M

Buckingham, J.

doi:10.1007/978-1-4899-3312-6_13

Cited by 5 publications

(7 citation statements)

References 294 publications

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“…The synthesis of (S)-octyl-N-(2-methyl cyclohexane carbonyl)pyroglutamate allowed the assignment of the cis and trans isomers by the measurement of the optical rotation in ethanol of a sample that contained no transhydrogenated products. A rotation ([a] D`0 ) in the same sense as that of (1S,2R)-2-methyl cyclohexane carboxylic acid ([a] 25 D À 5.2, c 1 in EtOH) [19] was observed, which suggested that the major hydrogenated isomer was (À)-(1S,2R,2'S)-methyl-N-(2-methylbenzoyl)pyroglutamate 3 b.…”

Section: Resultsmentioning

confidence: 92%

Asymmetric Synthesis of 2-Methyl Cyclohexane Carboxylic Acids by Heterogeneous Catalysis: Mechanistic Aspects

et al. 2000

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The catalytic hydrogenation of (S)-alkyl-N-(2-methylbenzoyl)pyroglutamates was studied over supported rhodium and ruthenium catalysts at room temperature and a pressure of 5 MPa. The reaction was diastereoselective with the predominant formation of (1S,2R)-2-methylcyclohexane carboxylic acid with a diastereomeric excess (de) of up to 96%. The most stable conformation was determined by means of a combination of modelling calculations, NMR spectroscopy and X-ray structural determination. In this conformation, the carbonyl group of the pyroglutamate auxiliary shields one face of the aromatic ring. The observed selectivity may thus be explained by a preferential adsorption at the unshielded face which avoids steric repulsion by the C=O group to result in a cis hydrogenation. The addition of an amine, the nature of the support (alumina or active carbon) or of the metal (Rh or Ru) were shown to give additional stabilisation of the adsorption at the unshielded face to increase the diastereoisomeric excess.

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Section: Resultsmentioning

confidence: 92%

Asymmetric Synthesis of 2-Methyl Cyclohexane Carboxylic Acids by Heterogeneous Catalysis: Mechanistic Aspects

et al. 2000

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“…Using the linear correlation above, C p is a suitable marker for predicting the boiling temperature of large PAHs. To check the accuracy of the proposed linear equation, extra data, including large PAHs such as ovalene, were used as shown in Table . − ,− The Δ S ( T ), Δ H ( T ) and Δ G ( T ) for large PAHs could not be obtained using the G3 method, so this data is not considered in Figure a. The extra validations shown in Figure d further confirm that C p is an excellent tracer for the PAH boiling temperature.…”

Section: Results and Discussionmentioning

confidence: 99%

Gas-to-Liquid Phase Transition of PAH at Flame Temperatures

Liu

Sarathy

et al. 2020

J. Phys. Chem. A

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Significant evidence has shown that soot can be formed from polycyclic aromatic hydrocarbon (PAH) in combustion environments, but the transition of high molecular PAH from the gas phase to soot in a liquid or solid state remains unclear. In this study, the relationships between the boiling points of various planar PAHs and their thermodynamic properties are systematically investigated, to find a satisfactory marker for the phase transition event. Temperature-dependent thermodynamic properties, including entropy, specific heat capacity, enthalpy, and Gibbs free energy, are simultaneously calculated for PAHs, using density functional theory and three composite compound methods. Comparison of the results indicates that the individual G3 method, plus an atomization reaction approach, produces the most accurate thermochemistry parameters. Compared to entropy, enthalpy, and Gibbs free energy, the specific heat capacity at 298 K is found to be a better marker for the boiling point of PAHs due to the observed linear correlation, predictable characteristics, and fidelity of accuracy as a function of temperature. The correlation equation Y = 10.996X + 122.111 is proposed (where Y is the boiling temperature (K) and X is C p at 298 K (cal/K/mol)). The standard deviation is as low as 16.7 K when comparing the calculated boiling points and experimentally determined values for 25 different aromatic species ranging from benzene to ovalene (C 32 H 14 ). The effects of carbon number, structural arrangement, and partial pressure on the boiling point of large planar PAH are discussed. The results reveal that the carbon number in large planar PAH is the dominant factor determining its boiling points. It is shown that PAHs containing about 60−65 carbon atoms are likely to exist as liquids in flames, although the partial pressure of such species is very low.

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“…After stirring for 1 h, the mixture was filtered, and the filtrate was evaporated in vacuo to provide a colorless oil which was crystallized from hexane. 2-Iodobenzaldehyde 9b (9.0 g, 91%) was obtained as a brown powder: mp 37−38 °C (hexane) (lit …”

Section: Methodsmentioning

confidence: 99%

“…The residue was washed with chloroform and evaporated under reduced pressure. Crystallization from MeOH afforded bromoveratraldehyde 9c (13.1 g, 89%) as a white powder: mp 147−148 °C (MeOH) (lit . 149−151 °C (MeOH)); R f 0.54 (3% EtOAc/CH 2 Cl 2 ); 1 H NMR (CDCl 3 ) δ 3.92 (3H, s), 3.96 (3H, s), 7.06 (1H, s), 7.42 (1H, s) 10.19 (1H, s); 13 C NMR (CDCl 3 ) δ 55.9, 56.3, 110.2, 115.3, 120.2, 126.3, 148.7, 154.3 190.5; FTIR (neat film, cm -1 ): 1669; EIMS ( m / z , %) 246 (M + 1, 94), 244 (M − 1, 100), 231 (16), 229 (18).…”

Section: Methodsmentioning

confidence: 99%

A Convenient Strategy for the Synthesis of 4,5-Bis(o-haloaryl)isoxazoles

et al. 2000

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A series of new 1,2-bis(o-haloaryl)ethanones is efficiently prepared and applied to the synthesis of 4,5-bis(o-haloaryl)isoxazoles. Isolation of intermediate hydroxyisoxazolines, which are structurally examined, provides a definitive proof for a heterocyclization mechanism based on an amine exchange process. The isolation and X-ray crystallographic studies of significant side products such as benzamides and triarylpropionitriles are also described.

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M

Cited by 5 publications

References 294 publications

Asymmetric Synthesis of 2-Methyl Cyclohexane Carboxylic Acids by Heterogeneous Catalysis: Mechanistic Aspects

Asymmetric Synthesis of 2-Methyl Cyclohexane Carboxylic Acids by Heterogeneous Catalysis: Mechanistic Aspects

Gas-to-Liquid Phase Transition of PAH at Flame Temperatures

A Convenient Strategy for the Synthesis of 4,5-Bis(o-haloaryl)isoxazoles

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