Solvolyses of para-substituted benzoyl chlorides in trifluoroethanol and in highly aqueous media

Bentley, T. William; Harris, H. C.

doi:10.1039/p29860000619

Cited by 42 publications

(76 citation statements)

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“…In aqueous TFE a value of 0.33 ± 0.03 in observed across a range of 97%–50% TFE (Table 2). These values are similar to those for p -methoxybenzoyl chloride, also considered to solvolyze by a mechanism close to S N 1 but with some nucleophilic assistance [76,77]. …”

Section: Solvolyses Of Nn-diarylcarbamoyl Chloridessupporting

confidence: 75%

Mechanistic Studies of the Solvolyses of Carbamoyl Chlorides and Related Reactions

D’Souza

Kevill

2016

IJMS

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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.

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Section: Solvolyses Of Nn-diarylcarbamoyl Chloridessupporting

confidence: 75%

Mechanistic Studies of the Solvolyses of Carbamoyl Chlorides and Related Reactions

D’Souza

Kevill

2016

IJMS

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“…Substrates of 3 and 5 were reported that they are mainly followed by unimolecular pathway (ionization) due to the resonance effect of paramethoxy substituent. [6][7][8][9]15 The l/m ratio of 1 in all range of solvents was 0.47, it is the similar value of 3 and 5, which means that the solvolysis reaction pathway of 1 containing para-methoxy substituent, is consistent with the results of 3 and 5. In case of 2, the l/m ratio was 2.59 in 17 nucleophilic solvents and was 0.64 in 8 electrophilic solvents, respectively.…”

supporting

confidence: 78%

Kinetic and Theoretical Consideration of 3,4- and 3,5-Dimethoxybenzoyl Chlorides Solvolyses

Park

Kevill²

2013

Bulletin of the Korean Chemical Society

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The solvolysis rate constants of 3,4-(1) and 3,5-dimethoxybenzoyl (2) chlorides were measured in various pure and binary solvents at 25.0 o C, and studied by application of the extended Grunwald-Winstein (G-W) equation, kinetic solvent isotope effect in methanolysis and activation parameters. The solvolysis of 1 was interpreted as the unimolecular pathway due to a predominant resonance effect from para-methoxy substituent like 4-methoxybenzoyl chloride (3), while that of 2 was evaluated as the dual mechanism, with unimolecular or bimolecular reaction pathway according to the character of solvent systems (high electrophilic/nucleophilic) chosen, caused by the inductive effect by two meta-methoxy substituents, no resonance one. In the solvolyses of 1 and 2 with two -OCH 3 groups, the resonance effect of para-methoxy substituent is more important to decide the mechanism than the inductive effect with other corresponding evidences.

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“…Kinetic methods, based on conductivity [1,10], spectrophotometric [31] and titrimetric [41] measurements, were as described previously.…”

Section: Methodsmentioning

confidence: 99%

Solvolyses of Benzoyl Chlorides in Weakly Nucleophilic Media

Bentley

Harris

2011

IJMS

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Rate constants and activations parameters are reported for solvolyses of p-Z-substituted benzoyl chlorides (1, Z = OMe, Me, H, and Cl) in 97% w/w hexafluoroisopropanol-water (97H). Additional kinetic data are reported for solvolyses in acetic and formic acids. Plots of log k vs. σp in 97H are consistent with previous research showing that a cationic reaction channel is dominant, even for solvolyses of 1, Z = NO2. A benzoyl cation intermediate was trapped by Friedel-Crafts reaction with 1,3,5-trimethoxybenzene in hexafluoroisopropanol. The results are explained by an SN2-SN1 spectrum of mechanisms with variations in nucleophilic solvent assistance. Ab initio calculations of heterolytic bond dissociation energies of various chloro- and fluoro-substituted and other benzoyl chlorides are correlated with log k for solvolyses.

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Solvolyses of para-substituted benzoyl chlorides in trifluoroethanol and in highly aqueous media

Cited by 42 publications

References 0 publications

Mechanistic Studies of the Solvolyses of Carbamoyl Chlorides and Related Reactions

Mechanistic Studies of the Solvolyses of Carbamoyl Chlorides and Related Reactions

Kinetic and Theoretical Consideration of 3,4- and 3,5-Dimethoxybenzoyl Chlorides Solvolyses

Solvolyses of Benzoyl Chlorides in Weakly Nucleophilic Media

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