18294-87-6Relevant academic research and scientific papers
A comparative LSER study of the reactivity of 2-substituted cyclohex- 1-eneacetic and 2-substituted phenylacetic acids with diazodiphenylmethane in various solvents
Nikolic,Uscumlic,Juranic, Ivan O.
, p. 613 - 622 (2009)
The rate constants for the reaction of 2-substituted cyclohex-1-eneacetic and 2- substituted phenylacetic acids with diazodiphenylmethane were determined in various aprotic solvents at 30°C. To explain the kinetic results through solvent effects, the second-order rate constants of the examined acids were correlated using the Kamlet-Taft solvatochromic equation. The correlations of the kinetic data were carried out by means of multiple linear regression analysis, and the solvent effects on the reaction rates were analyzed in terms of initial and transition state contributions. The opposite signs of the electrophilic and the nucleophilic parameters are in agreement with the well-known mechanism of the reaction of carboxylic acids with diazodiphenylmethane. The quantitative relationship between the molecular structure and the chemical reactivity is discussed, as well as the effect of the molecular geometry on the reactivity of the examined compounds.
Chemoselective γ-Oxidation of β,γ-Unsaturated Amides with TEMPO
Heindl, Sebastian,Lemmerer, Miran,Malzer, Nicolas,Matyasovsky, Ján,Maulide, Nuno,Riomet, Margaux
, p. 19123 - 19127 (2021/07/26)
A chemoselective and robust protocol for the γ-oxidation of β,γ-unsaturated amides is reported. In this method, electrophilic amide activation, in a rare application to unsaturated amides, enables a regioselective reaction with TEMPO resulting in the title products. Radical cyclisation reactions and oxidation of the synthesised products highlight the synthetic utility of the products obtained.
EtAlCl2/2,6-Disubstituted Pyridine-Mediated Carboxylation of Alkenes with Carbon Dioxide
Tanaka, Shinya,Watanabe, Kota,Tanaka, Yuuki,Hattori, Tetsutaro
supporting information, p. 2576 - 2579 (2016/06/15)
α-Arylalkenes and trialkyl-substituted alkenes undergo carboxylation with CO2 in the presence of EtAlCl2 and 2,6-dibromopyridine to afford the corresponding α,β- and/or β,γ-unsaturated carboxylic acids. This reaction is suggested to proceed via the electrophilic substitution of EtAlCl2 with the aid of the base, followed by the carbonation of the resulting ate complex. This reaction can be applied to terminal dialkylalkenes by using a mixture of 2,6-di-tert-butylpyridine and 2,6-dibromopyridine.
Conformation-based restrictions and scaffold replacements in the design of hepatitis C virus polymerase inhibitors: Discovery of deleobuvir (BI 207127)
LaPlante, Steven R.,B?s, Michael,Brochu, Christian,Chabot, Catherine,Coulombe, René,Gillard, James R.,Jakalian, Araz,Poirier, Martin,Rancourt, Jean,Stammers, Timothy,Thavonekham, Bounkham,Beaulieu, Pierre L.,Kukolj, George,Tsantrizos, Youla S.
supporting information, p. 1845 - 1854 (2014/04/03)
Conformational restrictions of flexible torsion angles were used to guide the identification of new chemotypes of HCV NS5B inhibitors. Sites for rigidification were based on an acquired conformational understanding of compound binding requirements and the roles of substituents in the free and bound states. Chemical bioisosteres of amide bonds were explored to improve cell-based potency. Examples are shown, including the design concept that led to the discovery of the phase III clinical candidate deleobuvir (BI 207127). The structure-based strategies employed have general utility in drug design.
Solvent and structural effects on the activation parameters of the reaction of carboxylic acids with diazodiphenylmethane
Nikolic,Uscumlic
, p. 256 - 265 (2013/04/24)
The kinetics of the reaction of benzoic, 2-methylbenzoic, phenylacetic, cyclohex-1-enecarboxylic, 2-methylcyclohex-1-enecarboxylic, and cyclohex-1-eneacetic acids with diazodiphenylmethane was studied at 30, 33, 37, 40, and 45°C in a set of 12 protic and aprotic solvents. The reactions were found to follow the second-order kinetics. The activation energy as well as the activation parameters, such as the standard entropy, the standard enthalpy, and the standard Gibbs energy of the activation, was calculated from the second-order rate constants. The solvent and structural effects on the activation energy and the standard Gibbs energy of activation, for each examined compound, were analyzed. The results of Kamlet-Taft multiple correlation analysis show that the specific solvent-solute interactions play a dominant role in the governing of the reaction. The signs of the equation coefficients support the proposed reaction mechanism.
