SVIBOR - Papers quoted in CC - project code: 1-07-006
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SVIBOR - Collecting Data on Projects in Croatia
Papers quoted in Current Contents on project 1-07-006
Quoted papers: 5
Other papers: 9
Total: 14
Title: Lack of Secondary beta-Deuterium Kinetic Isotope Effects
in the Solvolysis of 2-Chloro-3-hydrosqualene. A Case of Extended
pi-Participation and Indication of Concerted Biomimetic Polycyclization
- Authors:
- Kronja, Olga (23865)
- Orlović, Mirko (38572)
- Humski, Krešimir
- Borčić, Stanko
Journal: Journal of the American Chemical Society
Number: 6
ISSN: 0002-7863
Volume: 113
Year: 1991
Pages: from 2306 to 2308
Number of references: 17
Language: engleski
Summary: 2-Chloro-2-hydrosqualene, its saturated and deuterated
analogueswere prepared starting from squalene. These substrates
weresubjected to solvolysis and the reaction rates were measured in80%
aqueous ethanol. Even though rate effects and activationparameters do not
reveal any participation, secondary deuteriumkinetic isotope effect
indicates that at least two double CCbonds are involved in the rate
determining step, i.e. extendedpi-participation occurs under these
conditions.
Keywords: secondary deuterium kinetic isotope effect, extended pi-participation, concerted reaction
Title: Solvolysis Kinetics of
1-Chloro-1-phenyl-5,9,14,18,22-pentamthyl-5,9,13,17,21-tricosapentaene, a
Squalene Derivative. Indication of Participation
- Authors:
- Malnar, Ivica
- Kronja, Olga (23865)
- Humski, Krešimir
- Borčić, Stanko
Journal: Croatica Chemica Acta
Number: 3
ISSN: 0011-1643
Volume: 65
Year: 1992
Pages: from 547 to 549
Number of references: 5
Language: engleski
Summary: The title compound was prepared starting from squalene and
thesolvolysis rate and activation parameters were calculated.According to
the values obtained it is concluded that thecompound solvolyzes probably
with participation of at least onedouble bond.
Keywords: squalene derivative, solvolysis, participation
Title: Deuterium and Carbon-13 Scrambling Processes in Isopropyl
Cation
- Authors:
- Saunders, Martin
- Hewett, Alan P.
- Kronja, Olga (23865)
Journal: Croatica Chemica Acta
Number: 3
ISSN: 0011-1643
Volume: 65
Year: 1992
Pages: from 673 to 679
Number of references: 13
Language: engleski
Summary: The degenerate rearrangement processes in isopropyl cation
werestudied using isotopically double labeled 2-propyl-2-13C-2-d1cation.
The first step of the rearrangement is a shift of onemethyl hydrogen to
form n-propyl cation, followed by rotation ofthe methylene group. Rotation
in one direction (Process I) leadsto formation of isopropyl cation with
interchange ofhydrogen, while in other direction (Process II) results
aformation of intermediate protonated cyclopropane. Relative ratesof
Processes I and II were determined to be 3.4 on the basis ofthe composition
of the mixture using Runge-Kutta integration tosimulate the kinetics.
Keywords: isopropyl cation, degenerative rearrangement, protonated cyclopropane
Title: A Kinetic Approach to the Mechanism of Cationic
Polyolefinic Cyclization. Simple and Extended pi-Participation
- Authors:
- Borčić, Stanko
- Kronja, Olga (23865)
- Humski, Krešimir
Journal: Croatica Chemica Acta
Number: 2
ISSN: 0011-1643
Volume: 67
Year: 1994
Pages: from 171 to 188
Number of references: 38
Language: engleski
Summary: This review deals with mechanism of the biomimetic olefinic
cationic polycyclizations considering relative rate effects, activation
parameters, substituent rate effects, sigma, ro correlations and secondary
deuterium kinetic isotope effects (KIE) in solvolysis, obtained with
tertiary and benzylic substrates comprising one, two or more double bonds,
respectively, sited at the same positions as in the natural precursors
(C-5, C-9, C-13).
Keywords: biomimetic polycyclization, deuterium kinetic isotope effect, pi-participation
Title: 13C and 1H NMR Line Broadening in Desferrioxamine B
Spectra. Kinetics and Mechanism of Siderophore Chemistry
- Authors:
- Biruš, Mladen
- Gabričević, Mario
- Kronja, Olga (23865)
- Klaić, Branimir
Journal: Inorganic Chemistry
ISSN: 1334-3110
Volume: 34
Year: 1995
Pages: from 3110 to 3113
Number of references: 25
Language: engleski
Summary: A slow rotation around C-N bonds of naturallz occuring
trishydroxamato acid, desferrioxamine B, was investigated by 1H, 13C
dynamic NMR techniques. Correspopnding rate constants for the C-terminal,
middle and N-terminal hydroxamates are 12 s-1, 15 s-1, 9 s-1, respectively.
The E form of hydroxamate ligands dominates over the Y form in an
approximate ratio 4:1. The slow rotation arround the C-N bond of the middle
hydroxamato group is proposed to be the rate determining step in
dechelation of the middle hydroxamato group. The rate of the E-Z
isomerization of the C-terminal group is found to be the rate determinig
step in the complexation of La(III) and Cu(II) with desferioxamine B.
Keywords: siderophore chemistry, NMR line broadening, desferrioxamine B
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