62375-98-8Relevant academic research and scientific papers
Enolization rates control mono-: Versus di-fluorination of 1,3-dicarbonyl derivatives
Rozatian, Neshat,Beeby, Andrew,Ashworth, Ian W.,Sandford, Graham,Hodgson, David R.W.
, p. 10318 - 10330 (2019/11/20)
Fluorine-containing 1,3-dicarbonyl derivatives are essential building blocks for drug discovery and manufacture. To understand the factors that determine selectivity between mono- and di-fluorination of 1,3-dicarbonyl systems, we have performed kinetic studies of keto-enol tautomerism and fluorination processes. Photoketonization of 1,3-diaryl-1,3-dicarbonyl derivatives and their 2-fluoro analogues is coupled with relaxation kinetics to determine enolization rates. Reaction additives such as water accelerate enolization processes, especially of 2-fluoro-1,3-dicarbonyl systems. Kinetic studies of enol fluorination with Selectfluor and NFSI reveal the quantitative effects of 2-fluorination upon enol nucleophilicity towards reagents of markedly different electrophilicity. Our findings have important implications for the synthesis of α,α-difluoroketonic compounds, providing valuable quantitative information to aid in the design of fluorination and difluorination reactions.
New Fluorescence Domain "excited Multimer" Formed upon Photoexcitation of Continuously Stacked Diaroylmethanatoboron Difluoride Molecules with Fused π-Orbitals in Crystals
Sakai, Atsushi,Ohta, Eisuke,Yoshimoto, Yuichi,Tanaka, Mirai,Matsui, Yasunori,Mizuno, Kazuhiko,Ikeda, Hiroshi
supporting information, p. 18128 - 18137 (2015/12/24)
The crystal-packing structures of seven derivatives of diaroylmethanatoboron difluoride (1 a-gBF2) are characterized by no overlap of the π-conjugated main units of two adjacent molecules (typeI), overlap of the benzene ring π-orbitals of two adjacent molecules (typeII), and overlap of the benzene and dihydrodioxaborinine rings π-orbitals of adjacent molecules (typeIII). The crystal-packing structures govern the fluorescence (FL) properties in the crystalline states. The FL domain that is present in typeI crystals, in which intermolecular orbital interactions are absent, leads to excited monomer-like FL properties. In the case of the typeII crystals, the presence of intermolecular overlap of the benzene rings π-orbitals generates new FL domains, referred to as "excited multimers", which possess allowed S0-S1 electronic transitions and, as a result, similar FL lifetimes at longer wavelengths than the FL of the typeI crystals. Finally, intermolecular overlap of the benzene and dihydrodioxaborinine ring π-orbitals in the typeIII crystals leads to "excited multimer" domains with forbidden S0-S1 electronic transitions and longer FL lifetimes at similar wavelengths as that in typeI crystals.
Preparation of β-keto esters and β-diketones by C-acylation/deacetylation of acetoacetic esters and acetonyl ketones with 1-acylbenzotriazoles
Katritzky, Alan R.,Wang, Zuoquan,Wang, Mingyi,Wilkerson, Chavon R.,Hall, C. Dennis,Akhmedov, Novruz G.
, p. 6617 - 6622 (2007/10/03)
Acyl-, aroyl-, and heteroaroyl-acetic esters 6a-f and 8a-1 are prepared by reactions of 1-acylbenzotriazoles 1a-k with acetoacetic esters 5 or 7a,b in the presence of sodium hydride followed by regioselective deacetylation. Similar C-acylation/deacetylati
Reactions of N-unsubstituted 4-amino-1-azadienes towards electrophiles
Barluenga, José,Del Pozo, Carlos,Olano, Bernardo
, p. 133 - 140 (2007/10/03)
Several reactions releated to the ambident nucleophilicity of N-unsubstituted azadienes 1 are described. Thus, reaction of 1 with alkylating agents and iodobispyridinium tetrafluoroborate (IPy2BF4) leads to the C-substituted azadienes 3 and 5 respectively. Azadienes 1 and 3 are converted to the carbonyl derivatives 2 and 4 by mild hydrolysis. On the other hand, azadienes 1, 3 and 5 react through the nitrogen atoms with several carbonyl centered electrophiles to give nitrogen heterocycles such as pyrimidines 6 and 9 and dihydropyrimidines 11. All those processes are totally regioselective, azadienes 1 and 3 showing a lower nucleophilicity at nitrogen than N-substituted azadienes.
