72846-70-9Relevant academic research and scientific papers
Pharmacological characterization of a new series of carbamoylguanidines reveals potent agonism at the H2R and D3R
Biselli, Sabrina,Bresinsky, Merlin,Buschauer, Armin,Forster, Lisa,Honisch, Claudia,Pockes, Steffen,Tropmann, Katharina,Bernhardt, Günther
supporting information, (2021/02/12)
Even today, the role of the histamine H2 receptor (H2R) in the central nervous system (CNS) is widely unknown. In previous research, many dimeric, high-affinity and subtype-selective carbamoylguanidine-type ligands such as UR-NK22 (5, pKi = 8.07) were reported as H2R agonists. However, their applicability to the study of the H2R in the CNS is compromised by their molecular and pharmacokinetic properties, such as high molecular weight and, consequently, a limited bioavailability. To address the need for more drug-like H2R agonists with high affinity, we synthesized a series of monomeric (thio)carbamoylguanidine-type ligands containing various spacers and side-chain moieties. This structural simplification resulted in potent (partial) agonists (guinea pig right atrium, [35S]GTPγS and β-arrestin2 recruitment assays) with human (h) H2R affinities in the one-digit nanomolar range (pKi (139, UR-KAT523): 8.35; pKi (157, UR-MB-69): 8.69). Most of the compounds presented here exhibited an excellent selectivity profile towards the hH2R, e.g. 157 being at least 3800-fold selective within the histamine receptor family. The structural similarities of our monomeric ligands to pramipexole (6), a dopamine receptor agonist, suggested an investigation of the binding behavior at those receptors. The target compounds were (partial) agonists with moderate affinity at the hD2longR and agonists with high affinity at the hD3R (e.g. pKi (139, UR-KAT523): 7.80; pKi (157, UR-MB-69): 8.06). In summary, we developed a series of novel, more drug-like H2R and D3R agonists for the application in recombinant systems in which either the H2R or the D3R is solely expressed. Furthermore, our ligands are promising lead compounds in the development of selective H2R agonists for future in vivo studies or experiments utilizing primary tissue to unravel the role and function of the H2R in the CNS.
Photocatalyzed Triplet Sensitization of Oximes Using Visible Light Provides a Route to Nonclassical Beckmann Rearrangement Products
Zhang, Xiao,Rovis, Tomislav
supporting information, p. 21211 - 21217 (2021/12/27)
Oximes are valuable synthetic intermediates for the preparation of a variety of functional groups. To date, the stereoselective synthesis of oximes remains a major challenge, as most current synthetic methods either provide mixtures of E and Z isomers or furnish the thermodynamically preferred E isomer. Herein we report a mild and general method to achieve Z isomers of aryl oximes by photoisomerization of oximes via visible-light-mediated energy transfer (EnT) catalysis. Facile access to (Z)-oximes provides opportunities to achieve regio- and chemoselectivity complementary to those of widely used transformations employing oxime starting materials. We show an enhanced one-pot protocol for photocatalyzed oxime isomerization and subsequent Beckmann rearrangement that enables novel reactivity with alkyl groups migrating preferentially over aryl groups, reversing the regioselectivity of the traditional Beckmann reaction. Chemodivergent N- or O- cyclizations of alkenyl oximes are also demonstrated, leading to nitrones or cyclic oxime ethers, respectively.
Copper-catalyzed synthesis of oxime ethers from iminoxy radical (C[dbnd]N–O[rad]) and maleimides via radical addition
Han, Ziwei,Shen, Subo,Zheng, Feng,Hu, Han,Zhang, Jianmin,Zhu, Shizheng
supporting information, (2019/09/30)
An efficient Cu(II)-catalyzed radical addition of maleimides has been achieved. The identified copper catalyst enables the formation of oxime radicals (N–O[rad]) by cleaving the O–H bond in ketoximes, followed by the radical addition to N-substituted male
Copper-Catalyzed Unstrained C-C Single Bond Cleavage of Acyclic Oxime Acetates Using Air: An Internal Oxidant-Triggered Strategy toward Nitriles and Ketones
Zhu, Chuanle,Chen, Fulin,Liu, Chi,Zeng, Hao,Yang, Zhiyi,Wu, Wanqing,Jiang, Huanfeng
, p. 14713 - 14722 (2018/12/14)
A copper-catalyzed aerobic oxidative C-C single bond cleavage of acyclic unstrained oxime acetates is reported, providing various aryl nitriles and ketones in good yields. Mechanistic studies indicate a radical procedure is involved in this transformation, and the oxygen atom in the ketone products is originated from O2 in the air. Oxime acetates as an internal oxidant have been proved to be an initiator, which may promote the discovery of novel protocol for C-C bond cleavage and dioxygen activation.
