- Effect of Terminal Alkylation of Aryl and Heteroaryl Hydrazines in the Fischer Indole Synthesis
-
The effect of alkylation on the terminal position of aryl and heteroaryl hydrazines in the Fischer indole synthesis was examined. Compared to their unalkylated counterparts, reactions using alkylated hydrazines provided indole products with higher yields and faster rates. The reactions can be conducted at lower temperatures and are compatible with acid-sensitive functionality. The terminally alkylated hydrazines were readily prepared by a new two-step sequence and held as stable hydrazinium salts. The mild formation of the salts along with the favorable Fischer indole reaction conditions highlights the potential of this approach in later-stage synthetic use.
- Schmidt, Michael A.
-
-
- The utilization of ball milling in synthesis of aryl guanidines through guanidinylation and N-Boc-deprotection sequence
-
Solid state ball milling was used in guanidinylation reactions of aromatic amines with N,N′-Di-Boc-1H-pyrazole-1-carboxamidine reagent. Reaction conditions are advantageous, and in general reactions proceed in significantly shorter reaction times and in higher yields than under the conventional solution conditions. Mechanochemical conditions were also successfully applied to the cleavage of N-Boc protecting group.
- ?ud, Mateja,Glasovac, Zoran,Margeti?, Davor
-
p. 109 - 115
(2018/11/30)
-
- Coumarin-based fluorogenic agents and uses thereof for specific protein labelling
-
There are provided fluorescent labelling agents comprising a dimaleimide core connected to a fluorophore, processes for preparation thereof, and uses thereof for labelling and/or detection of specific protein targets. Fluorescent labelling agents comprising a compound having the structure of Formula I, and salts thereof, are described.
- -
-
Page/Page column 40; 41
(2017/08/08)
-
- One-pot synthesis of primary amines from carboxylic acids through rearrangement of in situ generated hydroxamic acid derivatives
-
A one-pot synthesis of primary amines from carboxylic acids through a Lossen rearrangement of hydroxamic acid derivatives, which were in situ generated by the reaction of carboxylic acids with O-trimethylsilylhydroxylamine (NH2OTMS) and carbonyl diimidazole (CDI, 1.5 equiv) in dimethyl sulfoxide at room temperature, has been achieved. This one-pot method could be applied to various carboxylic acids such as aromatic, heteroaromatic, aliphatic, and optically active substrates.
- Hoshino, Yujiro,Ohtsuka, Naoya,Okada, Takuya,Honda, Kiyoshi
-
supporting information
p. 5304 - 5307
(2016/11/16)
-
- Fluorescent markers and use thereof for labeling specific protein targets
-
Novel fluorescent markers of Formula I: are disclosed herein, wherein X and Y are independently or together absent or are independently selected from R and R1 are independently selected from H and alkyl; Ar is phenyl or heteroaryl; L is absent or a spacer selected from the group consisting of —NH—; —(CH2)nNH—; —NHSO2—; —(CH2)nNHCO—; -(cycloalkyl)NHCO—; —(CH2)nNHSO2—; -(cycloalkyl)NHSO2—; —CONH(CH2)nNHCO—; —CONH(cycloalkyl)NHCO—; —NHCO(CH2)nNHCO—; —NHCO(cycloalkyl)NHCO—; —(CH2)nSO2NH—; -(cycloalkyl)SO2NH—; —(CH2)nNHCSNH—; -(cycloalkyl)NHCSNH—; —CR═CR1—; —C≡C—; —(CH2)nN═CH—; -(cycloalkyl)N═CH—; —N═CH(CH2)—; —N═CH(cycloalkyl)-; n is an integer ranging from 1 to 5; F is a fluorophore selected from the group consisting of fluorescein, rhodamine, eosin, thionine, safranin, coumarin, methoxycoumarin, dansyl, BODIPY and BODIPY derivatives; and wherein X, Y and L may be positioned in a 1,3,5; 1,2,3; 1,3,4 or in a 3,4,5 configuration respectively.
- -
-
Page/Page column 21
(2014/09/29)
-
- Tris(triazolo)benzene and its derivatives: High-density energetic materials
-
High-performance explosives: Tris(triazolo)benzene was synthesized and converted to its trinitro and trichloro derivatives (see scheme; R=NO 2, Cl). The heats of formation of this "high-nitrogen" compounds were calculated and combined with experimentally determined densities to determine detonation pressures and velocities. They exhibit high density, good thermal stability, high heats of formation, and moderate to good detonation properties. Copyright
- Thottempudi, Venugopal,Forohor, Farhad,Parrish, Damon A.,Shreeve, Jean'Ne M.
