23002-61-1Relevant academic research and scientific papers
Nickel-Catalyzed Negishi-Type Arylation of Trialkylsulfonium Salts
Minami, Hiroko,Nogi, Keisuke,Yorimitsu, Hideki
supporting information, p. 1542 - 1546 (2021/09/06)
Negishi-type arylation of trialkylsulfonium salts with arylzinc reagents has been accomplished under nickel catalysis. The use of cyclohexanethiol as an additional ligand was found to be particularly important to promote C-S cleavage. The present reaction accommodates one-pot arylation of dialkyl sulfides by combining with S -methylation with MeOTf. Mechanistic experiments suggest that C-S cleavage would proceed via single-electron transfer (SET) to generate the most stable carbon-centered radical and that the thiolate ligand would promote the C-S cleavage and radical recombination step.
Modular radical cross-coupling with sulfones enables access to sp3-rich (fluoro)alkylated scaffolds
Merchant, Rohan R.,Edwards, Jacob T.,Qin, Tian,Kruszyk, Monika M.,Bi, Cheng,Che, Guanda,Bao, Deng-Hui,Qiao, Wenhua,Sun, Lijie,Collins, Michael R.,Fadeyi, Olugbeminiyi O.,Gallego, Gary M.,Mousseau, James J.,Nuhant, Philippe,Baran, Phil S.
, p. 75 - 80 (2018/02/28)
Cross-coupling chemistry is widely applied to carbon-carbon bond formation in the synthesis of medicines, agrochemicals, and other functional materials. Recently, single-electron-induced variants of this reaction class have proven particularly useful in the formation of C(sp2)-C(sp3) linkages, although certain compound classes have remained a challenge. Here, we report the use of sulfones to activate the alkyl coupling partner in nickel-catalyzed radical cross-coupling with aryl zinc reagents. This method's tolerance of fluoroalkyl substituents proved particularly advantageous for the streamlined preparation of pharmaceutically oriented fluorinated scaffolds that previously required multiple steps, toxic reagents, and nonmodular retrosynthetic blueprints. Five specific sulfone reagents facilitate the rapid assembly of a vast set of compounds, many of which contain challenging fluorination patterns.
A mild and ligand-free Ni-catalyzed silylation via C-OMe cleavage
Zarate, Cayetana,Nakajima, Masaki,Martin, Ruben
supporting information, p. 1191 - 1197 (2017/05/16)
Metal-catalyzed transformations that forge carbon-heteroatom bonds are of central importance in organic synthesis. Despite the formidable potential of aryl methyl ethers as coupling partners, the scarcity of metal-catalyzed C-heteroatom bond formations via C-OMe cleavage is striking, with isolated precedents requiring specialized, yet expensive, ligands, high temperatures, and π-extended backbones. We report an unprecedented catalytic ipso-silylation of aryl methyl ethers under mild conditions and without recourse to external ligands. The method is distinguished by its wide scope, which includes the use of benzyl methyl ethers, vinyl methyl ethers, and unbiased anisóle derivatives, thus representing a significant step forward for designing new C-heteroatom bond formations via C-OMe scission. Applications of this transformation in orthogonal silylation techniques as well as in further derivatizations are also described. Preliminary mechanistic experiments suggest the intermediacy of Ni(0)-ate complexes, leaving some doubt that a canonical catalytic cycle consisting of an initial oxidative addition of the C-OMe bond to Ni(0) species comes into play.
Ni-Catalyzed Carboxylation of Unactivated Alkyl Chlorides with CO2
B?rjesson, Marino,Moragas, Toni,Martin, Ruben
supporting information, p. 7504 - 7507 (2016/07/06)
A catalytic carboxylation of unactivated primary, secondary, and tertiary alkyl chlorides with CO2 at atmospheric pressure is described. This protocol represents the first intermolecular cross-electrophile coupling of unactivated alkyl chlorides, thus leading to new knowledge in the cross-coupling arena.
Asymmetric hydrogenation of α-primary and secondary amino ketones: Efficient asymmetric syntheses of (-)-arbutamine and (-)-denopamine
Shang, Gao,Liu, Duan,Allen, Scott E.,Yang, Qin,Zhang, Xumu
, p. 7780 - 7784 (2008/04/03)
Two ss-receptor agonists (-)-denopamine and (-)-arbutamine were prepared in good yields and enantioselectivities by asymmetric hydrogenation of unprotected amino ketones for the first time by using Rh catalysts bearing electron-donating phosphine ligands. A series of α-primary and secondary amino ketones were synthesized and hydrogenated to produce various 1,2-amino alcohols in good yields and with good enantioselectivies. This Rh electron-donating phosphine-catalyzed asymmetric hyderogenation repI resents one of the most promising and convenient approaches towards the asymmetric synthesis of chiral amino alcohols.
