
(2018/10/15)
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- N-Arylation of Carbamates through Photosensitized Nickel Catalysis
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A highly efficient method of visible light mediated Ni(II)-catalyzed photoredox N-arylation of Cbz-amines/Boc-amines with aryl electrophiles at room temperature is reported. The methodology provides a common access to a wide variety of N-aromatic and N-heteroaromatic carbamate products that find use in the synthesis of several biologically active molecules and provides a distinct advantage over traditional palladium-catalyzed Buchwald reaction.
- Reddy, Leleti Rajender,Kotturi, Sharadsrikar,Waman, Yogesh,Ravinder Reddy, Vudem,Patel, Chirag,Kobarne, Ajinath,Kuttappan, Sasikumar
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p. 13854 - 13860
(2018/10/31)
-
- Green and efficient preparation method of rebamipide
-
The invention belongs to the technical field of medical synthesis and in particular relates to a green and efficient preparation method of rebamipide. The synthesis method provided by the invention has a green and simple route and the price of raw materials is low, so that industrial production is easy to realize. The invention further discloses a novel method for preparing aniline from benzoic acid.
- -
-
Paragraph 0021-0040
(2018/09/12)
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- Selective Synthesis of Secondary Arylcarbamates via Efficient and Cost Effective Copper-Catalyzed Mono Arylation of Primary Carbamates with Aryl Halides and Arylboronic Acids
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Abstract: An efficient, selective and cost-effective procedure has been developed for mono N-arylation of primary alkyl and benzyl carbamates with aryl iodides and bromides by incorporating CuI as an inexpensive and commercially available catalyst. Despite previous reports on C–N coupling reactions, this process does not need expensive ligands and takes advantage of readily available and inexpensive ethylenediamine (EDA) as the ligand. Reaction times were relatively short and related N-arylated carbamates were obtained in excellent yields. Interestingly, replacing CuI with Cu(OAc)2 allowed us to use arylboronic acids as coupling partner for this reaction. All products are well characterized by 1H- and 13C-NMR, MS, melting point, IR and CHNS techniques.
- Sardarian, Ali Reza,DindarlooInaloo, Iman,Zangiabadi, Milad
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p. 642 - 652
(2018/01/11)
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- An efficient one-pot synthesis of N,N′-disubstituted phenylureas and N-aryl carbamates using hydroxylamine-O-sulfonic acid
-
We have developed an efficient one-pot method for the microwave-assisted synthesis of ureas and carbamates via a proposed Lossen rearrangement. Herein we report the first examples of the direct conversion of benzoyl chlorides into N,N′-disubstituted ureas and N-aryl carbamates using hydroxylamine-O-sulfonic acid as reagent. Using our general method, we have produced 11 examples of N,N′-disubstituted phenylureas in yields up to 95% using various substituted anilines, and primary and secondary amines. Additionally, we were able to generate a series of N-aryl carbamates in moderate yields using primary, secondary and tertiary alcohols.
- Bao, Jennifer,Kuik, Dale,Tranmer, Geoffrey K.
-
supporting information
p. 5546 - 5553
(2018/06/12)
-
- A Simple, efficient, Catalyst-Free and Solvent-Less Microwave-Assisted process for N-Cbz Protection of Several amines
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A simple, green and chemo-selective method for the N-benzyloxycarbonylation of amines, β-amino alcohols, α-amino esters and sulfonamides has been developed under microwave irradiation. Good to excellent yields of the N-benzyloxy-carbamates compounds were obtained in short times without any side products.
- Aouf, Zineb,Mansouri, Rachida,Lakrout, Salah,Berredjem, Malika,Aouf, Nour-Eddine
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p. 151 - 156
(2017/08/02)
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- One-pot synthesis of carbamates and thiocarbamates from Boc-protected amines
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A highly efficient one-pot procedure for the synthesis of carbamates and thiocarbamates has been described. In the presence of 2-chloropyridine and trifluoromethanesulfonyl anhydride, the isocyanate intermediates were generated in situ for further reactions with alcohols and thiols to afford the desired carbamates and thiocarbamates in high yields.
