cas 3430-16-8, 3-Bromo-5-methylpyridine | Articles data

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A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
The kinetics of quinuclidine displacement of BH3 from a wide range of Lewis base borane adducts have been measured. Parameterization of these rates has enabled the development of a nucleofugality scale (NFB), shown to quantify and predict the leaving group ability of a range of other Lewis bases. Additivity observed across a number of series R′3-nRnX (X = P, N; R′ = aryl, alkyl) has allowed the formulation of related substituent parameters (nfPB, nfAB), providing a means of calculating NFB values for a range of Lewis bases that extends far beyond those experimentally derived. The utility of the nucleofugality parameter is explored by the correlation of the substituent parameter nfPB with the hydrolyses rates of a series of alkyl and aryl MIDA boronates under neutral conditions. This has allowed the identification of MIDA boronates with heteroatoms proximal to the reacting center, showing unusual kinetic lability or stability to hydrolysis.
Taylor, Nicholas P.,Gonzalez, Jorge A.,Nichol, Gary S.,García-Domínguez, Andrés,Leach, Andrew G.,Lloyd-Jones, Guy C.
supporting information
p. 721 - 729
(2022/01/04)

Synthesis method of 3-bromo-5-methylpyridine
The invention relates to the field of organic chemistry and particularly provides a synthesis method of 3-bromo-5-methylpyridine. The synthesis method includes the steps of: 1) performing a reaction to diethyl malonate and alkaline metal to generate a salt, and dropwise adding a toluene solution of 3-nitro-5-chloropyridine to perform a condensation reaction, and decarboxylating the product under an acidic condition to obtain 3-nitro-5-methylpyridine; 2) performing hydrogenation reduction to the 3-nitro-5-methylpyridine with Pd/C as a catalyst and methanol as a solvent, performing suction filtration and concentrating a filtrate to prepare 3-amino-5-methylpyridine; and 3) performing a reaction to the 3-amino-5-methylpyridine with an acid to generate a salt, and cooling the salt to -10 - 0 DEG C, dropwise adding liquid bromine, and then dropwise adding a sodium nitrite water solution, regulating the pH value of the solution to alkalinity and performing extraction, drying and concentration to obtain the 3-bromo-5-methylpyridine. The synthesis method is mild in reaction conditions, is high in yield, employs easy-to-obtained raw materials, is low in cost, is short in process route and has industrial prospect.
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Paragraph 0026

(2017/10/07)

Regioselectivity in free radical bromination of unsymmetrical dimethylated pyridines
During a literature review some curious inconsistencies in the free radical bromination of picolines were noted. To achieve a better understanding of the mechanisms and regioselectivity we reran these reactions, extending our work to unsymmetrical lutidin
Thapa, Rajesh,Brown, Jordan,Balestri, Thomas,Taylor, Richard T.
supporting information
p. 6743 - 6746
(2015/01/09)

NaBH4-TMEDA and a palladium catalyst as efficient regio- and chemoselective system for the hydrodehalogenation of halogenated heterocycles
The pair NaBH4-TMEDA as hydride source and a palladium catalyst in THF prove to be an efficient system for the hydrodehalogenation of halogenated heterocycles with one or more heteroatoms. In general, Pd(OAc) 2-PPh3 rapidly hydrodehalogenates reactive halo-heterocycles such as bromo-pyridines, -quinolines, -thiophenes, -indoles, -imidazoles, etc., at room temperature in very good yields, whereas in most cases PdCl2(dppf) reduces less reactive halides such as chloro-pyridines, -quinolines, -pyrimidines and bromo-indoles, -benzofurans, etc. Moreover, PdCl2(tbpf) shows to be even more active removing the 2- and 5-chlorine from both thiophene and thiazole rings. The reaction conditions tolerate various functional groups, allowing highly chemoselective reactions in the presence of halide, ester, alkyne, alkene and nitrile substituents. Moreover, with a proper selection of the catalyst it is also possible to obtain a good control in the regioselective hydrodehalogenation of a variety of polyhalogenated substrates.
Chelucci, Giorgio,Figus, Susanna
p. 191 - 209
(2014/07/21)

