LIVIVO - Suchergebnisse -

Suchergebnis

Treffer 1 - 10 von insgesamt 35

Suchoptionen

Artikel: Mechanistic studies of the solvolysis of alkanesulfonyl and arenesulfonyl halides.

D'Souza, Malcolm J / Kevill, Dennis N

2022 Band 18, Seite(n) 120–132

Abstract: There have been several studies on the solvolysis mechanisms for alkanesulfonyl chlorides ( ... ...

Abstract	There have been several studies on the solvolysis mechanisms for alkanesulfonyl chlorides (RSO
Sprache	Englisch
Erscheinungsdatum	2022-01-17
Erscheinungsland	Germany
Dokumenttyp	Journal Article ; Review
ZDB-ID	2192461-2
ISSN	1860-5397
ISSN	1860-5397
DOI	10.3762/bjoc.18.13
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

Zusatzmaterialien

Über subito bestellen

Dieser Service ist kostenpflichtig (siehe Lieferbedingungen von subito). Bestellungen, die einen Artikel nebst Supplementary Material umfassen, werden grundsätzlich wie mehrfache Bestellungen bearbeitet. Gebühren fallen in diesen Fällen für jede einzelne Bestellung an.

Details ▾
- Kostenpflichtig bestellen

Artikel ; Online: Rate and Product Studies with 1-Adamantyl Chlorothioformate under Solvolytic Conditions.

Park, Kyoung Ho / Seong, Mi Hye / Kyong, Jin Burm / Kevill, Dennis N

International journal of molecular sciences

2021 Band 22, Heft 14

Abstract: A study was carried out on the solvolysis of 1-adamantyl chlorothioformate (1-AdSCOCl, ...

Abstract	A study was carried out on the solvolysis of 1-adamantyl chlorothioformate (1-AdSCOCl,
Mesh-Begriff(e)	Adamantane/chemistry ; Chlorine/chemistry ; Ions/chemistry ; Kinetics ; Solvents/chemistry ; Thermodynamics
Chemische Substanzen	Ions ; Solvents ; Chlorine (4R7X1O2820) ; Adamantane (PJY633525U)
Sprache	Englisch
Erscheinungsdatum	2021-07-09
Erscheinungsland	Switzerland
Dokumenttyp	Journal Article
ZDB-ID	2019364-6
ISSN	1422-0067 ; 1422-0067 ; 1661-6596
ISSN (online)	1422-0067
ISSN	1422-0067 ; 1661-6596
DOI	10.3390/ijms22147394
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

Zusatzmaterialien

Über subito bestellen

Details ▾
- Kostenpflichtig bestellen

Artikel ; Online: The Effect of the

Park, Kyoung-Ho / Rhu, Chan Joo / Kyong, Jin Burm / Kevill, Dennis N

International journal of molecular sciences

2019 Band 20, Heft 16

Abstract: A kinetic study was carried out on the solvolysis ... ...

Abstract	A kinetic study was carried out on the solvolysis of
Mesh-Begriff(e)	Hydrolysis ; Nitrobenzenes/chemistry
Chemische Substanzen	Nitrobenzenes ; 4-nitrobenzyl bromide (100-11-8)
Sprache	Englisch
Erscheinungsdatum	2019-08-18
Erscheinungsland	Switzerland
Dokumenttyp	Journal Article
ZDB-ID	2019364-6
ISSN	1422-0067 ; 1422-0067 ; 1661-6596
ISSN (online)	1422-0067
ISSN	1422-0067 ; 1661-6596
DOI	10.3390/ijms20164026
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

Zusatzmaterialien

Über subito bestellen

Details ▾
- Kostenpflichtig bestellen

Artikel ; Online: The Influence of a Terminal Chlorine Substituent on the Kinetics and the Mechanism of the Solvolyses of

D'Souza, Malcolm J / Wirick, Jeremy / Mahmoud, Osama / Kevill, Dennis N / Kyong, Jin Burm

International journal of molecular sciences

2020 Band 21, Heft 12

Abstract: A previous study of the effect of a 2-chloro substituent on the rates and the mechanisms of the solvolysis of ethyl chloroformate is extended to the effect of a 3-chloro substituent on the previously studied solvolysis of propyl chloroformate and to the ... ...