Scope and mechanism of a true organocatalytic beckmann rearrangement with a boronic acid/perfluoropinacol system under ambient conditions
Mo, Xiaobin,Morgan, Timothy D. R.,Ang, Hwee Ting,Hall, Dennis G.
supporting information, p. 5264 - 5271 (2018/04/24)
Catalytic activation of hydroxyl functionalities is of great interest for the production of pharmaceuticals and commodity chemicals. Here, 2-alkoxycarbonyl- and 2-phenoxycarbonyl-phenylboronic acid were identified as efficient catalysts for the direct and chemoselective activation of oxime N-OH bonds in the Beckmann rearrangement. This classical organic reaction provides a unique approach to prepare functionalized amide products that may be difficult to access using traditional amide coupling between carboxylic acids and amines. Using only 5 mol % of boronic acid catalyst and perfluoropinacol as an additive in a polar solvent mixture, the operationally simple protocol features mild conditions, a broad substrate scope, and a high functional group tolerance. A wide variety of diaryl, aryl-alkyl, heteroaryl-alkyl, and dialkyl oximes react under ambient conditions to afford high yields of amide products. Free alcohols, amides, carboxyesters, and many other functionalities are compatible with the reaction conditions. Investigations of the catalytic cycle revealed a novel boron-induced oxime transesterification providing an acyl oxime intermediate involved in a fully catalytic nonself-propagating Beckmann rearrangement mechanism. The acyl oxime intermediate was prepared independently and was subjected to the reaction conditions. It was found to be self-sufficient; it reacts rapidly, unimolecularly without the need for free oxime. A series of control experiments and 18O labeling studies support a true catalytic pathway involving an ionic transition structure with an active and essential role for the boronyl moiety in both steps of transesterification and rearrangement. According to 11B NMR spectroscopic studies, the additive perfluoropinacol provides a transient, electrophilic boronic ester that is thought to serve as an internal Lewis acid to activate the ortho-carboxyester and accelerate the initial, rate-limiting step of transesterification between the precatalyst and the oxime substrate.
Axial stereocontrol in: Tropos dibenz [c, e] azepines: The individual and cooperative effects of alkyl substituents
Balgobin, Sinead M. C.,Brookes, Dominic J.,Jiang, Junxiang,Pritchard, Robin G.,Wallace, Timothy W.
supporting information, p. 10184 - 10199 (2017/12/26)
6,7-Dihydro-5H-dibenz[c,e]azepines, a class of secondary amine incorporating a centre-axis chirality relay, can be prepared from N-(2-bromobenzyl)-N-(1-arylalkyl)methanesulfonamides via Pd-catalysed intramolecular direct arylation, and methylated at C(7)
The fullerene dieno 3, 4 - dihydro pyrrole derivative and its preparation method
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Paragraph 0052, (2017/10/31)
The invention relates to a fullereno-3,4-dihydropyrrole derivative and a preparation method thereof. The compound has the structure as shown in the specification, wherein R1 is -Ar or -CH3; R2 is -H or -CH3; and R3 is -H, -CH3 or -Ph. The novel [60] fullereno-3,4-dihydropyrrole compound indicates that [60]fullerene exhibits uniqueness in structure and has specialty in reactivity which is deficient in general substances. As an important intermediate of fine chemical products, the product dihydropyrrole has wide application in the fields such as medicines, pesticides, coatings, daily chemicals and polymer materials.
C-H Activation Induced by Oxidative Addition of N-O Bonds in Oxime Esters: Formation of Rhodacycles and Cycloaddition with Alkynes
Shimbayashi, Takuya,Okamoto, Kazuhiro,Ohe, Kouichi
supporting information, p. 2026 - 2031 (2016/07/06)
The reaction of oxime esters with a rhodium(I) precursor to form five-membered rhodacycles via N-O bond cleavage followed by C-H bond activation has been investigated by isolating these complexes. Kinetic studies on the formation of rhodacycles show that the reversible oxidative addition of the N-O bond in the oxime ester to RhCl(PPh3)3 occurs at room temperature. The E-isomer of the oxime ester was found to undergo rhodacycle formation faster than the Z-isomer, which suggests that the geometry of the oxime esters reflects the geometry of intermediates during C-H activation. The rhodacycle reacted with an alkyne to construct an isoquinoline ring in both stoichiometric and catalytic conditions, despite its basic stability in air, in moisture, and even during heating, which demonstrates the potential of the rhodacycle as an intermediate for further catalytic transformation of oxime esters.
Rh(III)- and Zn(II)-Catalyzed Synthesis of Quinazoline N-Oxides via C-H Amidation-Cyclization of Oximes
Wang, Qiang,Wang, Fen,Yang, Xifa,Zhou, Xukai,Li, Xingwei
supporting information, p. 6144 - 6147 (2016/12/09)
Quinazoline N-oxides have been prepared from simple ketoximes and 1,4,2-dioxazol-5-ones via Rh(III)-catalyzed C-H activation-amidation of the ketoximes and subsequent Zn(II)-catalyzed cyclization. The substrate scope and functional group compatibility were examined. The reaction features relay catalysis by Rh(III) and Zn(II).
Palladium-Catalyzed C-H Functionalization of Aromatic Oximes: A Strategy for the Synthesis of Isoquinolines
Zhu, Zhongzhi,Tang, Xiaodong,Li, Xianwei,Wu, Wanqing,Deng, Guohua,Jiang, Huanfeng
, p. 1401 - 1409 (2016/03/01)
An efficient strategy for synthesis of isoquinolines via Pd(II)-catalyzed cyclization reaction of oximes with vinyl azides or homocoupling of oximes is reported. Oximes could serve as a directing group and an internal oxidant in the transformation. This reaction features good functional group tolerance and provides a useful protocol for the synthesis of different kinds of isoquinolines under mild conditions. Some control experiments and 15N isotope labeling experiments were conducted for the mechanistic research. (Chemical Equation Presented).
