prikaz prve stranice dokumenta Mechanism of 1,2-hydride shift in some carbocations involved in steroid biosynthesis
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Mechanism of 1,2-hydride shift in some carbocations involved in steroid biosynthesis
Croatica Chemica Acta, 74 (2001), 4; 801-813. urn:nbn:hr:163:127588
Vrček, Valerije; Vinković Vrček, Ivana; Kronja, Olga

Institucijski repozitorij: Repozitorij Farmaceutsko-biokemijskog fakulteta Sveučilišta u Zagrebu

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Vrček, V., Vinković Vrček, I. i Kronja, O. (2001). Mechanism of 1,2-hydride shift in some carbocations involved in steroid biosynthesis. Croatica Chemica Acta, 74. (4), 801-813. Preuzeto s https://urn.nsk.hr/urn:nbn:hr:163:127588

Vrček, Valerije, et al. "Mechanism of 1,2-hydride shift in some carbocations involved in steroid biosynthesis." Croatica Chemica Acta, vol. 74, br. 4, 2001, str. 801-813. https://urn.nsk.hr/urn:nbn:hr:163:127588

Vrček, Valerije, Ivana Vinković Vrček i Olga Kronja. "Mechanism of 1,2-hydride shift in some carbocations involved in steroid biosynthesis." Croatica Chemica Acta 74, br. 4 (2001): 801-813. https://urn.nsk.hr/urn:nbn:hr:163:127588

Vrček, V., Vinković Vrček, I. i Kronja, O. (2001) 'Mechanism of 1,2-hydride shift in some carbocations involved in steroid biosynthesis', Croatica Chemica Acta, 74(4), str. 801-813. Preuzeto s: https://urn.nsk.hr/urn:nbn:hr:163:127588 (Datum pristupa: 23.12.2024.)

Vrček V, Vinković Vrček I, Kronja O. Mechanism of 1,2-hydride shift in some carbocations involved in steroid biosynthesis. Croatica Chemica Acta [Internet]. 2001. [pristupljeno 23.12.2024.];74(4):801-813. Dostupno na: https://urn.nsk.hr/urn:nbn:hr:163:127588

V. Vrček, I. Vinković Vrček i O. Kronja, "Mechanism of 1,2-hydride shift in some carbocations involved in steroid biosynthesis", Croatica Chemica Acta, vol. 74, br. 4, str. 801-813, 2001. [Online]. Dostupno na: https://urn.nsk.hr/urn:nbn:hr:163:127588. [Citirano: 23.12.2024.]

Za citiranje koristite ovu mrežnu adresu: https://urn.nsk.hr/urn:nbn:hr:163:127588
Podaci o radu
Naslov (engleski)Mechanism of 1,2-hydride shift in some carbocations involved in steroid biosynthesis
AutorValerije Vrček
AutorIvana Vinković Vrček
AutorOlga Kronja
Autorova ustanovaSveučilište u Zagrebu
Farmaceutsko-biokemijski fakultet
(Zavod za organsku kemiju)
Znanstveno / umjetničko
područje, polje i grana		PRIRODNE ZNANOSTI
Kemija
Organska kemija
Sažetak (engleski)
The mechanism of 1,2-hydride shift in protosteryl C(20) cation (<b>1A</b>) and in dammarenyl C(20) cation (<b>2A</b>) was investigated by the semi-empirical AM1 method and <i>ab initio</i> quantum Chemical calculations (HF/3-21G level). Stationary points <b>1A/1B</b> and <b>2A/2B</b>, and the corresponding transition hydrido-bridged structures <b>1TS</b> and <b>2TS</b> were located on the energy surface. Process <b>1A→1B</b> turned out to be energetically more favorable than process <b>2A→2B</b> by <i>ca</i>. 9 kcal mol<sup>-1</sup>, mostly due to the unfavorable steric repulsive interaction between the methyl group at C(14) and the <i>β</i>-oriented side chain at C(17) in <b>1A</b> and the lack of CC-hyperconjugative stabilization in <b>1A</b>. The exothermicity of processes <b>1A→1B</b> and <b>2A→2B</b> was increased by subsequent introduction of substituents (H, Me, i-Pr, and <i>t</i>-Bu) at C(14). The more pronounced trend in <b>1A→1B</b> proves that the origin of the relative stability of <b>1B</b> comes from the steric interactions in <b>1A</b>. Introduction of the halogen atom (F, Cl, and Br), due to its -I effect and relatively small size, changed the direction of the equilibrium <b>1A<sub>Y</sub>/1B<sub>Y</sub></b>, and <b>1A<sub>Y</sub></b> was found to be by <i>ca</i>. 3 kcal mol<sup>-1</sup> more stable than <b>1B<sub>Y</sub></b>.
Ključne riječi (engleski)
Jezikengleski
Vrsta publikacijeZnanstveni rad - Izvorni znanstveni rad
Status objaveObjavljen
Vrsta recenzijeRecenziran - međunarodna recenzija
Verzija publikacijeObjavljena verzija rada (izdavačev PDF)
Naslov časopisaCroatica Chemica Acta
Brojčani podacivol. 74, br. 4, str. 801-813
p-ISSN0011-1643
e-ISSN1334-417X
URN:NBNurn:nbn:hr:163:127588
Datum objave publikacije2001
URL dokumentahttps://hrcak.srce.hr/131956
Vrsta resursaTekst
Prava pristupaOtvoreni pristup
Uvjeti korištenjaIkona licence Zaštićeno autorskim pravom.
Datum i vrijeme pohrane2020-04-29 11:06:46