Abstract	A previous study of the effect of a 2-chloro substituent on the rates and the mechanisms of the solvolysis of ethyl chloroformate is extended to the effect of a 3-chloro substituent on the previously studied solvolysis of propyl chloroformate and to the effect of a 4-chloro substituent on the here reported rates of solvolysis of butyl chloroformate. In each comparison, the influence of the chloro substituent is shown to be nicely consistent with the proposal, largely based on the application of the extended Grunwald-Winstein equation, of an addition-elimination mechanism for solvolysis in the solvents of only modest solvent ionizing power, which changes over to an ionization mechanism for solvents of relatively high ionizing power and low nucleophilicity, such as aqueous fluoroalcohols with an appreciable fluoroalcohol content.
Mesh-Begriff(e)	Chlorine/chemistry ; Formates/chemistry ; Hydroxyl Radical/chemistry ; Kinetics ; Molecular Structure ; Solvents/chemistry
Chemische Substanzen	Formates ; Solvents ; Hydroxyl Radical (3352-57-6) ; chlorocarbonic acid (463-73-0) ; Chlorine (4R7X1O2820)
Sprache	Englisch
Erscheinungsdatum	2020-06-19
Erscheinungsland	Switzerland
Dokumenttyp	Journal Article
ZDB-ID	2019364-6
ISSN	1422-0067 ; 1422-0067 ; 1661-6596
ISSN (online)	1422-0067
ISSN	1422-0067 ; 1661-6596
DOI	10.3390/ijms21124387
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

Zusatzmaterialien

Über subito bestellen

Details ▾
- Kostenpflichtig bestellen

Artikel ; Online: Mechanistic Studies of the Solvolyses of Carbamoyl Chlorides and Related Reactions.

D'Souza, Malcolm J / Kevill, Dennis N

International journal of molecular sciences

2016 Band 17, Heft 1

Abstract: Carbamoyl chlorides are important intermediates, both in the research laboratory and in industrial scale syntheses. The most studied and used are the disubstituted derivatives, incorporating either aryl or alkyl groups (Ar2NCOCl or R2NCOCl). Sometimes, ... ...

Abstract	Carbamoyl chlorides are important intermediates, both in the research laboratory and in industrial scale syntheses. The most studied and used are the disubstituted derivatives, incorporating either aryl or alkyl groups (Ar2NCOCl or R2NCOCl). Sometimes, the groups are tied back to give a ring and piperidino- and morpholino-derivatives are commonly encountered. Some studies have been made with two different groups attached. Solvolyses tend to occur at the carbonyl carbon, with replacement of the chloride ion. Studies of both rate and products are reviewed and the solvolysis reactions are usually SN1, although addition of an amine leads to a superimposable bimolecular component. Many of the studies under solvolytic conditions include the application of the extended Grunwald-Winstein equation. The monosubstituted derivatives (ArNHCOCl or RNHCOCl) are less studied. They are readily prepared by the addition of HCl to an isocyanate. In acetonitrile, they decompose to set up and reach equilibrium with the isocyanate (ArNCO or RNCO) and HCl. Considering that the structurally related formyl chloride (HOCOCl) is highly unstable (with formation of HCl + CO2), the unsubstituted carbamoyl chloride (H2NCOCl) is remarkably stable. Recommended synthetic procedures require it to survive reaction temperatures in the 300-400 °C range. There has been very little study of its reactions.
Mesh-Begriff(e)	Carboxylic Acids/chemistry ; Chemistry Techniques, Synthetic/methods ; Chlorides/chemistry ; Solvents/chemistry
Chemische Substanzen	Carboxylic Acids ; Chlorides ; Solvents
Sprache	Englisch
Erscheinungsdatum	2016-01-15
Erscheinungsland	Switzerland
Dokumenttyp	Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S. ; Review
ZDB-ID	2019364-6
ISSN	1422-0067 ; 1422-0067 ; 1661-6596
ISSN (online)	1422-0067
ISSN	1422-0067 ; 1661-6596
DOI	10.3390/ijms17010111
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

