1851-22-5Relevant articles and documents
A Journey through Hemetsberger–Knittel, Leimgruber–Batcho and Bartoli Reactions: Access to Several Hydroxy 5- and 6-Azaindoles
Radix, Sylvie,Hallé, Fran?ois,Mahiout, Zahia,Teissonnière, Amélie,Bouchez, Grégoire,Auberger, Ludovic,Barret, Roland,Lomberget, Thierry
, (2022/02/22)
The preparation of various 5- and 6-azaindoles, heterocyclic structures that are frequently part of molecules in clinical development, and their monohydroxy analogues were described. Different strategies, relying on the de novo pyrrole ring formation, were investigated and, thanks to Hemetsberger–Knittel, Bartoli and Leimgruber–Batcho approaches, 4- and 7-monohydroxy 5- and 6-azaindoles were obtained. The crucial introduction of the oxygen atom was carried out from halogen derivatives, using nucleophilic substitution reactions under basic conditions with or without a copper catalyst. Some preliminary oxidation reactions have shown that it was yet not possible to synthesize the azaquinone indole structure from monohydroxy azaindole, using molecular oxygen in the presence of salcomine as a catalyst.
Visible-Light-Induced ortho-Selective Migration on Pyridyl Ring: Trifluoromethylative Pyridylation of Unactivated Alkenes
Jeon, Jinwon,He, Yu-Tao,Shin, Sanghoon,Hong, Sungwoo
supporting information, p. 281 - 285 (2019/11/26)
The photocatalyzed ortho-selective migration on a pyridyl ring has been achieved for the site-selective trifluoromethylative pyridylation of unactivated alkenes. The overall process is initiated by the selective addition of a CF3 radical to the alkene to provide a nucleophilic alkyl radical intermediate, which enables an intramolecular endo addition exclusively to the ortho-position of the pyridinium salt. Both secondary and tertiary alkyl radicals are well-suited for addition to the C2-position of pyridinium salts to ultimately provide synthetically valuable C2-fluoroalkyl functionalized pyridines. Moreover, the method was successfully applied to the reaction with P-centered radicals. The utility of this transformation was further demonstrated by the late-stage functionalization of complex bioactive molecules.
Strategic Approach on N-Oxides in Gold Catalysis – A Case Study
Schie?l, Jasmin,Stein, Philipp M.,Stirn, Judith,Emler, Kirsten,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
supporting information, p. 725 - 738 (2018/10/20)
An extensive kinetic study of selected key reactions of (oxidative) gold catalysis concentrates on the decrease of the catalytic activity due to inhibition of the gold(I) catalyst caused by pyridine derivatives that are obtained as by-products if N-oxides are applied as oxygen donors. The choice of the examined pyridine derivatives and their corresponding N-oxides has been made regardless of their commercial availability; particular attention has been paid to the practical benefit which up to now has been neglected in most of the reaction screenings. The test reactions were monitored by GC and 1H NMR spectroscopy. The received reaction constants provide information concerning a correlation between the electronic structure of the heterocycle and the catalytic activity. Based on the collected kinetic data, it was possible to develop a basic set of three N-oxides which have to be taken into account in further oxidative gold(I)-catalyzed reactions. (Figure presented.).