- Kim, Hee-Kwon,Lee, Anna
-
supporting information
p. 4890 - 4892
(2016/10/21)
-
- Polymer- and Carbon Nanotube-Supported Heterogeneous Catalysts for the Synthesis of Carbamates from Halides, Amines, and CO2
-
Abstract: A series of tetraalkylammonium catalysts immobilized on polystyrene or carbon nanotubes were investigated in a reaction between alkyl halides, amines, and CO2. The yield of carbamates was up to 85?% at 100?°C and 1?MPa of CO2 after 3?h (first stage 25?°C, 1 h) in the presence of Cs2CO3 and DMF as a solvent. The best results were achieved in the case of large ammonium substituents (C4 and C6) in the catalyst, benzyl amine, and benzyl chloride as reagents. The catalysts retained their activity after at least five cycles when carefully dried between cycles. Both polymer and carbon nanotube supports were equally effective, but the latter were less prone to deactivation. Graphical Abstract: [Figure not available: see fulltext.]
- Krawczyk, Tomasz,Jasiak, Katarzyna,Kokolus, Aneta,Baj, Stefan
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p. 1163 - 1168
(2016/07/06)
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- A high-yielding, expeditious, and multicomponent synthesis of urea and carbamate derivatives by using triphenylphosphine/trichloroisocyanuric acid system
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An efficient method for the synthesis of urea and carbamate derivatives from amines and alcohols is described by using triphenylphosphine (PPh3)/trichloroisocyanuric acid system. The protocol allows for the preparation of symmetrical, unsymmetrical di, tri-, and tetra-substituted ureas and carbamates and is tolerant of a wide range of functional groups. To optimize the reaction conditions, experimental variables including temperature, the concentration of amine and alcohol, solvent, and reaction time were studied. Satisfactory yields were obtained at the optimized conditions. The present methodology is experimentally simple, mild, and represents a valuable alternative to the existing methods.
- Ghodsinia, Sara S.E.,Akhlaghinia, Batool
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p. 104 - 110
(2016/01/25)
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- Fe3O4@SiO2/Schiff base/Pd complex as an efficient heterogeneous and recyclable nanocatalyst for chemoselective: N -arylation of O -alkyl primary carbamates
-
An efficient, heterogeneous and cost effective method has been developed using an Fe3O4@SiO2/Schiff base/Pd complex as a magnetic and easily recyclable nanocatalyst for rapid and effective N-arylation of carbamates in good to excellent yield. The catalyst can be easily recovered and reused over six runs without significant decrease in the activity. Further highlights of this protocol are operational simplicity, versatility and relatively short reaction times.
- Sardarian,Zangiabadi,Inaloo, I. Dindarloo
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p. 92057 - 92064
(2016/10/11)
-
- N-Urethane protection of amines and amino acids in an ionic liquid
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An efficient, solvent-free protocol for the N-fluorenylmethoxycarbonylation and N-benzyloxycarbonylation of amines is described. The reaction of aliphatic and aromatic amines with FmocOSu and Cbz-Osu in [Bmim][BF4] at room temperature afforded the corresponding N-urethane derivatives in excellent yields and do not require any further purification. The method has been extended to the N-Fmoc and N-Cbz protection of amino acids. Absence of bases, very short reaction times, high yields, selectivity and ease of product separation are some advantages of this protocol.
- Di Gioia,Gagliardi,Leggio,Leotta,Romio,Liguori
-
p. 63407 - 63420
(2015/08/11)
-
- A synthetic approach to N -aryl carbamates via copper-catalyzed Chan-Lam coupling at room temperature
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A mild and efficient synthesis of N-arylcarbamates was achieved by reacting azidoformates with boronic acids in the presence of 10 mol % of copper chloride catalyst. The reaction proceeds readily in an open flask at room temperature without additional base, ligand, or additive. Rapid access to urea analogues via a two-step one-pot procedure is enabled by reacting N-arylcarbamates with aluminum-amine complexes. In addition, among several boronic acid derivatives prepared, dimethylphenyl boronate was found to react rapidly in its reaction with benzyl azidoformate, invoking in situ generation of this species in the catalytic cycle.