Zusatzmaterialien

Über subito bestellen

Details ▾
- Kostenpflichtig bestellen

Artikel: Classical tosylate/chloride leaving group approach supports a tetrahedral transition state for additions to trigonal carbon.

D'Souza, Malcolm J / Wirick, Jeremy / Deol, Jasbir / Kevill, Dennis N

Trends in organic chemistry

2016 Band 19, Seite(n) 1–11

Abstract: The experimentally measured rates of solvolysis of 2-chloroethoxycarbonyl chloride (2-chloroethyl chloroformate, ...

Abstract	The experimentally measured rates of solvolysis of 2-chloroethoxycarbonyl chloride (2-chloroethyl chloroformate,
Sprache	Englisch
Erscheinungsdatum	2016-05-27
Erscheinungsland	India
Dokumenttyp	Journal Article
ISSN	0972-4362
ISSN	0972-4362
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

Zusatzmaterialien

Über subito bestellen

Fernleihe an ZB MED

Sie können sich den gewünschten Titel als lokale Nutzerin oder lokaler Nutzer von ZB MED direkt an den Standort Köln schicken lassen.

Details ▾
- Kostenpflichtig bestellen

Artikel ; Online: Influence of sulfur for oxygen substitution in the solvolytic reactions of chloroformate esters and related compounds.

D'Souza, Malcolm J / Kevill, Dennis N

International journal of molecular sciences

2014 Band 15, Heft 10, Seite(n) 18310–18332

Abstract: The replacement of oxygen within a chloroformate ester (ROCOCl) by sulfur can lead to a chlorothioformate (RSCOCl), a chlorothionoformate (ROCSCl), or a chlorodithioformate (RSCSCl). Phenyl chloroformate (PhOCOCl) reacts over the full range of solvents ... ...

Abstract	The replacement of oxygen within a chloroformate ester (ROCOCl) by sulfur can lead to a chlorothioformate (RSCOCl), a chlorothionoformate (ROCSCl), or a chlorodithioformate (RSCSCl). Phenyl chloroformate (PhOCOCl) reacts over the full range of solvents usually included in Grunwald-Winstein equation studies of solvolysis by an addition-elimination (A-E) pathway. At the other extreme, phenyl chlorodithioformate (PhSCSCl) reacts across the range by an ionization pathway. The phenyl chlorothioformate (PhSCOCl) and phenyl chlorothionoformate (PhOCSCl) react at remarkably similar rates in a given solvent and there is a dichotomy of behavior with the A-E pathway favored in solvents such as ethanol-water and the ionization mechanism favored in aqueous solvents rich in fluoroalcohol. Alkyl esters behave similarly but with increased tendency to ionization as the alkyl group goes from 1° to 2° to 3°. N,N-Disubstituted carbamoyl halides favor the ionization pathway as do also the considerably faster reacting thiocarbamoyl chlorides. The tendency towards ionization increases as, within the three contributing structures of the resonance hybrid for the formed cation, the atoms carrying positive charge (other than the central carbon) change from oxygen to sulfur to nitrogen, consistent with the relative stabilities of species with positive charge on these atoms.
Mesh-Begriff(e)	Formic Acid Esters/chemistry ; Halogenation ; Oxygen/chemistry ; Solvents/chemistry ; Sulfhydryl Compounds/chemistry ; Sulfur/chemistry
Chemische Substanzen	Formic Acid Esters ; Solvents ; Sulfhydryl Compounds ; Sulfur (70FD1KFU70) ; Oxygen (S88TT14065)
Sprache	Englisch
Erscheinungsdatum	2014-10-10
Erscheinungsland	Switzerland
Dokumenttyp	Journal Article ; Research Support, N.I.H., Extramural ; Research Support, U.S. Gov't, Non-P.H.S.
ZDB-ID	2019364-6
ISSN	1422-0067 ; 1422-0067 ; 1661-6596
ISSN (online)	1422-0067
ISSN	1422-0067 ; 1661-6596
DOI	10.3390/ijms151018310
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

