- Decarboxylative Ritter-Type Amination by Cooperative Iodine (I/III)─Boron Lewis Acid Catalysis
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Recent years have witnessed important progress in synthetic strategies exploiting the reactivity of carbocations via photochemical or electrochemical methods. Yet, most of the developed methods are limited in their scope to certain stabilized positions in molecules. Herein, we report a metal-free system based on the iodine (I/III) catalytic manifold, which gives access to carbenium ion intermediates also on electronically disfavored benzylic positions. The unusually high reactivity of the system stems from a complexation of iodine (III) intermediates with BF3. The synthetic utility of our decarboxylative Ritter-type amination protocol has been demonstrated by the functionalization of benzylic as well as aliphatic carboxylic acids, including late-stage modification of different pharmaceutical molecules. Notably, the amination of ketoprofen was performed on a gram scale. Detailed mechanistic investigations by kinetic analysis and control experiments suggest two mechanistic pathways.
- Narobe, Rok,Murugesan, Kathiravan,Schmid, Simon,K?nig, Burkhard
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p. 809 - 817
(2022/01/15)
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- NAMPT MODULATORS
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Provided are compounds of Formula (II) or a pharmaceutically acceptable salt thereof, wherein R1, R2, R3, R4, R5, R6, and p are as defined herein. Also provided is a pharmaceutically acceptable composition comprising a compound of Formula (II), or a pharmaceutically acceptable salt thereof. Also provided are methods of using a compound of Formula (II), or a pharmaceutically acceptable salt thereof.
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Paragraph 0313; 0314
(2021/08/13)
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- Transition-Metal- and Halogen-Free Oxidation of Benzylic sp 3 C-H Bonds to Carbonyl Groups Using Potassium Persulfate
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Aryl carbonyl compounds including acetophenones, benzophenones, imides, and benzoic acids are prepared from benzyl substrates using potassium persulfate as oxidant with catalytic pyridine in acetonitrile under mild conditions. Neither transition metals nor halogens are involved in the reactions.
- Hu, Yixin,Zhou, Lihong,Lu, Wenjun
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supporting information
p. 4007 - 4016
(2017/08/29)
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- An organocatalytic biomimetic approach to α-aminophosphonates
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A novel biomimetic approach to optically active α-aminophosphonates utilizing readily available acylphosphonates and 2-chlorobenzylamine as starting materials has been described. The enantioselective protonation constitutes the main enantiodifferentiating step in the developed strategy. This nature-inspired approach proceeds efficiently and in a highly stereoselective manner. This journal is
- Kowalczyk, Dorota,Albrecht, Lukasz
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supporting information
p. 3981 - 3984
(2015/03/30)
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- Dynamic path bifurcation in the Beckmann reaction: Support from kinetic analyses
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The reactions of oximes to amides, known as the Beckmann rearrangement, may undergo fragmentation to form carbocations + nitriles when the migrating groups have reasonable stability as cations. The reactions of oxime sulfonates of 1-substituted-phenyl-2-propanone derivatives (7-X) and related substrates (8-X, 9a-X) in aqueous CH3CN gave both rearrangement products (amides) and fragmentation products (alcohols), the ratio of which depends on the system; the reactions of 7-X gave amides predominantly, whereas 9a-X yielded alcohols as the major product. The logk-logk plots between the systems gave excellent linear correlations with slopes of near unity. The results support the occurrence of path bifurcation after the rate-determining TS of the Beckmann rearrangement/fragmentation reaction, which has previously been proposed on the basis of molecular dynamics simulations. It was concluded that path-bifurcation phenomenon could be more common than thought and that a reactivity-selectivity argument based on the traditional TS theory may not always be applicable even to a well-known textbook organic reaction.
- Yamamoto, Yutaro,Hasegawa, Hiroto,Yamataka, Hiroshi
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experimental part
p. 4652 - 4660
(2011/07/29)
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- Benzyl amide-ketoacid inhibitors of HIV-integrase
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Integrase is one of three enzymes expressed by HIV and represents a validated target for therapy. Previous reports have demonstrated that the diketoacid-based chemotype is a useful starting point for the design of inhibitors of this enzyme. In this study, one of the ketone groups is replaced by a benzylamide resulting in a new potent chemotype. A preliminary SAR study is carried out to investigate the substitution requirements on the phenyl ring and methylene group of the benzylamide.
- Walker, Michael A.,Johnson, Timothy,Naidu, B. Narasimhulu,Banville, Jacques,Remillard, Roger,Plamondon, Serge,Martel, Alain,Li, Chen,Torri, Albert,Samanta, Himadri,Lin, Zeyu,Dicker, Ira,Krystal, Mark,Meanwell, Nicholas A.
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p. 4886 - 4890
(2008/02/13)
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- 8-HETEROARYLPURINE MNK2 INHIBITORS FOR TREATING METABOLIC DISORDERS
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This invention relates to 8-Heteroarylpurine Mnk2 Inhibitors which are useful for the treatment and prevention of metabolic disorders such as obesity and diabetes.
