The Mechanism of Epoxide Reactions. IV.<sup>1</sup> The Reactions of Benzylamine with a Series of m- and p-Substituted Styrene Oxides in Ethanol<sup>2</sup>

Laird, R. M.; Parker, R. E.

doi:10.1021/ja01481a042

Cited by 27 publications

(18 citation statements)

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“…This trend, which seems to be common for the reaction of SO with nucleophiles similar to NBP in protic solvents, 6 Influence of the Acidity of the Medium on the Kinetic Parameters Involved in the Alkylation Process. A series of experiments was performed in media of different acidities in the 5.0 < pH < 8.0 range, because experimental limitations did not allow the reaction rate constants from eqs 7 and 8 to be determined outside this range.…”

Section: ■ Introductionmentioning

confidence: 57%

“…This result is in agreement with their distinctive fragmentation patterns, obtained by analysis of the alkylation mixtures by mass spectrometry in an excess of NBP (m/z = 335, 317, 304 for α-adduct, and m/z = 335, 121 for β-adduct), as well as with previous results obtained with other nucleophiles. 6,13,19,20,25 Assignment of the UFLC-DAD peaks was performed by comparison of their retention times, UV−vis spectra, and kinetic profiles with those of the β-adduct formed between NBP and p-nitrostyrene oxide, a substituted styrene oxide whose alkylating potential has been studied by us previously. 26 The adducts identified were α-NBP−SO (AD unα ), t R = 11.0 min, and β-NBP−SO (AD unβ ), t R = 8.5 min (see Scheme 1).…”

Section: ■ Introductionmentioning

confidence: 99%

“…6 This, together with the preference of SO for the N7-position of guanine over other nucleophile positions of the DNA bases, 7,8,13,18,27 suggests that NBP is a suitable model to investigate the reactivity of SO with DNA. 21 The good fitting of the experimental A AD /t data obtained under neutral conditions ( Figure 2) to eq 7 supports the proposed mechanism.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The goodness of the data fit to eq 7, where the parameters a and d include a first-order reaction dependence on [SO] and [NBP], while the parameter b includes a first-order dependence on [NBP], reveals that the formation of the αand β-adducts occurs through S N 2′ and S N 2 mechanisms, as expected. 6 This, together with the preference of SO for the N7-position of guanine over other nucleophile positions of the DNA bases, 7,8,13,18,27 suggests that NBP is a suitable model to investigate the reactivity of SO with DNA. 21 The good fitting of the experimental A AD /t data obtained under neutral conditions (Figure 2) to eq 7 supports the proposed mechanism.…”

Section: ■ Introductionmentioning

confidence: 99%

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Alkylating Potential of Styrene Oxide: Reactions and Factors Involved in the Alkylation Process

González‐Pérez

Gómez‐Bombarelli

Pérez‐Prior

et al. 2014

Chem. Res. Toxicol.

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The chemical reactivity of styrene-7,8-oxide (SO), an alkylating agent with high affinity for the guanine–N7 position and a probable carcinogen for humans, with 4-(p-nitrobenzyl)pyridine (NBP), a trap for alkylating agents with nucleophilic characteristics similar to those of DNA bases, was investigated kinetically in water/dioxane media. UV–vis spectrophotometry and ultrafast liquid chromatography were used to monitor the reactions involved. It was found that in the alkylation process four reactions occur simultaneously: (a) the formation of a β-NBP–SO adduct through an SN2 mechanism; (b) the acid-catalyzed formation of the stable α-NBP–SO adduct through an SN2′ mechanism; (c) the base-catalyzed hydrolysis of the β-adduct, and (d) the acid-catalyzed hydrolysis of SO. At 37.5 °C and pH = 7.0 (in 7:3 water/dioxane medium), the values of the respective reaction rate constants were as follows: kalkβ = (2.1 ± 0.3) × 10–4 M–1 s–1, kalkα = (1.0 ± 0.1) × 10–4 M–1 s–1, khydAD = (3.06 ± 0.09) × 10–6 s–1, and khyd = (4.2 ± 0.9) × 10–6 s–1. These values show that, in order to determine the alkylating potential of SO, none of the four reactions involved can be neglected. Temperature and pH were found to exert a strong influence on the values of some parameters that may be useful to investigate possible chemicobiological correlations (e.g., in the pH 5.81–7.69 range, the fraction of total adducts formed increased from 24% to 90% of the initial SO, whereas the adduct lifetime of the unstable β-adduct, which gives an idea of the permanence of the adduct over time, decreased from 32358 to 13313 min). A consequence of these results is that the conclusions drawn in studies addressing alkylation reactions at temperatures and/or pH far from those of biological conditions should be considered with some reserve.