Zusatzmaterialien

Über subito bestellen

Details ▾
- Kostenpflichtig bestellen

Artikel: Application of the Grunwald-Winstein Equations to Studies of Solvolytic Reactions of Chloroformate and Fluoroformate Esters.

D'Souza, Malcolm J / Kevill, Dennis N

Recent research developments in organic chemistry

2014 Band 13, Seite(n) 1–38

Abstract: Chloroformates are important laboratory and industrial chemicals with almost one hundred listed in the catalogs of leading suppliers. They are, for example, of prime importance as protecting groups in peptide synthesis. In some instances, the more stable ...

Abstract	Chloroformates are important laboratory and industrial chemicals with almost one hundred listed in the catalogs of leading suppliers. They are, for example, of prime importance as protecting groups in peptide synthesis. In some instances, the more stable fluoroformate is preferred. In recent years, the specific rates of solvolysis (
Sprache	Englisch
Erscheinungsdatum	2014-10-31
Erscheinungsland	India
Dokumenttyp	Journal Article
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

Zusatzmaterialien

Fernleihe an ZB MED

Sie können sich den gewünschten Titel als lokale Nutzerin oder lokaler Nutzer von ZB MED direkt an den Standort Köln schicken lassen.

Details ▾

Artikel: Statistical Methods for the Investigation of Solvolysis Mechanisms Illustrated by the Chlorides of the Carbomethoxy Protecting Groups NVOC and FMOC.

D'Souza, Malcolm J / Deol, Jasbir K / Pavey, Maryeah T / Kevill, Dennis N

Journal of analytical methods in chemistry

2015 Band 2015, Seite(n) 941638

Abstract: The solvolysis of 4,5-dimethoxy-2-nitrobenzyl chloroformate (NVOC-Cl, 1) is followed at 25.0°C in twenty hydroxylic solvents. A comparison with previously published rates for benzyl chloroformate and p-nitrobenzyl chloroformate indicates that the ... ...

Abstract	The solvolysis of 4,5-dimethoxy-2-nitrobenzyl chloroformate (NVOC-Cl, 1) is followed at 25.0°C in twenty hydroxylic solvents. A comparison with previously published rates for benzyl chloroformate and p-nitrobenzyl chloroformate indicates that the inductive effect of the nitro and the two methoxy groups strongly influences the rate of reaction. For 1, the specific rates of solvolysis are correlated using an extended Grunwald-Winstein (G-W) treatment. A direct comparison with the data for phenyl chloroformate (PhOCOCl) in identical solvents strongly suggests that the addition step within an addition-elimination mechanism is rate-determining for both substrates. A reevaluation of the kinetic data for 9-fluorenylmethyl chloroformate (FMOC-Cl, 2) involves a correlation of log⁡(k/k o )2 versus log⁡(k/k o )PhOCOCl. In this plot, deviations were observed in solvents rich in a hydrogen-bonding fluoroalcohol component. Omitting the aqueous fluoroalcohol rate measurements for 2 in an analysis using the extended G-W equation suggested the occurrence of dual pathways differing in the dependences upon the ionizing power and nucleophilicity of the solvent. In addition, the fluorenyl ring is rotated out of the plane containing the ether oxygen and, as a result, PhOCOCl is found to solvolyze 20 times faster than 2 in ethanol and methanol.
Sprache	Englisch
Erscheinungsdatum	2015-02-12
Erscheinungsland	Egypt
Dokumenttyp	Journal Article
ZDB-ID	2654178-6
ISSN	2090-8873 ; 2090-8865
ISSN (online)	2090-8873
ISSN	2090-8865
DOI	10.1155/2015/941638
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

