618-87-1Relevant academic research and scientific papers
Effect of Terminal Alkylation of Aryl and Heteroaryl Hydrazines in the Fischer Indole Synthesis
Schmidt, Michael A.
, (2021/04/12)
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.
The utilization of ball milling in synthesis of aryl guanidines through guanidinylation and N-Boc-deprotection sequence
?ud, Mateja,Glasovac, Zoran,Margeti?, Davor
, p. 109 - 115 (2018/11/30)
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.
Coumarin-based fluorogenic agents and uses thereof for specific protein labelling
-
Page/Page column 40; 41, (2017/08/08)
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.
One-pot synthesis of primary amines from carboxylic acids through rearrangement of in situ generated hydroxamic acid derivatives
Hoshino, Yujiro,Ohtsuka, Naoya,Okada, Takuya,Honda, Kiyoshi
, p. 5304 - 5307 (2016/11/16)
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.
Fluorescent markers and use thereof for labeling specific protein targets
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Page/Page column 21, (2014/09/29)
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.
Tris(triazolo)benzene and its derivatives: High-density energetic materials
Thottempudi, Venugopal,Forohor, Farhad,Parrish, Damon A.,Shreeve, Jean'Ne M.
supporting information, p. 9881 - 9885 (2012/11/07)
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
Dramatic increase of quench efficiency in "spacerless" dimaleimide fluorogens
Caron, Karine,Lachapelle, Virginie,Keillor, Jeffrey W.
experimental part, p. 185 - 197 (2011/02/23)
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.
Preparation of nitroanilines by ammonolysis of multinitrobenzenes
Qianchao,Jinqiang, Liu,Xinzhi, Chen
scheme or table, p. 2782 - 2786 (2009/04/04)
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.
Selective reduction of one, two, or three nitro groups in 1,3,5-trinitrobenzene with hydrazine hydrate
Shakhnes,Vorob'Ev,Shevelev
, p. 938 - 939 (2008/02/04)
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.
Scandium(III) catalysis of transimination reactions. Independent and constitutionally coupled reversible processes
Giuseppone, Nicolas,Schmitt, Jean-Louis,Schwartz, Evan,Lehn, Jean-Marie
, p. 5528 - 5539 (2007/10/03)
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.
