35854-44-5Relevant academic research and scientific papers
Acylation of 2-benzylpyridine N-oxides and subsequent in situ [3,3]-sigamatropic rearrangement reaction
Antilla, Jon C.,Jing, Hua-qing,Li, Hong-liang
, (2020/09/22)
An effective method for the acylation of 2-benzylpyridine N-oxides and their fast in situ [3,3]-sigmatropic rearrangement was reported. This transformation has a wide substrate scope under mild conditions, giving moderate to excellent yields. The application for the synthesis of chiral phenyl-2-pyridylmethanol products was briefly explored. Furthermore, an interesting example of tandem substitution and in situ [3,3]-sigamatropic rearrangement of 2-benzylpyridine N-oxide with benzenecarboximidoyl chloride was reported.
Metal-Free Halogen(I) Catalysts for the Oxidation of Aryl(heteroaryl)methanes to Ketones or Esters: Selectivity Control by Halogen Bonding
Guha, Somraj,Sekar, Govindasamy
supporting information, p. 14171 - 14182 (2018/09/10)
Metal-free halogen(I) catalysts were used for the selective oxidation of aryl(heteroaryl)methanes [C(sp3)?H] to ketones [C(sp2)=O] or esters [C(sp3)?O]. The synthesis of ketones was performed with a catalytic amount of NBS in DMSO solvent. Experimental studies and density functional theory (DFT) calculations supported the formation of halogen bonding (XB) between the heteroarene and N-bromosuccinimide, which enabled imine–enamine tautomerism of the substrates. No additional activator was required for this crucial step. Isotope-labeling and other supporting experiments suggested that a Kornblum-type oxidation with DMSO and aerobic oxygenation with molecular oxygen took place simultaneously. A background XB-assisted electron transfer between the heteroarenes and halogen(I) catalysts was responsible for the formation of heterobenzylic radicals and, thus, the aerobic oxygenation. For selective acyloxylation (ester formation), a catalytic amount of iodine was employed with tert-butyl hydroperoxide in aliphatic carboxylic acid solvent. Several control reactions, spectroscopic studies, and Time-Dependent Density Functional Theory (TD–DFT) calculations established the presence of acetyl hypoiodite as an active halogen(I) species in the acetoxylation process. With the help of a selectivity study, for the first time we report that the strength of the XB interaction and the frontier orbital mixing between the substrates and acyl hypoiodites determined the extent of the background electron-transfer process and, thus, the selectivity of the reaction.
Copper-Catalyzed Base-Controlled Diastereoselective Synthesis of Tetraarylethanes from 2-Benzylpyridines
Chandrasekar, Selvaraj,Karthikeyan, Iyyanar,Sekar, Govindasamy
, p. 1275 - 1283 (2017/12/26)
A highly efficient and base-controlled diastereoselective synthesis of tetraarylethanes through copper-catalyzed dehydrogenative homocoupling of readily available 2-benzylpyridines is reported. Various dl - and meso -tetraarylethanes were diastereoseletively synthesized by this new protocol, where base plays the role of the principle modulator: Grignard reagents selectively provide the C2 isomers, whereas KO t -Bu promotes the formation of the meso -tetraarylethanes. Interestingly, the presence of excess KO t -Bu generates the (E)-tetraarylethenes as the only product.
Nickel-Catalyzed Hydrogenolysis and Conjugate Addition of 2-(Hydroxymethyl)pyridines via Organozinc Intermediates
Hanna, Luke E.,Harris, Michael R.,Domon, Kenji,Jarvo, Elizabeth R.
, p. 6304 - 6307 (2017/12/08)
2-Hydroxymethylpyridines undergo nickel-catalyzed hydrogenolysis upon activation with a chlorophosphate. Reactions employ diethylzinc and are proposed to proceed through secondary benzylzinc reagents. Quenching with deuteromethanol provides straightforward incorporation of a deuterium label in the benzylic position. Intramolecular conjugate additions with α,β-unsaturated esters are also demonstrated and support the intermediacy of a benzylzinc complex.
Triazole Ureas Act as Diacylglycerol Lipase Inhibitors and Prevent Fasting-Induced Refeeding
Deng, Hui,Kooijman, Sander,Van Den Nieuwendijk, Adrianus M. C. H.,Ogasawara, Daisuke,Van der Wel, Tom,Van Dalen, Floris,Baggelaar, Marc P.,Janssen, Freek J.,Van Den Berg, Richard J. B. H. N.,Den Dulk, Hans,Cravatt, Benjamin F.,Overkleeft, Herman S.,Rensen, Patrick C. N.,Van der Stelt, Mario
supporting information, p. 428 - 440 (2017/04/26)
Triazole ureas constitute a versatile class of irreversible inhibitors that target serine hydrolases in both cells and animal models. We have previously reported that triazole ureas can act as selective and CNS-active inhibitors for diacylglycerol lipases (DAGLs), enzymes responsible for the biosynthesis of 2-arachidonoylglycerol (2-AG) that activates cannabinoid CB1 receptor. Here, we report the enantio- and diastereoselective synthesis and structure-activity relationship studies. We found that 2,4-substituted triazole ureas with a biphenylmethanol group provided the most optimal scaffold. Introduction of a chiral ether substituent on the 5-position of the piperidine ring provided ultrapotent inhibitor 38 (DH376) with picomolar activity. Compound 38 temporarily reduces fasting-induced refeeding of mice, thereby emulating the effect of cannabinoid CB1-receptor inverse agonists. This was mirrored by 39 (DO34) but also by the negative control compound 40 (DO53) (which does not inhibit DAGL), which indicates the triazole ureas may affect the energy balance in mice through multiple molecular targets.
