6668-39-9Relevant academic research and scientific papers
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.
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.
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).
Easy Access to 1-Amino and 1-Carbon Substituted Isoquinolines via Cobalt-Catalyzed C - H/N - O Bond Activation
Muralirajan, Krishnamoorthy,Kuppusamy, Ramajayam,Prakash, Sekar,Cheng, Chien-Hong
supporting information, p. 774 - 783 (2016/03/09)
A green atom-economical method for the synthesis of highly functionalized 1-amino and 1-carbon substituted isoquinolines from the reaction of N′-hydroxybenzimidamides and aryl ketoximes, respectively, with alkynes via pentamethylcyclopentadienylcobalt(III)-catalyzed C - H/N - O bond activation is described. The external oxidant-free annulation reaction uses the =NOH moiety in N′-hydroxybenzimidamides or N-aromatic ketone oximes as the directing group and internal oxidant. This first row transition metal-catalyzed annulation serves as an efficient alternative for the synthesis of isoquinolines, as water is the only by-product and expensive noble metals such as rhodium(III), iridium(III), palladium(II), and ruthenium(II) are not required. The reaction proceeds via C - H activation, alkyne insertion, reductive elimination, and N - O activation.
Synthesis of Air- and Moisture-Stable, Storable Chiral Oxorhenium Complexes and Their Application as Catalysts for the Enantioselective Imine Reduction
Das, Braja Gopal,Nallagonda, Rajender,Dey, Dhananjay,Ghorai, Prasanta
supporting information, p. 12601 - 12605 (2015/09/01)
Air-/moisture-stable, crystalline, and storable chiral salicyloxazoline based oxorhenium(V) complexes have been synthesized and their catalytic application for the asymmetric reduction of ketimines using hydrosilane as hydride source is disclosed. A broad substrate scope, high yields, and excellent enantioselectivities (up to 99 %) are attained. Furthermore, the syntheses of enantiopure α-amino esters, γ- and δ-lactams, and isoindolinones have also been carried out using this methodology. Finally, the method has been applied to synthetic targets of pharmaceutical relevance, such as R-(+)-salsolidine and R-(+)-crispine A.
APPLICATIONS OF N6-SUBSTITUTED ADENOSINE DERIVATIVE AND N6-SUBSTITUTED ADENINE DERIVATIVE TO CALMING, HYPNOSES, CONVULSION RESISTANCE, EPILEPTIC RESISTANCE, PARKINSON DISEASE RESISTANCE, AND DEMENTIA PREVENTION AND TREATMENT
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Paragraph 0184, (2018/10/27)
PROBLEM TO BE SOLVED: To prepare analgesics, hypnotic agents, anticonvulsant agents, antiepileptics, antiparkinson drugs, dementia prophylactics, and health care food. SOLUTION: The present invention relates to an N6-substituted adenosine derivative and an N6-substituted adenine derivative selected from the group consisting of specific compounds. The present invention also relates to a pharmaceutical composition at least comprising a therapeutically effective amount of the compounds and a pharmaceutically acceptable carrier. The invention further relates to the compounds used in preparation of analgesics, hypnotic agents, anticonvulsant agents, antiepileptics, antiparkinson drugs, dementia prophylactics, and health care food. COPYRIGHT: (C)2016,JPO&INPIT
N6-SUBSTITUTED ADENOSINE DERIVATIVES AND N6-SUBSTITUTED ADENINE DERIVATIVES AND USES THEREOF
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Paragraph 0366, (2013/03/26)
The present invention provides N6-substituted adenosine derivatives and N6-substituted adenine derivatives, manufacturing methods thereof, a pharmaceutical composition comprising the said compounds above, and uses of these compounds in manufacturing medicaments and health-care products for treating insomnia, convulsion, epilepsy, and Parkinson's diseases, and preventing and treating dementia.