- Moon, Soo-Yeon,Kim, U. Bin,Sung, Dan-Bi,Kim, Won-Suk
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p. 1856 - 1865
(2015/02/19)
-
- Ester manufacturing method (by machine translation)
-
PROBLEM TO BE SOLVED: To produce an ester compound by transesterification using an inexpensive and low toxic inorganic compound. SOLUTION: Transesterification of an ester compound and an alcohol compound is carried out under the presence of lanthanum nitrate (for example, lanthanum nitrate hexahydrate) and a phosphine compound (for example, tri-n-octylphosphine), thereby obtaining the ester product. For example, transesterification of dimethyl carbonate and benzyl alcohol is carried out under the presence of 1 mol% of lanthanum nitrate hexahydrate, and 2 mol% of tri-n-octylphosphine, thereby obtaining benzyl methylcarbonate at a yield of >99%. COPYRIGHT: (C)2012,JPO&INPIT
- -
-
Paragraph 0079; 0080
(2017/02/17)
-
- Microwave-assisted expeditious synthesis of 5-fluoroalkyl-3-(aryl/alkyl)- oxazolidin-2-ones
-
An efficient and convenient protocol for synthesis of 5-fluoroalkyl-3- (aryl/alkyl)-oxazolidin-2-ones is described. The reaction of allyl (aryl/alkyl) carbamates with fluoroalkyl iodide initiated by sodium dithionite in aqueous acetonitrile resulted in adducts that undergoes a cyclization assisted by microwave irradiation to form 5-fluoroalkyl-3-(aryl/alkyl)-oxazolidin-2-ones with high yields. It was also found that the products can be more efficiently formed via an AIBN-initiated one-pot addition-cyclization sequence from benzyl allyl(aryl/alkyl) carbamates and fluoroalkyl iodide.
- Yang, Bo,Shi, Luyan,Wu, Jingjing,Fang, Xiang,Yang, Xueyan,Wu, Fanhong
-
supporting information
p. 3331 - 3337
(2013/04/24)
-
- Reaction of organozinc halides with aryl isocyanates
-
Reformatsky reagent, benzylzinc bromide or alkylzinc iodides react with aryl isocyanates directly to give corresponding N-substituted carbamates under mild reaction conditions. However, the reaction of allylzinc bromide or propargylzinc bromide with aryl isocyanates produces the corresponding N-substituted amides. The reactions provide alternative methods for the synthesis of N-substituted carbamates or amides.