Zusatzmaterialien

Über subito bestellen

Details ▾
- Kostenpflichtig bestellen

Artikel: Use of the Simple and Extended Grunwald-Winstein Equations in the Correlation of the Rates of Solvolysis of Highly Hindered Tertiary Alkyl Derivatives.

Kevill, Dennis N / D'Souza, Malcolm J

Current organic chemistry

2010 Band 14, Heft 10, Seite(n) 1037–1049

Abstract: The original Grunwald-Winstein equation (1948) involved the development of a scale of solvent ionizing power (Y). Subsequent work has refined this scale and involved the development of scales of solvent nucleophilicity (N) and a term to correct for ... ...

Abstract	The original Grunwald-Winstein equation (1948) involved the development of a scale of solvent ionizing power (Y). Subsequent work has refined this scale and involved the development of scales of solvent nucleophilicity (N) and a term to correct for deviations when aromatic rings are present, governed by the aromatic ring parameter (I). These three scales, and the sensitivities towards each, can be related to specific rates of solvolysis through linear free energy relationships (LFERs).One important area of application of LFERs has been to the solvolyses of tert-alkyl halides. It has been proposed that the solvolysis of tert-butyl chloride involves a nucleophilic component, although other workers have suggested that the effects observed are related to electrophilic not nucleophilic influences. Takeuchi (1997) studied a compound with two of the methyl groups of tert-butyl chloride replaced by neopentyl groups. For this highly-hindered substrate there was no evidence for nucleophilic participation. Liu (1998) and Takeuchi (2001) have reported concerning the solvolyses of additional significantly-hindered tertiary alkyl chlorides. Liu (2009) has presented a parallel study of bromides. Martins (2008) has considered hindered tertiary alkyl halides, mainly with carbon-carbon multiple bonds as substituents. It was proposed that the hI term was of importance, with the sensitivities (h) sometimes positive and sometimes negative. To explain negative values, it was suggested that the I scale might contain a nucleophilicity component. In this review, we bring together, with analysis and commentary, the work of Takeuchi, Liu, Martins and others concerning the solvolyses of tertiary alkyl halides, with emphasis on the relevance of the three scales that have been developed for use in Grunwald-Winstein correlations.
Sprache	Englisch
Erscheinungsdatum	2010-10-21
Erscheinungsland	Netherlands
Dokumenttyp	Journal Article
ISSN	1385-2728
ISSN	1385-2728
DOI	10.2174/138527210791130505
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

Zusatzmaterialien

Über subito bestellen

Fernleihe an ZB MED

Sie können sich den gewünschten Titel als lokale Nutzerin oder lokaler Nutzer von ZB MED direkt an den Standort Köln schicken lassen.

Details ▾
- Kostenpflichtig bestellen

Zum Seitenanfang

Ihre letzten Suchen

Zusatzmaterialien

Kategorien

Über subito bestellen

Zusatzmaterialien

Kategorien

Über subito bestellen

Zusatzmaterialien

Kategorien

Über subito bestellen

Zusatzmaterialien

Kategorien

Über subito bestellen

Zusatzmaterialien

Kategorien

Über subito bestellen

Zusatzmaterialien

Kategorien

Über subito bestellen

Fernleihe an ZB MED

Zusatzmaterialien

Kategorien

Über subito bestellen

Zusatzmaterialien

Kategorien

Fernleihe an ZB MED

Zusatzmaterialien

Kategorien

Über subito bestellen

Zusatzmaterialien

Kategorien

Über subito bestellen

Fernleihe an ZB MED