نتایج جستجو برای: dialkyl acetylene dicarboxylates

تعداد نتایج: 5036  

Journal: :Bulletin of the Chemical Society of Japan 1972

Journal: :iranian journal of catalysis 2015
mehdi abaszadeh mohammad seifi majid ghashang

the synthesis of diethyl/methyl 1,3-diaryl-1,2,3,6-tetrahydro-pyrimidine-4,5-dicarboxylates can be achieved using one-pot reaction from dialkylacetylene dicarboxylate, amines, and formaldehyde by employing hydrated phosphomolybdic acid (h3[p(mo3o10)4].xh2o) as catalyst at room temperature. the effect of various solvent and catalyst amount was investigated. the salient features of the present me...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1974
R D Vernet V Boekelheide

A comparison of the (13)C nuclear magnetic resonance chemical shifts of some 15,16-dialkyl-15,16-dihydropyrenes with the corresponding 15,16-dialkyl-2,7,15,16-tetrahydropyrenes provides a measure of the effect of ring current on carbon-13 chemical shifts in which other effects may be expected to be negligibly small. The general conclusion is that the absolute magnitude of the ring-current effec...

Journal: :The Journal of biological chemistry 2000
J Christiansen L C Seefeldt D R Dean

Nitrogenase catalyzes the MgATP-dependent reduction of dinitrogen gas to ammonia. In addition to the physiological substrate, nitrogenase catalyzes reduction of a variety of other multiply bonded substrates, such as acetylene, nitrous oxide, and azide. Although carbon monoxide (CO) is not reduced by nitrogenase, it is a potent inhibitor of all nitrogenase catalyzed substrate reductions except p...

Journal: :Journal of bacteriology 1975
J M Rivera-Ortiz R H Burris

Examination of interactions among various substrates and inhibitors reacting with a partially purified nitrogenase from Azotobacter vinelandii has shown that: nitrous oxide is competitive with N2; carbon monixide and acetylene are noncompetitive with N2; carbon monoxide, cyanide, and nitrous oxide are noncompetitive with acetylene, whereas N2 is competitive with acetylene; carbon monoxide is no...

Journal: :The Biochemical journal 1985
M R Hyman P M Wood

Acetylene brings about a progressive inactivation of ammonia mono-oxygenase, the ammonia-oxidizing enzyme in Nitrosomonas europaea. High NH4+ ion concentrations were protective. The inactivation followed first-order kinetics, with a rate constant of 1.5 min-1 at saturating concentrations of acetylene. If acetylene was added in the absence of O2, the cells remained active until O2 was re-introdu...

Journal: :Plant physiology 1988
C Sloger P van Berkum

Endogenous ethylene production was evaluated as a source of ethylene during acetylene reduction assays with freshly collected roots of field-grown corn, Zea mays L. cv Funks G-4646, and sorghum, Sorghum bicolor (L.) Moench. cv CK-60A. Ethylene production was not detected when roots were incubated in air without acetylene. The presence of endogenous ethylene production was confirmed when roots w...

Journal: :The Journal of chemical physics 2013
Mohamed El-Amine Madjet Zheng Li Oriol Vendrell

Non-adiabatic dynamics of the acetylene cation is investigated using mixed quantum-classical dynamics based on trajectory surface hopping. To describe the non-adiabatic effects, two surface hopping methods are used, namely, Tully's fewest switches and Landau-Zener surface hopping. Similarities and differences between the results based on those two methods are discussed. We find that the photoio...

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