13493-47-5Relevant articles and documents
Activated Self-Resolution and Error-Correction in Catalytic Reaction Networks**
Schaufelberger, Fredrik,Ramstr?m, Olof
supporting information, p. 10335 - 10340 (2021/05/07)
Understanding the emergence of function in complex reaction networks is a primary goal of systems chemistry and origin-of-life studies. Especially challenging is to create systems that simultaneously exhibit several emergent functions that can be independently tuned. In this work, a multifunctional complex reaction network of nucleophilic small molecule catalysts for the Morita-Baylis-Hillman (MBH) reaction is demonstrated. The dynamic system exhibited triggered self-resolution, preferentially amplifying a specific catalyst/product set out of a many potential alternatives. By utilizing selective reversibility of the products of the reaction set, systemic thermodynamically driven error-correction could also be introduced. To achieve this, a dynamic covalent MBH reaction based on adducts with internal H-transfer capabilities was developed. By careful tuning of the substituents, rate accelerations of retro-MBH reactions of up to four orders of magnitude could be obtained. This study thus demonstrates how efficient self-sorting of catalytic systems can be achieved through an interplay of several complex emergent functionalities.
Metal-Free C-C/C-N/C-C Bond Formation Cascade for the Synthesis of (Trifluoromethyl)sulfonylated Cyclopenta[ b]indolines
Lázaro-Milla, Carlos,Yanai, Hikaru,Almendros, Pedro
, p. 2921 - 2926 (2021/05/05)
A bis(triflyl)ethylation [triflyl = (trifluoromethyl)sulfonyl] inserted into a sequential cyclization cascade resulted in the direct formation of gem-bis(triflyl)ated cyclopenta[b]indolines from anilide-derived allenols and alkenols. This catalyst- and irradiation-free sequence facilitated the efficient preparation of functionalized tricyclic indoline cores bearing two contiguous stereocenters. The formed cyclopenta[b]indolines can be easily transformed into a wide variety of triflylated indolines, including the tetracycle ring system found in polyveoline.
NOVEL IMIDAZO-PYRAZINE DERIVATIVES
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, (2021/12/31)
The invention provides novel imidazo-pyrazine derivatives having the general formula (I), and pharmaceutically acceptable salts thereof, wherein X, m, n, and R1to R3 are as described herein: formula (I). Further provided are pharmace
A Convenient Formal [4+2] Heterocylization Route to Bis(triflyl)tetrahydroquinolines
Lázaro-Milla, Carlos,Almendros, Pedro
supporting information, p. 13534 - 13538 (2021/08/13)
We report the sustainable and efficient synthesis of a new type of quinoline derivatives bearing one or two SO2CF3 groups. The protocol is metal-, catalyst- and irradiation-free, involves the use of readily available and stable precursors, and avoids the formation of side products. Also, the mild conditions of the process allow the tolerance of a wide range of functional groups.
Toward the Rational Design of Universal Dual Polarity Matrix for MALDI Mass Spectrometry
Chou, Pi-Tai,Hsu, Cheng-Chih,Huang, Chun-Ying,Huang, Penghsuan,Lee, Chuping,Lin, Li-En,Lin, Ta-Chun,Yang, Ethan
, p. 7139 - 7145 (2020/07/21)
A series of novel anthranilic acid derivatives I-IV, of which COOH-NH2 (I) and COOH-NHMe (IV) are endowed with acid and base bifunctionality, were designed and synthesized for matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry applications in dual polarity molecular imaging of biological samples, particularly for lipids. The heat of protonation, deprotonation, and proton transfer reaction as well as the capability of analyzing biomolecules in both positive and negative ion modes for I-IV were systematically investigated under standard 355 nm laser excitation. The results indicate correlation between dual polarity and acid-base property. Further, COOH-NHMe (IV) showed a unique performance and was successfully applied as the matrix for MALDI-TOF mass spectrometry imaging (MSI) for studying the mouse brain. Our results demonstrate the superiority of COOH-NHMe (IV) in detecting more lipid and protein species compared to commercially available matrices. Moreover, MALDI-TOF MSI results were obtained for lipid distributions, making COOH-NHMe (IV) a potential next generation universal matrix.