- Yang, Haoran,Huang, Danfeng,Wang, Ke-Hu,Xu, Changming,Niu, Teng,Hu, Yulai
-
supporting information
p. 2588 - 2593
(2013/03/28)
-
- Mild and high-yielding molybdenum(VI) dichloride dioxide-catalyzed formation of Mono-, Di-, Tri-, and tetracarbamates from alcohols and aromatic or aliphatic isocyanates
-
Both molybdenum(VI) dichloride dioxide (MoO2Cl2) and its dimethylformamide (DMF) complex catalyze the addition of alcohols to isocyanates giving carbamates. Most additions proceeded to completion at room temperature within 20 min using as little as 0.1 mol% of the catalyst when working on a 1-mmol scale or just 100 ppm working on a 20-mmol scale. Sterically encumbered substrates reacted to completion when 1 mol% of the catalyst was employed. Diols, triols, and tetraols reacted with monoisocyanates likewise, as did monofunctional alcohols and diisocyanates. These pairings furnished di-, tri-, tetra-, and dicarbamates, respectively. Reactants, which were poorly soluble in CH2Cl2 at room temperature required elevating the temperature and possibly choosing a higher-boiling solvent (ClCH 2CH2Cl, DMF) as well. Additions of diols to diisocyanates were feasible, too, giving polycarbamates as we presume. Copyright
- Stock, Christian,Brueckner, Reinhard
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p. 2309 - 2330
(2012/11/07)
-
- Palladium-catalyzed oxidative arylalkylation of unactivated alkenes: Dual C-H bond cleavage of anilines and acetonitrile
-
A palladium-catalyzed oxidative arylalkylation of unactivated alkenes involving dual C-H bond cleavage of arene and acetonitrile was developed. This reaction was promoted by pyridine as a ligand, and the ratio of palladium to pyridine is vital for this transformation. A series of nitrile-containing indolines were efficiently provided in moderate to good yields. Copyright
- Zhang, Hao,Chen, Pinhong,Liu, Guosheng
-
supporting information
p. 2749 - 2752
(2013/02/22)
-
- Titanocene(III)-catalyzed conversion of N-(epoxyalkyl)anilines into indolines
-
Densely substituted indolines and azaindolines can be obtained by the titanocene(III) chloride catalyzed reductive opening of N-(oxiran-2-ylmethyl) anilines. The reaction optimization, substrate scope, and limitations are discussed, and a mechanistic pathway for the epoxideopening rearrangement is proposed. ARKAT-USA, Inc.
- MacIejewski, John P.,Wipf, Peter
-
experimental part
p. 92 - 119
(2011/06/20)
-
- HUMAN IMMUNODEFICIENCY VIRUS PROTEASE INHIBITORS
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The described invention relates to novel human immunodeficiency virus protease inhibitors, pharmaceutical compositions containing at least one such inhibitor, methods of preparing such inhibitors, and methods of utilizing such inhibitors to treat HIV and
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Page/Page column 43
(2011/05/16)
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- Amberlyst-15 catalyzed Cbz protection of amines under solvent-free conditions
-
Amberlyst-15 can effectively catalyze Cbz protection of aliphatic and aromatic amines within 10-15 min under solvent-free conditions. The catalyst can be used repeatedly without loss of activity, and the reaction requires no workup and gives excellent yields. Taylor & Francis Group, LLC.
- Bora, Pranja P.,Vanlaldinpuia, Khiangte,Rokhum, Lalthazuala,Bez, Ghanashyam
-
experimental part
p. 2674 - 2683
(2011/08/22)
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- A two-component small molecule system for activity-based detection and signal amplification: Application to the visual detection of threshold levels of Pd(II)
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A detection and signal amplification strategy aimed toward threshold diagnostic assays for use in resource-limited settings is described. The strategy employs two small molecule reagents that work in tandem. One reagent detects a specific analyte, while the second amplifies a colorimetric readout autocatalytically. The strategy is demonstrated using palladium(II) as a model analyte.
- Baker, Matthew S.,Phillips, Scott T.
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supporting information; experimental part
p. 5170 - 5173
(2011/05/19)
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- Bromodimethyl sulfonium bromide mediated rapid and facile protection of amines
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A new clean protocol for protection of aryl and aliphatic amines with t-butoxycarbonyl (t-BOC) and benzyloxycarbonyl (Cbz) catalyzed by simple (bromodimethyl) sulfonium bromide has been developed. Rapid protection of amines in excellent yields in totally solvent-free conditions has been achieved. Copyright
- Shailaja,Manjula,Vittal Rao
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experimental part
p. 2073 - 2080
(2011/07/31)
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- Synthesis of (-)-oseltamivir by using a microreactor in the curtius rearrangement
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A microflow reaction of the Curtius rearrangement by using trimethylsilyl azide as an azide source, followed by trapping of the generated isocyanate with a nucleophile was established, which is safe, inexpensive, and suitable for large-scale synthesis. By this flow reaction in the Curtius rearrangement and recrystallization of the late-stage acetamide intermediate the third-generation synthesis of (-)-Oseltamivir has been established, which is efficient, practical, and safe. A safe and efficient total synthesis of (-)-Oseltamivir has been developed by using the Curtius rearrangement with a microflow system, which avoids the isolation of a hazardous and potentially explosive intermediate. In addition, the product, possessing an acetamide group, was easily purified by recrystallization. Thus, this procedure can be scaled up as an industrial process.
