73882-45-8Relevant academic research and scientific papers
Aqueous N-methylmorpholine N-oxide as a new medium for alkylation of pyrazoles
Hasratyan, Ani H.,Alexanyan, Ashkharuhi G.,Khachatryan, Hasmik N.,Zakaryan, Geghetsik B.,Hayotsyan, Sargis S.,Danagulyan, Gevorg G.,Attaryan, Hovhannes S.
, p. 751 - 754 (2018/09/19)
[Figure not available: see fulltext.] It is shown that alkylation of pyrazoles with (E)/(Z)-1,3-dichlorobut-2-enes can be carried out in an alkaline aqueous medium in the presence of N-methylmorpholine N-oxide. In some cases, this technique may substitute
Regioselective Synthesis, NMR, and Crystallographic Analysis of N1-Substituted Pyrazoles
Huang, Adrian,Wo, Kellie,Lee, So Yeun Christine,Kneitschel, Nika,Chang, Jennifer,Zhu, Kathleen,Mello, Tatsiana,Bancroft, Laura,Norman, Natalie J.,Zheng, Shao-Liang
, p. 8864 - 8872 (2017/09/11)
A systematic study of the N-substitution reactions of 3-substituted pyrazoles under basic conditions has been undertaken. Regioselective N1-alkylation, -arylation, and -heteroarylation of 3-substituted pyrazoles have been achieved using K2CO3-DMSO. The regioselectivity is justified by the DFT calculations at the B3LYP/6-31G??(d) level. A consistent steric effect on chemical shift has been observed for N-alkyl pyrazole analogues. Twenty-five X-ray crystallographic structures have been obtained to confirm the regiochemistry of the major products.
HETEROCYCLIC MODULATORS OF LIPID SYNTHESIS AND COMBINATIONS THEREOF
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Page/Page column 336, (2015/07/07)
Heterocyclic modulators of lipid synthesis are provided as well as pharmaceutically acceptable salts thereof; pharmaceutical compositions comprising such compounds; and methods of treating conditions characterized by disregulation of a fatty acid synthase pathway by the administration of such compounds and combinations of such compounds and other therapeutic agents.
Quaternization and dequaternization of pyrazoles in solvent- free conditions: Conventional heating versus microwave irradiation
Diez-Barra, Enrique,De La Hoz, Antonio,Sanchez-Migallon, Ana,Elguero, Jose
, p. 889 - 894 (2007/10/03)
We report a study on the quaternization and dequaternization of pyrazoles by conventional heating and microwave irradiation in solvent-free conditions. Microwave irradiation produces an acceleration in the quaternization rate and a rapid equilibration between quaternized and non quaternized products. Dequaternization is also more rapid and a change on the selectivity is observed using symmetric pyrazolium salts.
Oxidation potential as a measure of the reactivity of anionic nucleophiles. Behaviour of different classes of nucleophiles
Niyazymbetov, Murat E.,Rongfeng, Zhou,Evans, Dennis H.
, p. 1957 - 1962 (2007/10/03)
Anodic peak potentials for 42 anionic nucleophiles are reported along with the rate constants for the reactions of the anions with benzyl chloride.By comparing these rate constants with those of the reactions of outer-sphere electron-transfer reagents (radical anions), it has been demonstrated that the reactions of the anions with benzyl chloride are typical single-step SN2 reactions as opposed to a two-step process comprising dissociative single electron transfer (SET) to benzyl chloride followed by radical combination.The data suggest that very electron-rich nucleophilic anions with potentials of -1.5 to -2.2 V (and more negative) with respect to the ferrocenium/ferrocene couple might participate in a SET reaction.The 42 anions studied included representatives of four classes of nucleophiles, viz. sulfur-, carbon-, oxygen- and nitrogen-centred anions.The previously observed correlation of rate constants and anodic peak potential was again found for these anions with the most reactive species having the most negative peak potentials.Correlations by class indicate that the sensitivity of rate constants to changes in peak potential is greatest (and equivalent) for the sulfur-, carbon- and oxygen-anions and for representatives with the same peak potential, the rate constants by class follow the order sulfur > carbon > oxygen.The nitrogen nucleophiles show a significantly lower sensitivity of rate constant to changes in peak potential than do the other three classes.
Activation of Exocyclic α-Positions of Azole N-Oxides by O-Silylation
Begtrup, Mikael,Vedso, Per
, p. 2555 - 2564 (2007/10/02)
Exocyclic α-positions at immonium ring carbon atoms of pyrazole and 1,2,3-triazole 1-oxides are selectively attacked in a one-pot sequence comprising silylation with iodotrimethylsilane, deprotonation with 1,2,2,6,6-pentamethylpiperidine and allylic substitution of the trimethylsilyloxy group with the iodide ions liberated by the silylation.In this way 3- and 5-iodomethylpyrazoles as well as 4-iodomethyl-1,2,3-triazoles are obtained in good yields.These may be useful for the preparation of heteroarylmethyl derivatives since the iodine atom can be displaced by even weak nucleophiles such as acetate ions.The side chain iodination is complementary to O-alkylation of the N-oxides followed by nucleophilic attack which preferentially takes place at ring carbon atoms.
Orientation de la reaction d'alkylation des pyrazoles dans des conditions neutres et en catalyse par transfert de phase
Tarrago, Georges,Ramdani, Abdelkrim,Elguero, Jose,Espada, Modesta
, p. 137 - 142 (2007/10/02)
The N-butylation and N-benzylation of nine pyrazoles bearing different substituents in positions 3 and 5 have been studied in neutral and basic medium (phase transfer catalysis).The orientation of the reaction depends strongly on the method used when the