Studies concerning the electrophilic amino-alkene cyclisation for the synthesis of bicyclic amines
Klein, Johannes E. M. N.,Mueller-Bunz, Helge,Evans, Paul
supporting information; experimental part, p. 986 - 995 (2009/05/30)
The bromination of a series of cyclohexenyl substituted secondary amines 1a-i has been investigated using Br2, PHT and NBS. In the case of Br2 and NBS the secondary amines preferentially undergo N-bromination. In contrast, PHT cleanly affords the products of alkene dibromination. In the case of Br2 the N-bromo species then give the products of alkene dibromination, albeit less efficiently. On subsequent treatment with K2CO3 these dibromides form the corresponding hexahydroindoles 2a-h and octahydroquinoline 2i. The presence of an N-substituent bearing a stereogenic centre (1h and 1i) was studied and the products 2h and 2i were isolated with no diastereoselectivity. When NBS was used a novel cyclisation, forming bromo-substituted octahydroindoles 9a,b and d, was observed. In relation to this sequence it was shown that these products were not intermediates in the former Br2/PHT processes and that the reaction only proceeded in the presence of the succinimide by-product of N-bromination.
α,β-unsaturated aldehydes as substrates for asymmetric C-C bond forming reactions with thiamin diphosphate (ThDP)-dependent enzymes
Cosp, Anabel,Dresen, Carola,Pohl, Martina,Walter, Lydia,Roehr, Caroline,Mueller, Michael
experimental part, p. 759 - 771 (2009/04/10)
The enzymes benzaldehyde lyase (BAL) from Pseudomonas fluorescens, benzoylformate decarboxylase (BFD) from Pseudomonas putida and pyruvate decarboxylase (PDC) from Saccharomyces cerevisiae provide different C-C bond forming possibilities of α,β-unsaturated aldehydes with aliphatic and aromatic aldehydes. Structure elucidation and determination of the absolute configuration of the products, which were obtained with high regio- and stereoselectivity were carried out. Selective 1,2-reactivity with yields of 75% and >98% ee, for one single isomer (A) were obtained, by choosing the suitable enzyme in combination with the appropriate substrates. By varying enzymes or substrates the regioisomeric hydroxy ketones C, with up to >99% ee, can be obtained. The application of these new chiral building blocks in the synthesis of natural products or biological active substances is considerably facilitated by applying the different ThDP-dependent enzymes as catalysts.
Medium-dependent lithiated side products in the reductive lithiation of allylic phenyl thioethers. Diethyl ether versus tetrahydrofuran
Screttas, Constantinos G.,Heropoulos, Georgios A.,Micha-Screttas, Maria,Steele, Barry R.
, p. 4357 - 4360 (2007/10/03)
Diethyl ether is a convenient solvent for the reductive lithiation of allylic phenyl thioethers without the serious complications, which occur when the reaction is carried out in tetrahydrofuran.
Reaction of N-acetylimidazole with enamines
Cook, Gilbert,Waddle, Julie L.
, p. 6923 - 6925 (2007/10/03)
N-Acetylimidazole is a commonly used acylating reagent. When it is allowed to react with several typical enamines, amides are produced rather than the expected acylated enamines.
Thallium trinitrate mediated oxidation of 3-alkenols: Ring contraction vs cyclization
Ferraz, Helena M. C.,Longo Jr., Luiz S.,Zukerman-Schpector, Julio
, p. 3518 - 3521 (2007/10/03)
The reaction of a series of six-membered ring 3-alkenols with thallium trinitrate (TTN) in three different experimental conditions was studied. Either cyclization products or ring contraction products were obtained, depending on the structure of the substrate as well as the nature of the solvent. The reaction of a seven-membered ring 3-alkenol with TTN led to the ring contraction product exclusively.