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Page/Page column 44
(2010/11/28)
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- Anti-Helicobacter pylori agents. 4. 2-(Substituted guanidino)-4-phenylthiazoles and some structurally rigid derivatives
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In order to find a new class of anti-Helicobacter pylori (H. pylori) agents, a series of 4-[(3-acetamido)phenyl]-2-(substituted guanidino)thiazoles and some structurally rigid analoges were synthesized and evaluated for antimicrobial activity against H. pylori. Among the compounds obtained, high anti-H. pyrori activities were observed in benzyl derivative 34 (MIC = 0.025 μg/mL) and phenethyl derivatives 35 and 36 (MIC = 0.037 μg/mL and 0.017 μg/mL). Though alkyl derivatives generally showed lower activity, the 2-methoxyethyl derivative 28 preserved significant activity (MIC = 0.32 μg/mL) and also exhibited more potent gastric antisecretory activity than ranitidine. Structural restriction by bridging between the thiazole and the phenyl rings with an alkyl chain did not improve the activity in this series.
- Katsura,Tomishi,Inoue,Sakane,Matsumoto,Morinaga,Ishikawa,Takasugi
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p. 3315 - 3321
(2007/10/03)
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- A Study of Essentially Free Carbocations Derived via Diazonium and Oxo Diazonium Ions in the Liquid Phase
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Nitrogen- and nitrous oxide-separated ion pairs containing 4-substituted benzyl cations and carboxylate or tosylate anions were prepared by thermolysis of N-nitroso- and N-nitroamides, acidification of phenyldiazomethane, and nitrosation of N-benzyl-O-benzoylhydroxylamine. The cations were generated in benzene/toluene and benzene/anisole mixtures and were found to partition between the counterion and the solvent and between the aromatic cosolvent and benzene. A familial relationship among the methods was observed. As the cation became more reactive, the yield of solvent-derived products (SDPs) rose and the ratio of rate constants for its reaction with toluene versus benzene, kT/kB, fell. The yield of SDP also rose as the temperature was decreased and as N2 was replaced by N2O; however, kT/kB remained unchanged. Inert diluents had no effect on kT/kB but decreased hydrocarbon yield by 40% on 2-fold dilution. In the presence of reactive diluents that are converted into secondary alkylating agents, both the % hydrocarbon and kT/kB rose. These results are interpreted in terms of the intermediacy of inert-molecule-separated ion pairs (IMSIPs) in deamination. The cation reacted with benzoates and tosylates not only at the oxygens but also at the ipso carbon; subsequent decarboxylation and desulfonylation, respectively, led to diphenylmethanes. The ester/SDP ratio is introduced as a new measure of carbocation reactivity.
- Darbeau, Ron W.,White, Emu H.,Song, Fenhong,Darbeau, Nyla R.,Chou, James
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p. 5966 - 5978
(2007/10/03)
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- pH optimization of nucleophilic reactions in water
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We present a way of prescribing the pH for a reaction so as to obtain either (a) maximum yield in competition with hydrolysis or (b) selective reaction at either of two sites in such nucleophile-electrophile reactions as C-alkylation of acidic ketones and the acylation and sulfonylation of amines. First, we derive the following general equation for pHmax, the pH giving the highest yield of the product (P) of the reaction of a nucleophile (Nu) with a hydrolyzable electrophile (E) in water: pHmax = 1/2[log (kw/kOH) + PKw + pKw] (kw and kOH refer to the water- and hydroxide-promoted hydrolyses of E, Kw is the autoprotolysis constant of water, and Ka is the acid dissociation constant of NuH+, the conjugate acid of Nu). pHmax thus depends on a property of E (namely, kw/kOH) and a property of Nu (the pKa of NuH+), but not on the rate constant for the reaction of E with Nu or the concentration of Nu. We then deduce analogous approximate equations for maximum selectivity for reaction at either of two nucleophilic sites, specifically, equations giving pHxmax and pHymax, the pH values for the maximum yields of the respective products (Px and Py) of the reactions of E with the two nucleophiles. We find that (a) pH-yield profiles calculated from the equations concur with observed yields for reactions under pseudo-first-order conditions and (b) preparative experiments at the estimated pH values give good to excellent yields of clean products and high selectivity in both the C-alkylation and Schotten-Baumann reactions.
- King,Rathore,Lam,Guo,Klassen
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p. 3028 - 3033
(2007/10/02)
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- AROMATIC HYDROXYLATION OF BENZYLAMIDES BY POTASSIUM SUPEROXIDE
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N-benzylamides react with potassium superoxide in benzene in presence of 18-crown-6 ether to give ortho and para hydroxylated products.A mechanism is proposed for this reaction, involving the nucleophilic attack of superoxide anion to amide carbonyl and hydrogen abstraction from benzyle methylene by the substrate-superoxide adduct.
- Galliani, Guido,Rindone, Bruno
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p. 2313 - 2318
(2007/10/02)
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