نتایج جستجو برای: dialkyl acetylenedicarboxylate

تعداد نتایج: 1366  

2009
DeEtta Hein Rudy J. Richardson Paul F. Hollenberg Peter Mancuso Jeanne Stuckey Daphne Louise Rudy Richardson Tim Kropp Angelo Napolitano Martin Philbert Rita Loch

Serine esterases are inhibited by dialkyl fluorinated aminophosphonate (FAP) compounds of general formula, (RO)2P(O)C(CF3)2NHS(O)2C6H5, where R = alkyl. It has been hypothesized that the active site serine of the esterase covalently attaches to the phosphoryl moiety of the FAP compound, resulting in formation of a dialkyl phosphate adduct that can age by net loss of an R-group. However, this me...

2012
S. M. HABIBI

The Kinetic studies were made of the reactions between triphenylphosphine, dialkyl acetylenedicarboxylates in the presence of NH-acid, such as harman. To determine the kinetic parameters of the reactions, they were monitored by UV spectrophotometery. The second order fits were automatically drawn and the values of the second order rate constant (k2) were calculated using standard equations with...

Journal: :Applied and environmental microbiology 2010
Hirofumi Hara Gordon R Stewart William W Mohn

Phthalate esters (PEs) are important environmental pollutants. While the biodegradation of the parent compound, phthalate (PTH), is well characterized, the biodegradation of PEs is not well understood. In particular, prior to this study, genes involved in the uptake and hydrolysis of these compounds were not conclusively identified. We found that Rhodococcus jostii RHA1 could grow on a variety ...

2015
Jandré de Villiers Marianne de Villiers Edzard M Geertsema Hans Raj Gerrit J Poelarends

A simple, three-step chemoenzymatic synthesis of l-threo-3-benzyloxyaspartate (l-TBOA), as well as l-TBOA derivatives with F, CF3, and CH3 substituents at the aromatic ring, starting from dimethyl acetylenedicarboxylate was investigated. These chiral amino acids, which are extremely difficult to prepare by chemical synthesis, form an important class of inhibitors of excitatory amino acid transp...

Journal: :Journal of the American Chemical Society 2004
Phil S Baran Alexandros L Zografos Daniel P O'Malley

Gifted with novel chemical features and extraordinary biological activity, sceptrin has remained a prominent unanswered synthetic challenge since its characterization in 1981 by Faulkner and Clardy. A concise and practical solution to the myriad of chemical challenges posed by sceptrin is reported in this Communication. Thus, through a sequence involving rearrangement of an oxaquadricyclane, a ...

2013
Mohammad Piltan Loghman Moradi Golaleh Abasi Seyed Amir Zarei

The catalyst-free multicomponent reaction of 1,2-diaminobenzene, dialkyl acetylenedicarboxylates, and ethyl bromopyruvate forms pyrrolo[1,2-a]quinoxaline derivatives in good yields. Ethylenediamine also reacts under similar conditions to produce new pyrrolo[1,2-a]pyrazine derivatives.

Journal: :Chemical communications 2012
Depeng Zhao Lijuan Mao Linqing Wang Dongxu Yang Rui Wang

The catalytic asymmetric phospha-Michael reaction of dialkyl phosphine oxides with β,β-disubstituted α,β-unsaturated carbonyl compounds was achieved. The products bearing tetrasubstituted carbon stereocenters were obtained in high yields with excellent enantioselectivities (up to >99% ee).

Journal: :Chemical communications 2003
Thomas M Cameron John C Gordon Ryszard Michalczyk Brian L Scott

We report herein the synthesis and characterization of a lutetium dialkyl complex supported by a multidentate, anilido-pyridine-imine ligand and its subsequent transformation into an unprecedented cationic monoalkyl derivative.

Journal: :Organic & biomolecular chemistry 2011
Riccardo Mossetti Diego Caprioglio Giampiero Colombano Gian Cesare Tron Tracey Pirali

α-Isocyanoacetamides, acyl chlorides and dialkylacetylenedicarboxylates undergo a smooth multicomponent reaction to produce dialkyl 2-acyl-5-aminofuran-3,4-dicarboxylates in good yield. The scope and mechanism of this new multicomponent transformation are discussed.

Journal: :Chemical communications 2005
Weijun Niu Brett Rambo Mark D Smith John J Lavigne

Solid-state and solution analysis shows that dialkyl substituents on the central phenyl ring of bis(dioxaborole)s, such as , do not have an appreciable effect on the planarity but do significantly alter the supramolecular assembly of these compounds.

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