Search for histamine H3 receptor antagonists with combined inhibitory potency at Nτ-methyltransferase: Ether derivatives
Apelt,Grassmann,Ligneau,Pertz,Ganellin,Arrang,Schwartz,Schunack,Stark, Holger
, p. 97 - 106 (2007/10/03)
With the recent development of new hybrid compounds having histamine H 3 receptor antagonist with combined histamine Nτ- methyltransferase (HMT) inhibitory potency an innovative approach was described in the research of novel lead compounds modulating histaminergic neurotransmission. Several compounds containing an ether moiety derived from the recently published 4-(3-piperidinopropoxy)phenylaminoquinoline derivatives (like FUB 836), were synthesized in this study and tested for their affinity at cloned human histamine H3 (hH3) receptors and on the inhibition of rat HMT. Besides different heterocycles, e.g. nitro- or amino-substituted pyridines, quinolines, benzothiazole or pyrroline, three classes of compounds were produced: heteroaromatic 3-piperidinopropyl ethers, keto- or imino-substituted 4-(3-piperidinopropyl)phenyl ethers and 4-(3-piperidinopropyl)phenyl ethers with substituted (alkyl)aminopyridines. Whereas the (3-piperidinopropoxy)heterocycles showed only moderate activities on both test models, the 4-(3-piperidinopropoxy)phenyl derivatives were identified as potent histamine H3 receptor ligands and/or HMT inhibitors. Ki values up to 0.42 nM were found for the affinity to the hH 3 receptor. HMT inhibitory potency was identified with IC 50 values about 0.3 μM for the most potent compounds in this series. Comparison of the pyridine-containing derivatives to recently published quinoline analogues showed a decrease in potencies for the pyridines. The dual activity, H3 receptor affinity and HMT inhibition, was moderate to good. For all compounds affinities at hH3 receptors were higher than their inhibitory HMT potencies. The described new histamine H3 receptor antagonists with an ether moiety represent a further promising step in our investigations for a dual activity.
Method for producing 1-substituted-1,2,3- triazole derivative
-
, (2008/06/13)
A method for producing a compound of the formula: (1) in a secondary or tertiary alcohol in the presence of a base, or (2) in the absence of a base is provided. According to this method, a 1-substituted-1,2,3-triazole compound having a tyrosine kinase inhibitory action can be produced efficiently in a high yield at an industrial large scale by a convenient method
Development of a new class of nonimidazole histamine H3 receptor ligands with combined inhibitory histamine N-methyltransferase activity
Apelt, Joachim,Ligneau, Xavier,Pertz, Heinz H.,Arrang, Jean-Michel,Ganellin, C. Robin,Schwartz, Jean-Charles,Schunack, Walter,Stark, Holger
, p. 1128 - 1141 (2007/10/03)
In search of novel ways to enhance histaminergic neurotransmission in the central nervous system, a new class of nonimidazole histamine H3 receptor ligands were developed that simultaneously possess strong inhibitory activity on the main histamine metabolizing enzyme, histamine N-methyltransferase (HMT). The novel compounds contain an aminoquinoline moiety, which is an important structural feature for HMT inhibitory activity, connected by different spacers to a piperidino group (for H3 receptor antagonism). Variation of the spacer structure provides two different series of compounds. One series, having only an alkylene spacer between the basic centers, led to highly potent HMT inhibitors with moderate to high affinity at human histamine H3 receptors. The second series possesses a p-phenoxypropyl spacer, which may be extended by another alkylene chain. This latter series also showed strong inhibitory activity on HMT, and in most cases, the H3 receptor affinity even surpassed that of the first series. One of the most potent compounds with this dual mode of action is 4-(4-(3-piperidinopropoxy)phenylamino)quinoline (34) (hH3, Ki = 0.09 nM; HMT, IC50 = 51 nM). This class of compounds showed high antagonist potency and good H3 receptor selectivity in functional assays in guinea pig on H1, H2, and H3 receptors. Because of low or missing in vivo activity of two selected compounds, the proof of concept of these valuable pharmacological tools for the supposed superior overall enhancing effect on histaminergic neurotransmission failed to appear hitherto.
Structure of ω-Arylalkyl Radicals: A 13C CIDNP Investigation
Olah, George A.,Krishnamurthy, V. V.,Singh, Brij P.,Iyer, Pradeep S.
, p. 955 - 963 (2007/10/02)
Thermolysis of a series of ω-arylalkanoyl m-chlorobenzoyl (and acetyl) peroxides at ca. 100 deg C in cyclohexanone and in hexachloroacetone was studied by using 13C chemically induced dynamic nuclear polarization.Analysis of the observed 13C polarizations indicate that all the three radicals (β-arylethyl, γ-arylpropyl and δ-arylbutyl) have open-chain structures with no evidence for aryl participation resulting in spirocycloalkylcyclohexadienyl radicals.