Meta halogenation of 1,3-disubstituted arenes via iridium-catalyzed arene borylation
We report the meta halogenation of 1,3-disubstituted arenes to form 3,5-disubstituted aryl bromides and chlorides by using iridium-catalyzed arene borylation chemistry. Iridium-catalyzed borylation of arenes with B2pin2, followed by reaction of the boronic ester with copper(II) bromide or chloride converts arylboronic esters to the corresponding aryl halides. A variety of arenes containing alkoxy, alkyl, halogen, nitrile, ester, amide, and pivaloyl and TIPS-protected alcohols were converted to the corresponding 3,5-disubstituted aryl bromides and chlorides in yields ranging from 46% to 85%. In addition, 2,6-disubstituted and 3-substituted pyridines were converted to the 4-halo and 5-halopyridines, respectively. The utility of this methodology was demonstrated by the formal conversion of nicotine to Altinicline in three steps with an overall yield of 61% using meta bromination of nicotine as the first step. Copyright
Murphy, Jaclyn M.,Liao, Xuebin,Hartwig, John F.
p. 15434 - 15435
(2008/09/19)

ANTIBACTERIAL AGENTS
Compounds of formula (I) have antibacterial activity wherein R represents hydrogen or 1, 2 or 3 optional substituents; W is =C(R1)- or =N-; R1 is hydrogen or an optional substituent and R2 is hydrogen, methyl, or fluorine; or R1 and R2 taken together are -CH2-, -CH2CH2-, -O-, or, in either orientation, -O- CH2- Or -OCH2CH2-; R3 is a radical of formula -(Alk1)m-(Z)p-(Alk2)n-Q wherein m, p and n are independently 0 or 1, provided that at least one of m, p and n is 1, Z is -O-, -S-, -S(O)-, -S(O2)-, -NH-, -N(CH3)-, -N(CH2CH3)-, -C(=O)-, -O-(C=O)-, -C(=O)-O-, or an optionally substituted divalent monocyclic carbocyclic or heterocyclic radical having 3 to 6 ring atoms; or an optionally substituted divalent bicyclic heterocyclic radical having 5 to 10 ring atoms; Alk1 and Alk2 are optionally substituted C1C6 alkylene, C2-C6 alkenylene, or C2-C6 alkynylene radicals, which may optionally terminate with or be interrupted by -O-, -S-, -S(O)-, -S(O2)-, -NH-, -N(CH3)-, or -N(CH2CH3)-; and Q is hydrogen, halogen, nitrile, or hydroxyl or an optionally substituted monocyclic carbocyclic or heterocyclic radical having 3 to 6 ring atoms; or an optionally substituted bicyclic heterocyclic radical having 5 to 10 ring atoms.
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Page/Page column 76

(2010/11/28)

PYRIDYL DERIVATIVES AND THEIR USE AS MGLU5 RECEPTOR ANTAGONISTS
The present invention is directed toward pyridyl derivatives of formula (I) as antagonists of the mGlu5 receptor. As such the compounds may be useful for treatment or prevention of disorders remedied by antagonism of the mGlu5 receptor, wherein Ar is phenyl or napthyl each of which may be substituted by one or more C1-C4 alkyl, C1-C4 alkoxy, C1-C5 acyl, halo, amino, nitro, cyano, hydroxy, C1-C5 acylamino, C1-C4 alkylsulfonylamino, mono-, di- or trifluorinated C1-C3 alkyl, substituents which may be the same or different and may bear a CONH2, CONHCH3, CON(CH3)2, CO2H, CO2CH3, OCF3, CH2NHCOCH3, CH2NH2, CH2N(CH3)2, CH2CN, CH2OH, CH2NHSO2CH3, CH2N(CH3)(CH2)2 CN, CH2N(CH3)CH(CH3)2, CH2NHCH(CH3)2, CH2NH(CH2)2CH3, CH2NHCO2R4, CH2NHCH2CH3, CH2NHCH3 NHCOC(CH3)2, or N(S(O)2CH3)2 substituent; R1 is hydrogen, halo, R4, CN, C(NOH)R3, C(NO-R4)R3, (CH)2CO2R4 , (CH2)n OR3 , COR3 , CF3,SR4 , S(O)R4, S(O)2R4, COCH2CO2R3 , NHSO2R4 , NHCOR3, C(NOR3)NH2, CH2OCOR3,(CH2)n NH2, CON(CH3)2 (CH2)nNHCO2R4 , CO2R3, CONH2, CSNH2, C(NH)NHOR3, (CH2)nN(CH3)2, or CONHNHCOR3; R2 is 1,2-ethenediyl or 1,2-ethynediyl; R3 is hydrogen or C1-C4 alkyl; R4 is C1-C4 alkyl; and n is 0, 1, 2,3 or 4; or a pharmaceutically acceptable salt thereof, or an N-oxide thereof.
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Page/Page column 25

(2008/06/13)