-
supporting information
p. 9881 - 9885
(2012/11/07)
-
- Dramatic increase of quench efficiency in "spacerless" dimaleimide fluorogens
-
In this post-genomic era, new techniques are needed to cope with the task of assigning functional roles to the huge number of identified putative gene products. We have developed a minimalist labelling strategy based on the use of synthetic fluorogenic probe reagents that fluoresce only after their reaction with a target peptide sequence. The probe reagents have fluorescent cores and bear two maleimide groups, such that their latent fluorescence is quenched by a photoinduced electron transfer (PET) to the pendant maleimide groups, until both of these groups undergo a specific thiol addition reaction. The efficiency of the fluorescence quenching is critical to the practicality of this labelling method, and has been predicted to be related to the intramolecular distance between the fluorophore and the maleimide groups. We have conducted the first direct test of this hypothesis by preparing a series of novel fluorogens that differ only by the spacer moiety separating their coumarin fluorophore and their dimaleimide fragment. A striking correlation was observed between intramolecular distance and the fluorescence enhancement (FE) observed after reaction with two equivalents of thiol. Guided by this observation, we then designed 'spacerless' fluorogens, of which a dansyl derivative shows an FE ratio of >300, the largest recorded for dimaleimide fluorogens. The trends observed herein provide valuable lessons for subsequent fluorogen design, and the novel fluorogens developed in the course of this study are currently being applied to protein labelling applications.
- Caron, Karine,Lachapelle, Virginie,Keillor, Jeffrey W.
-
experimental part
p. 185 - 197
(2011/02/23)
-
- Preparation of nitroanilines by ammonolysis of multinitrobenzenes
-
Highly efficient ammonolysis of several multinitrobenzenes to the corresponding nitroanilines was achieved by aqueous ammonia. o-Dinitrobenzene on reaction with 8 equiv. of ammonia produce the o-nitroaniline in yields of 87%. Similar reactions with p-dinitrobenzene, m-dinitrobenzene, and trinitrobenzene produce p-nitroaniline, m-nitroaniline, and 3,5-dinitroaniline, in yields of 86%, 45%, and 84%, respectively. Copyright Taylor & Francis Group, LLC.
- Qianchao,Jinqiang, Liu,Xinzhi, Chen
-
scheme or table
p. 2782 - 2786
(2009/04/04)
-
- Selective reduction of one, two, or three nitro groups in 1,3,5-trinitrobenzene with hydrazine hydrate
-
A method was developed for successive selective reduction of one, two, or three nitro groups in 1,3,5-trinitrobenzene with hydrazine hydrate in the presence of iron chloride and charcoal. This method provides an approach to the one-pot synthesis of 3,5-dinitroaniline, 1,3-diamino-5-nitrobenzene, or 1,3,5-triaminobenzene from 1,3,5-trinitrobenzene. Springer Science+Business Media, Inc. 2006.
- Shakhnes,Vorob'Ev,Shevelev
-
p. 938 - 939
(2008/02/04)
-
- Scandium(III) catalysis of transimination reactions. Independent and constitutionally coupled reversible processes
-
Sc(OTf)3 efficiently catalyzes the self-sufficient transimination reaction between various types of C=N bonds in organic solvents, with turnover frequencies up to 3600 h-1 and rate accelerations up to 6 × 105. The mechanism of the crossover reaction in mixtures of amines and imines is studied, comparing parallel individual reactions with coupled equilibria. The intrinsic kinetic parameters for isolated reactions cannot simply be added up when several components are mixed, and the behavior of the system agrees with the presence of a unique mediator that constitutes the core of a network of competing reactions. In mixed systems, every single amine or imine competes for the same central hub, in accordance with their binding affinity for the catalyst metal ion center. More generally, the study extends the basic principles of constitutional dynamic chemistry to interconnected chemical transformations and provides a step toward dynamic systems of increasing complexity.