Versatile C(sp2)?C(sp3) Ligand Couplings of Sulfoxides for the Enantioselective Synthesis of Diarylalkanes
Dean, William M.,?iau?iulis, Mindaugas,Storr, Thomas E.,Lewis, William,Stockman, Robert A.
, p. 10013 - 10016 (2016/08/16)
The reaction of chiral (hetero)aryl benzyl sulfoxides with Grignard reagents affords enantiomerically pure diarylalkanes in up to 98 % yield and greater than 99.5 % enantiomeric excess. This ligand coupling reaction is tolerant to multiple substitution patterns and provides access to diverse areas of chemical space in three operationally simple steps from commercially available reagents. This strategy provides orthogonal access to electron-deficient heteroaromatic compounds, which are traditionally synthesized by transition metal catalyzed cross-couplings, and circumvents common issues associated with proto-demetalation and β-hydride elimination.
Synergistic H4NI-AcOH Catalyzed Oxidation of the Csp3-H Bonds of Benzylpyridines with Molecular Oxygen
Ren, Lanhui,Wang, Lianyue,Lv, Ying,Li, Guosong,Gao, Shuang
supporting information, p. 2078 - 2081 (2015/05/13)
The oxidation of benzylpyridines forming benzoylpyridines was achieved based on a synergistic H4NI-AcOH catalyst and molecular oxygen in high yield under solvent-free conditions. This is the first nonmetallic catalytic system for this oxidation transformation using molecular oxygen as the oxidant. The catalytic system has a wide scope of substrates and excellent chemoselectivity, and this procedure can also be scaled up. The study of a preliminary reaction mechanism demonstrated that the oxidation of the Csp3-H bonds of benzylpyridines was promoted by the pyridinium salts formed by AcOH and benzylpyridines. The synergistic effect of H4NI-AcOH was also demonstrated by control experiments. (Figure Presented).
Synthesis of heteroaryl compounds through cross-coupling reaction of aryl bromides or benzyl halides with thienyl and pyridyl aluminum reagents
Chen, Xu,Zhou, Lingmin,Li, Yimei,Xie, Tao,Zhou, Shuangliu
, p. 230 - 239 (2014/01/17)
An efficient method for synthesis of useful biaryl building blocks containing 2-thienyl, 3-thienyl, 2-pyridyl, and 3-pyridyl moieties was provided through cross-coupling reactions of aryl bromides or benzyl halides with heteroaryl aluminum reagents in the presence of Pd(OAc)2 and (o-tolyl)3P. The coupling reaction also worked efficiently with heteroaryl bromides affording series of heterobiaryl compounds. The reaction of phenylbromide with in situ prepared 3-pyridyl aluminum was demonstrated to afford the product 8a in high yield. Additionally, the catalytic system was also suited well for the coupling reaction of benzyl halides with pyridyl aluminum reagents to afford series of pyridyl-arylmethane.
Facile preparation of highly-functionalized, nitrogen-bearing diarylmethanes
Schmink, Jason R.,Tudge, Matthew T.
, p. 15 - 20 (2013/02/21)
A palladium-catalyzed cross coupling of nitrogen bearing heterocyclic chloromethyl derivatives with aryl and heteroaryl boronic acids has been developed. In almost all cases, highly efficient cross-couplings were observed at ambient temperature, mitigating unwanted thermally induced side-reactions. The comprehensive substrate scope and respectable yields highlight the synthetic utility of this reaction.
Synthesis of aryl(di)azinyl ketones through copper- and iron-catalyzed oxidation of the methylene group of aryl(di)azinylmethanes
De Houwer, Johan,Abbaspour Tehrani, Kourosch,Maes, Bert U. W.
supporting information; experimental part, p. 2745 - 2748 (2012/04/10)
Sustainable Oxidations: An oxidation method to transform aryl(di)azinylmethanes into aryl(di)azinyl ketones is described. Base metals (copper and iron) as catalysts in combination with O2 as the oxidant are used, which makes this method sustainable. The utility of this method is illustrated by the synthesis of 6-(4-methylbenzoyl)pyridine-2-carbaldehyde, which is an intermediate in the preparation of the drug Acrivastine. Copyright