- Ishikawa, Hayato,Bondzic, Bojan P.,Hayashi, Yujiro
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experimental part
p. 6020 - 6031
(2011/12/15)
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- Lanthanum(III) isopropoxide catalyzed chemoselective transesterification of dimethyl carbonate and methyl carbamates
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A practical transesterification of less reactive dimethyl carbonate and much less reactive methyl carbamates with primary (1°), secondary (2°), and tertiary (3°) alcohols was established with the use of a lanthanum(III) complex, which was prepared in situ from lanthanum (III) isopropoxide (3 mol %) and 2-(2-methoxyethoxy)ethanol (6 mol %). In particular, corresponding carbonates and carbamates obtained were of synthetic utility from the viewpoint of the selective protection and/or deprotection of 1°-, 2°-, and 3°-alcohols.
- Hatano, Manabu,Kamiya, Sho,Moriyama, Katsuhiko,Ishihara, Kazuaki
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supporting information; experimental part
p. 430 - 433
(2011/04/15)
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- Exceptionally active catalysts for the formation of carbamates from alcohols and isocyanates: Molybdenum(VI) dichloride dioxide and its DMF complex
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Small amounts of MoO2Cl2 or MoO2Cl 2(DMF)2 catalyze carbamate formation from an alcohol and isocyanates: 0.1 mol% of the respective additive allow primary, secondary or tertiary alcohols to add to aliphatic or aromatic isocyanates of varied steric hindrance within 20 minutes at room temperature. Typically the corresponding carbamate resulted in 100% yield. Only particularly hindered substrates required 1.0 mol% of the catalyst while as little as 0.01% sufficed for the phenylcarbamoylation of menthol. Catalytic amounts of DMAP accelerate carbamate formation from certain alcohols and isocyanates, too. Georg Thieme Verlag Stuttgart · New York.
- Stock, Christian,Brückner, Reinhard
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experimental part
p. 2429 - 2434
(2010/12/18)
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- 1-propanephosphonic acid cyclic anhydride (T3P) as an efficient promoter for the Lossen rearrangement: Application to the synthesis of urea and carbamate derivatives
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The synthesis of hydroxamic acids starting from carboxylic acids employing 1-propanephosphonic acid cyclic anhydride (T3P) activation is described. Application of ultrasonication accelerates this conversion. Further, the T3P has also been employed to activate the hydroxamates, leading to isocyanates via the Lossen rearrangement. The isocyanates were trapped with suitable nucleophiles to afford the corresponding ureas and carbamates. Georg Thieme Verlag Stuttgart New York.
- Vasantha, Basavalingappa,Hemantha, Hosahalli P.,Sureshbabu, Vommina V.
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experimental part
p. 2990 - 2996
(2010/10/21)
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- An excellent method for Cbz-protection of amines
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Cbz-protection of aliphatic and aromatic amines can be accomplished with benzylchloroformate using a catalytic amount of dodecatungstophosphoric acid hydrate (0.05 equiv). The reaction is simple, fast, does not require aqueous work-up and gives excellent yields.