Synthesis method of heterocyclic compound 3-methoxypyridine
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Paragraph 0025, (2017/08/17)
The invention discloses a synthesis method of a heterocyclic compound 3-methoxypyridine. The method comprises the following steps: putting raw materials, i.e., 3-halogenated pyridine, hydrogen peroxide and acetic acid into a three-mouth flask, carrying out reaction for 4-8h at the temperature of 40-80 DEG C under the condition of stirring, recovering the acetic acid, adding a saturated sodium carbonate solution and stirring to enable a system to be alkaline, evaporating to remove water, then adding chloroform for washing, and carrying out vacuum distillation to obtain N-oxide-3-halogenated pyridine; respectively adding the N-oxide-3-halogenated pyridine, metal salt of alkyl alcohol, a catalyst A and alcohol into the three-mouth flask, carrying out reflux reaction for 5-8h under the condition of stirring, then cooling, neutralizing a product to be neutral, and carrying out distillation to obtain N-oxide-3-alkyloxypyridine; respectively adding the N-oxide-3-alkyloxypyridine, ferric trichloride, hydrazine hydrate, activated carbon and ethanol into the three-mouth flask, carrying out reaction at the temperature of 70 DEG C for 3h, cooling to room temperature, and carrying out vacuum distillation to obtain the 3-methoxypyridine. The synthesis method is high in intermediate conversion rate, mild in reaction conditions, safe in operation, low in price of raw materials and easy in raw material obtaining, thus being suitable for industrial production.
Regioselective Three-Component Reaction of Pyridine N-Oxides, Acyl Chlorides, and Cyclic Ethers
Jones, D. Heulyn,Kay, Steven T.,McLellan, Jayde A.,Kennedy, Alan R.,Tomkinson, Nicholas C. O.
supporting information, p. 3512 - 3515 (2017/07/17)
A novel three-component reaction of pyridine N-oxides, acyl chlorides, and cyclic ethers is described. Treatment of an electron-deficient pyridine N-oxide with an acyl chloride in the presence of a cyclic ether at 25-50 °C leads to a substituted pyridine as a single regioisomer in up to 58% isolated yield. Isotopic-labeling experiments and substrate scope support the reaction proceeding through a carbene intermediate.
A lipase-glucose oxidase system for the efficient oxidation of: N -heteroaromatic compounds and tertiary amines
Yang, Fengjuan,Zhang, Xiaowen,Li, Fengxi,Wang, Zhi,Wang, Lei
supporting information, p. 3518 - 3521 (2016/07/06)
In this work, a lipase-glucose oxidase system has been designed and proven to be an efficient system for the oxidation of N-heteroaromatic compounds and tertiary amines. This dual-enzyme system not only displays environmental friendliness, but also demonstrates its huge potential in industrial applications.
The microwave-assisted ortho-alkylation of azine N-oxides with N-tosylhydrazones catalyzed by copper(i) iodide
Jha, Abadh Kishor,Jain, Nidhi
supporting information, p. 1831 - 1834 (2016/02/05)
A copper catalyzed regioselective cross-coupling of N-tosylhydrazones with azine N-oxides to yield ortho-alkylated products in moderate to good yields is reported. The reaction is facilitated by microwave, takes place without any ligand, and uses inexpensive copper(i) iodide as the catalyst.
2, 3-dichloro polypyridine manufacturing method
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Paragraph 0030-0032, (2016/12/07)
PROBLEM TO BE SOLVED: To provide a new method for producing 2,3-dichloropyridine in high selectivity. SOLUTION: The method for producing 2,3-dichloropyridine comprises a step (1) to react 3-chloropyridine-N-oxide with an acylation agent expressed by RCOCl (acid chloride) or R(CO)O(CO)R (carbonate) (wherein R is 1C-12C alkyl or 6C-20C aryl) and a step (2) to react a compound of formula (2) (wherein R is same as defined above) obtained by the step (1) with a chlorinating agent. COPYRIGHT: (C)2013,JPOandINPIT
SULFONAMIDES AS TRPM8 MODULATORS
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Page/Page column 89, (2012/07/31)
Disclosed are compounds, compositions and methods for treating various diseases, syndromes, conditions and disorders, including pain. Such compounds are represented by Formula I as follows: wherein A, B, G, Y, R1, R2, R3, and R4 are defined herein.
SULFONAMIDES AS TRPM8 MODULATORS
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Page/Page column 215, (2009/03/07)
ABSTRACT Disclosed are compounds, compositions and methods for treating various diseases, syndromes, conditions and disorders, including pain. Such compounds are represented by Formula (I) as follows: wherein A, B, G, Y, R1, R2, R3 and R4 are defined herein