- Giuseppone, Nicolas,Schmitt, Jean-Louis,Schwartz, Evan,Lehn, Jean-Marie
-
p. 5528 - 5539
(2007/10/03)
-
- Nitroanilinodinitrobenzofuroxans - Synthesis, characterisation, thermal stability and explosive properties
-
Three new derivatives of 4,6-dinitrobenzofuroxan: 7-(4-nitrophenylamino)-4,6-dinitrobenzofuroxan, 7-(3,5-dinitrophenylamino)-4,6-dinitrobenzofuroxan and 7-(2,4,6-trinitrophenylamino)-4,6-dinitrobenzofuroxan, have been synthesised by condensing 4-nitroaniline, 3,5-dinitroaniline and 2,4,6-trinitroaniline with 7-chloro-4,6-dinitrobenzofuroxan, respectively. The characterisation of the compounds by IR, 1H-NMR, mass spectrometry and elemental analysis is described along with some of the evaluated preliminary explosive properties. The compounds were found to exhibit acceptable hazards properties. Furthermore, the thermal stability measurements indicated acceptable stability.
- Mehilal,Sikder,Salunke,Sikder
-
p. 1549 - 1552
(2007/10/03)
-
- Thermal Stability Studies on a Homologous Series of Nitroarenes
-
The thermal stabilities of a number of nitroarenes were examined in solution and in condensed phase.In general, increasing the number of nitro groups decreased thermal stability.Changing the substituent on 1-X-2,4,6-trinitrobenzene from X = H to NH2 to CH3 to OH accelerated decomposition; this effect was attributed to increased ease of intramolecular proton transfer to an ortho nitro group, thus weakening the carbon-nitrogen bond.In solution, the effect of increasing substitution from n = 1 to n = 3 on Xn(NO2)3C6H3-n was uniformly that of decreasing the thermal stability of the species.However, in condensed phase, results suggested that crystal habit may be more important than molecular structure; for X = Br, CH3, and NH2, the more substituted species was the more stable.
- Oxley, Jimmie C.,Smith, James L.,Ye, Hong,McKenney, Robert L.,Bolduc, Paul R.
-
p. 9593 - 9602
(2007/10/02)
-
- Synthesis of aminonitrobenzodifuroxan
-
Aminonitrobenzodifuroxan (CL-18) is prepared by directly converting pentanitroaniline to aminonitrobenzodifuroxan with heat in the presence of an excess of sodium azide. The pentanitroaniline is prepared in high yield from 3,5-dinitroaniline with a mixture of nitric acid and sulfuric acid in which the final sulfuric acid concentration is from 99.0 to 99.5%.
- -
-
-
- Synthesis of Polynitro Compounds. Peroxydisulfuric Acid Oxidation of Polynitroarylamines to Polynitro Aromatics.
-
Peroxydisulfuric acid in sulfuric acid solution, prepared by reaction of hydrogen peroxide with excess oleum or 100percent H2SO4, oxidizes primary polynitroarylamines and their N-acetamido derivatives to polynitro aromatics in good to excellent yields.The new procedure is illustrated by the synthesis of several new polynitro compounds, not preparable by known synthetic methods.Peroxytrifluoromethanesulfonic acid is comparably efficient for such oxidations.The scope and limitations of the new reaction have been examined and compared to other methods of synthesis of polynitro compounds.
- Nielsen, Arnold T.,Atkins, Ronald L.,Norris, William P.,Coon, Clifford L.,Sitzmann, Michael E.
-
p. 2341 - 2347
(2007/10/02)
-
- The Kinetics of the Reactions of Picryl Chloride with Some Substituted Anilines. Part 5.
-
Arrhenius parameters have been measured for the reactions of picryl chloride with the following substituted anilines in acetonitrile: 3-amino- and 3-methyl-aniline, 3-amino-5-nitroaniline, 3-fluoro-5-methylsulphonylaniline, 3-X-5-methylanilines (X=NO2, OMe, CH3, F, Cl, Br, or I) and 3,5-X2-anilines (X = F, Cl, Br, or I).A total of 33 3,5-disubstituted anilines have now been examined for the additivity of substituent effects on the free energy of activation, and it has been shown that with the exception of 3-amino-5-nitroaniline this hypothesis reproduces experimental rate constants within a factor of 2.A rationalization is proposed for the deviations that occur in some cases when more stringent criteria of additivity are used.
- Emokpae, Thomas A.,Eguavoen, Osa,Hirst, Jack
-
p. 829 - 831
(2007/10/02)
-