The Racemization and Geometrical Isomerization of Oxiranes

1972 ◽  
Vol 50 (3) ◽  
pp. 428-433 ◽  
Author(s):  
Helen H. J. MacDonald ◽  
Robert J. Crawford
Keyword(s):  
Optically Active ◽  
Oxirane Ring ◽  
Geometrical Isomerization ◽  
Kinetics Of ◽  
Cis Isomer

Optically active trans-2-phenyl-3-p-tolyloxirane and cis-2-phenyl-3-p-tolyloxirane were synthesized and the kinetics of their racemization and geometrical isomerization were studied.The slower rate of racemization of the cis-isomer compared with that of the trans is attributed to the conrotatory opening of the oxirane ring.

[1H,15N] N.M.R. Kinetic Studies of Reactions of cis- and trans-[PtCl2(15NH3)(c-C6H1115NH2)] with Guanosine 5'-Monophosphate

1999 ◽  
Vol 52 (3) ◽  
pp. 173 ◽  
Author(s):  
Sarah J. Barton ◽  
Kevin J. Barnham ◽  
Abraha Habtemariam ◽  
Urban Frey ◽  
Rodney E. Sue ◽  
...  
Keyword(s):  
Trans Isomer ◽  
Active Metabolite ◽  
Kinetic Studies ◽  
Trans Influence ◽  
Trans Complex ◽  
Kinetics Of Reaction ◽  
Cis And Trans ◽  
Kinetics Of ◽  
Cis Isomer ◽  
Amine Ligand

cis-[PtCl2(15NH3)(c-C6H11NH2)] is an active metabolite of the oral platinum(IV) anticancer drug cis,trans,cis-[PtCl2(CH3CO2)2(NH2)(c-C6H11NH2)]. Since it is likely that guanine bases on DNA are targets for this drug, we have analysed the kinetics of reaction of this platinum(II) metabolite with guanosine 5′-monophosphate (5′-GMP) at 310 K, pH 7, using [1H, 15N] n.m.r. methods. Reactions of the trans isomer are reported for comparison. The reactions proceed via aquated intermediates, and, for the cis isomer, the rates of aquation and substitution of H2O by 5′-GMP are 2-5 times faster trans to the amine ligand (c-C6H11NH2) compared to trans to NH3 for both the first and second steps. For the trans complex, the first aquation step is c. 3 times faster than for the cis complex, as expected from the higher trans influence of Cl¯, whereas the rate of the second aquation step (trans to N7 of 5′-GMP) is comparable to that trans to NH3. These findings have implications for the courses of reactions with DNA.

Optically active spirophosphoranes. Part VI. Kinetics of epimerization of the chiral skeleton unit

1974 ◽  
pp. 1668 ◽  
Author(s):  
Alain Klaebe ◽  
Antonio Carrelhas Cachapuz ◽  
Jean-Fran�ois Brazier ◽  
Robert Wolf
Keyword(s):  
Optically Active ◽  
Kinetics Of

scholarly journals Degradation Oxirane Ring Kinetics of Epoxidized Palm Kernel Oil-Based Crude Oleic Acid

2018 ◽  
Vol 12 (3) ◽  
pp. 296-299 ◽  
Author(s):  
Mohd Jumain Jalil ◽  
◽  
Siti Khatijah Jamaludin ◽  
Ahmad Rafizan Mohammad Daud ◽  
◽  
...  
Keyword(s):  
Oleic Acid ◽  
Palm Kernel ◽  
Oxirane Ring ◽  
Palm Kernel Oil ◽  
Kernel Oil ◽  
Kinetics Of

Asymmetrische Katalysen, 88 [1] kinetik der rh-katalysierten hydrierung von (z)-(α)-n-acetylaminozimtsäure mit optisch aktiven schalenphosphinen als liganden / Asymmetrie catalysis, 88 [1] kinetics of the rh catalysed hydrogenation of (z)-(α)-n-acetam idocinnamic acid with optically active layer-phosphines as ligands

1994 ◽  
Vol 49 (9) ◽  
pp. 1305-1308 ◽  
Author(s):  
Henri Brunner ◽  
Josef Fürst ◽  
Ulrich Nagel ◽  
Andreas Fischer
Keyword(s):  
Catalytic Activity ◽  
Active Layer ◽  
Optically Active ◽  
Catalytic Activities ◽  
Phenyl Rings ◽  
Kinetics Of ◽  
Parent Ligand

The kinetics of the hydrogenation of (Z)-(a)-N-acetamidocinnamic acid catalysed by Rh complexes of the optically active layer-phosphines 2-7 was examined. The turnover was calculated from the consumption of hydrogen during the reaction. The catalytic activities of the layer-phosphines 2-7, which depend on the position of the borneoxy substituents on the phenyl rings, were compared with the catalytic activity of the parent ligand dppe 1

Concertedness in the Thermolysis of Some 1-Pyrazolines

1974 ◽  
Vol 52 (17) ◽  
pp. 3134-3139 ◽  
Author(s):  
Robert J. Crawford ◽  
Masatomi Ohno
Keyword(s):  
Trans Isomer ◽  
Diphenyl Ether ◽  
Rate Determining Step ◽  
Nitrogen Bonds ◽  
Cis And Trans ◽  
Kinetics Of ◽  
Cis Isomer ◽  
Nitrogen Evolution

A mixture of cis- and trans-3,5-divinyl-1-pyrazoline was synthesized and isolated at 0° by the cycloaddition of vinyldiazomethane to butadiene. The kinetics of the thermolysis in diphenyl ether at 35–65° were studied by measuring the rate of nitrogen evolution. The cis isomer gave log (k1/s−1) = (12.28 ± 0.9 ) − (22.8 ± 0.4 )/θ where θ = 2.303RT in kcal mol−1, for the trans isomer log(k2/s−1) = (13.9 ± 0.9 ) − (25.7 ± 0.4 )/θ was obtained. These data when compared with those of 1-pyrazoline and 3-vinyl-1-pyrazoline lead to the conclusion that both carbon–nitrogen bonds are being broken in the rate determining step. Thus the alkyl-1-pyrazolines are concerted whereas the azoalkanes are not.

ChemInform Abstract: OPTICALLY ACTIVE SPIROPHOSPHORANES PART 6, KINETICS OF EPIMERIZATION OF THE CHIRAL SKELETON UNIT

1975 ◽  
Vol 6 (9) ◽  
pp. no-no
Author(s):  
ALAIN KLAEBE ◽  
ANTONIO CARRELHAS CACHAPUZ ◽  
JEAN-FRANCOIS BRAZIER ◽  
ROBERT WOLF
Keyword(s):  
Optically Active ◽  
Kinetics Of
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