A new efficient synthesis of pyrazoles from hydrazonoyl halides and β-oxophosphonates
A new practical and efficient synthesis of 1,3,5-trisubstituted pyrazoles has been developed by reacting of hydrazonoyl halides with β- oxophosphonates under mild conditions in good yields with excellent regioselectivity. This process employs an addition-elimination sequence. Wide scope, functional group compatibility has been established.
Rate enhancement of 1,3-dipolar cycloaddition of N-methylindole: The singular role of Grignard reagents
The reactions of 2-N-methylindolyl and 2- and 3-benzo [b]thiophenyl anions with nitrile oxides and nitrilimines were performed in order to investigate whether the use of anionic dipolarophiles modifies a classical 1,3-dipolar cycloaddition. When lithium compounds were used as bases, the heterocyclic anions invariably acted as nucleophilic species; in contrast, when a Grignard reagent was employed, the N-methylindole gave cycloaddition products with an extraordinary rate enhancement. The hypothesis that N-methylindole and ethylmagnesium bromide give an adduct much more reactive than N-methylindole itself was supported by the results of a theoretical investigation. The structure and electron distribution of the adduct were determined by ab initio calculations and compared with those of known Grignard complexes with nitrogen ligands. The performance of different basis sets was tested. The quantum theory of atoms in molecules was used to determine atomic charges and to describe the nature of bonds in terms of the properties of the electron density at the bond critical points.
Benincori, Tiziana,Sannicolo, Franco,Trimarco, Licia,Bonati, Laura,Grandi, Stefania,Pitea, Demetrio,Gatti, Carlo
p. 455 - 466
(2007/10/03)
α,β-UNSATURATED THIOLATES AND THEIR ANALOGS IN CYCLOADDITION REACTIONS. XVIII. REACTION OF 2-PHENYLETHYNYLTELLUROLATES WITH C-ETHOXYCARBONYL-N-PHENYLNITRILIMINE
The reaction of sodium or lithium 2-phenylethynyltellurolates with C-ethoxycarbonyl-N-phenylnitrilimine leads to the oxidation product of ethynyltellurolate - di(2-phenylethynyl)telluride, a product of reduction of the initial nitrilimine - the phenylhydr
Petrov, M. L.,Terent'eva, N. A.,Potekhin, K. A.,Struchkov, Yu. T.
p. 1137 - 1142
(2007/10/02)
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