KMnO4-catalyzed chemoselective deprotection of acetate and controllable deacetylation-oxidation in one pot
Gurawa, Aakanksha,Kumar, Manoj,Rao, Dodla S.,Kashyap, Sudhir
supporting information, p. 16702 - 16707 (2020/10/27)
A novel and efficient protocol for chemoselective deacetylation under ambient conditions was developed using catalytic KMnO4. The stoichiometric use of KMnO4 highlighted the dual role of a heterogeneous oxidant enabling direct access to aromatic aldehydes in one-pot sequential deacetylation-oxidation. The reaction employed an alternative solvent system and allowed the clean transformation of benzyl acetate to sensitive aldehyde in a single step while preventing over-oxidation to acids. Use of inexpensive and readily accessible KMnO4 as an environmentally benign reagent and the ease of the reaction operation were particularly attractive, and enabled the controlled oxidation and facile cleavage of acetate in a preceding step. This journal is
Modulation of imine chemistry with intramolecular hydrogen bonding: Effects from ortho-OH to NH
Chen, Hang,Feng, Zelin,Jia, Shuaipeng,You, Lei
, (2020/03/24)
Salicylaldehyde derivatives and their imines are important building blocks in organic and supramolecular chemistry. In an effort to expand structural diversity in the current work we changed ortho-OH in salicylaldehyde to NH of amide/sulfonamide and investigated the effect of resulting intramolecular hydrogen bonds on imine dynamic covalent chemistry (DCC). A suite of ortho-aminobenzaldehydes were readily synthesized, and X-ray and NMR data validated the existence of NH?O intramolecular hydrogen bonds. The formation and exchange of imines were then studied in acetonitrile, and the acidity of OH/NH significantly influenced the thermodynamics and kinetics of imine reactions. Furthermore, the role of OH/NH?N hydrogen bonds on imines was elucidated by the shift of aldehyde exchange equilibrium. Finally, the formation of imines was achieved in aqueous solutions. The mechanistic insights could pave the way for future applications in assembly and labelling.
Divergence in Ynone Reactivity: Atypical Cyclization by 3,4-Difunctionalization versus Rare Bis(cyclization)
Alcaide, Benito,Almendros, Pedro,Lázaro-Milla, Carlos,Delgado-Martínez, Patricia
, p. 8186 - 8194 (2018/06/15)
Functionalized ynones can be activated by Tf2C=CH2, which was generated in situ, to form zwitterionic species. These species were trapped in an intramolecular fashion by several nucleophiles to generate two major types of triflones in a divergent manner. Through fine-tuning of the reaction temperature, bis(triflyl)-6-membered- or (triflyl)-5-membered-fused-heterocycles were achieved in reasonable yields in a totally selective manner. In this way, bis(triflyl)flavones, bis(triflyl)thioflavones, bis(triflyl)selenoflavones, (triflyl)benzothienopyrans, (triflyl)benzoselenophenopyrans, (triflyl)vinyl aurones, and (triflyl)pyranoindoles were constructed. Conceivable mechanistic pathways were suggested on the basis of the isolation of several intermediates and the results from control experiments.
Experimental and computational studies on H2O-promoted, Rh-catalyzed transient-ligand-free ortho-C(sp2)-H amidation of benzaldehydes with dioxazolones
Ding, Jun,Jiang, Wei,Bai, He-Yuan,Ding, Tong-Mei,Gao, Dafang,Bao, Xiaoguang,Zhang, Shu-Yu
supporting information, p. 8889 - 8892 (2018/08/17)
An efficient and convenient ligand-free, rhodium-catalyzed ortho-C(sp2)-H amidation of benzaldehydes with dioxazolones using H2O as the key promoter is described. Using this protocol, a wide range of benzaldehyde substrates were selectively amidated in good to excellent yields with broad functional group compatibility. KIE experiments revealed that the C-H bond activation was likely the rate-limiting step. In addition, computational studies indicated that the catalyst precursor interacted with water and dioxazolones to generate the active catalytic species. Notably, the practicality and efficacy of this method were illustrated by a late-stage amidation of an estrone-derived molecule and further transformations of the amidated product.
(Z)-selective Takai olefination of salicylaldehydes
Geddis, Stephen M.,Hagerman, Caroline E.,Galloway, Warren R. J. D.,Sore, Hannah F.,Goodman, Jonathan M.,Spring, David R.
supporting information, p. 323 - 328 (2017/03/14)
The Takai olefination (or Takai reaction) is a method for the conversion of aldehydes to vinyl iodides, and has seen widespread implementation in organic synthesis. The reaction is usually noted for its high (E)-selectivity; however, herein we report the