- Vanlaldinpuia, Khiangte,Sema, H. Atoholi,Rokhum, Lalthazuala,Bez, Ghanashyam
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experimental part
p. 228 - 229
(2010/08/20)
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- Structure-based design, synthesis, and structure-activity relationship studies of HIV-1 protease inhibitors incorporating phenyloxazolidinones
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A series of new HIV-1 protease inhibitors with the hydroxyethylamine core and different phenyloxazolidinone P2 ligands were designed and synthesized. Variation of phenyl substitutions at the P2 and P2' moieties significantly affected the binding affinity and antiviral potency of the inhibitors. In general, compounds with 2- and 4-substituted phenyloxazolidinones at P2 exhibited lower binding affinities than 3-substituted analogues. Crystal structure analyses of ligand-enzyme complexes revealed different binding modes for 2- and 3-substituted P2 moieties in the protease S2 binding pocket, which may explain their different binding affinities. Several compounds with 3-substituted P2 moieties demonstrated picomolar binding affinity and low nanomolar antiviral potency against patient-derived viruses from HIV-1 clades A, B, and C, and most retained potency against drug-resistant viruses. Further optimization of these compounds using structure-based design may lead to the development of novel protease inhibitors with improved activity against drug-resistant strains of HIV-1.
- Ali, Akbar,Reddy, G. S. Kiran Kumar,Nalam, Madhavi N. L.,Anjum, Saima Ghafoor,Cao, Hong,Schiffer, Celia A.,Rana, Tariq M.
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scheme or table
p. 7699 - 7708
(2010/12/30)
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- Carbonyldiimidazole-mediated lossen rearrangement
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[Chemical Equation Presented] Carbonyldiimidazole (CDI) was found to mediate the Lossen rearrangement of various hydroxamic acids to isocyanates. This process is experimentally simple and mild, with imidazole and CO 2 being the sole stoichiometric byproduct. Significant for large-scale application, the method avoids the use of hazardous reagents and thus represents a green alternative to standard processing conditions for the Curtius and Hofmann rearrangements.
- Dube, Pascal,Fine Nathel, Noah F.,Vetelino, Michael,Couturier, Michel,Aboussafy, Claude Larrivee,Pichette, Simon,Jorgensen, Matthew L.,Hardink, Mark
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supporting information; experimental part
p. 5622 - 5625
(2010/03/02)
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- One-pot curtius rearrangement processes from carboxylic acids
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An efficient and practical synthesis of amine derivatives from carboxylic acids is described using new one-pot Curtius rearrangement processes. The preparation of carbamate-protected amines and anilines, as well as ureas was achieved in good to excellent yields on a multigram scale. Georg Thieme Verlag Stuttgart.
- Leogane, Olivier,Lebel, Helene
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scheme or table
p. 1935 - 1940
(2009/12/29)
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- A mild and efficient chemoselective: N-benzyloxycarbonylation of amines using TBAB a catalyst under solvent-free conditions
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We describe a mild and efficient method for the chemoselective N-benzyloxycarbonylation of amines by treatment amines and aminoesters with benzyloxycarbonyl chloride (Cbz-Cl) in the presence of TBAB under solvent-free in excellent yields. The method is ge
- Babu, Kothamasu Suresh,Rao, Vidadala Rama Subba,Rao, Ravu Ranga,Babu, Sakhamuri Sivaram,Rao, Janaswami Madhusudana
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experimental part
p. 393 - 396
(2009/10/17)
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- Hindered ureas as masked isocyanates: Facile carbamoylation of nucleophiles under neutral conditions
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Bigger is better: Sterically hindered dialkyl ureas undergo nucleophilic substitution at dramatically faster rates than their less hindered counterparts (see scheme). Steric decompression upon the formation of an intermediate isocyanate can explain this c
- Hutchby, Marc,Houlden, Chris E.,Gair Ford,Tyler, Simon N. G.,Gagne, Michel R.,Lloyd-Jones, Guy C.,Booker-Milburn, Kevin I.
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supporting information; experimental part
p. 8721 - 8724
(2010/01/16)
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- Titanocene(III)-catalyzed formation of indolines and azaindolines
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(Chemical Equation Presented) Reductive cyclization of epoxides tethered to substituted anilines and aminopyridines in the presence of 3 mol % of titanocene dichloride and stoichiometric manganese metal promotes a radical annulation to form 3,3-disubstituted indolines and azaindolines.
- Wipf, Peter,Maciejewski, John P.
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supporting information; experimental part
p. 4383 - 4386
(2009/05/30)
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