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Section: ■ Introductionmentioning

confidence: 57%

Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Alkylating Potential of Styrene Oxide: Reactions and Factors Involved in the Alkylation Process

González‐Pérez

Gómez‐Bombarelli

Pérez‐Prior

et al. 2014

Chem. Res. Toxicol.

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“…AIoir and coworkers (10, 33) have pointed out that ring opening a t C3 in the l-alkox~~-2,3-epox~~c~~clohexanes is to be expected if it is recognized that boncl-breaking is more important than bond-making in the transition state of SN2 epoxide scissions (34)(35)(36)(37) and that the electron-withdrawing effect of the alkoxyl group predominates over steric factors. This interpretation predicts inajor attack a t C3, but not exclusive (1, 2, 10) opening a t that point, since some of the experiments which led to its evolution (35-37) gave mixtures containing large amounts of ison~eric products.…”

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confidence: 99%

Cyclohexane Compounds: V. The Reaction of 1-Methoxycyclohexene-2 With Aqueous N-Bromosuccinimide. The 1-Methoxy-2-Bromo-3-Hydroxycyclohexanes

Bannard¹,

Casselman²,

Hawkins³

1965

Can. J. Chem.

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Interaction of 1-methoxycyclohexene-2 and aqueous N-bromosuccinimide gave a mixture of stereoisomeric bromohydrins, which, on treatment with aqueous sodium hydroxide, furnished 1~-methoxy-2a,3a-epoxycyclohexane (I) and la-methoxy-2a,3a-epoxycyclohexane (11) in the ratio 3: 1. The mixture from the N-haloimide-olefin reaction was separated by preparative vapor phase chromatography into three isomeric bromohydrins, la-methoxy-2a-hydroxy-3B-bromocyclohexane (IV), la-methoxy-2a-bromo-3B-hydroxycyclohexane (V), and la-methoxy-2B-bromo-3a-hydroxycyclohexane (VI) in the relative proportions 1:10:4. The 3-bromo isomer IV was identified by comparison with an authentic specimen prepared by the action of hydrobromic acid on the oxide 11. Compounds V and VI were shown to have the indicated structures by deetherification to the corresponding bromodiols VII and VIII in high yield, followed by debromination of the latter to trafzs-and cis-1,3-cyclohexanediol respectively. T h e product distribution is considered in relation to the intervention of electronic and steric factors in a possible mechanism suggested for the reaction between aqueous N-bron~osuccinimide and 1-methoxycyclohewne-2.Several years ago (1) we reported that the action of hydrobroinic acid on the stereoisoineric 1-methoxy-2,3-epoxycyclohexanes I and I1 led t o the formation of la-methoxy-2P-hydroxy-3a-bromocyclohexane (111) and 1a-n~ethoxy-2a-hydroxy-3~-broinocyclohexane (IV) respectively. The structures of these substances were established by a variety of chemical means (1) because we wished t o determine their relationship t o the mixture of bromohydrins resulting froin the action of aqueous N-broinosuccinimide upon l-inethoxycyclohexene-2. The latter bromohydrin mixture furnishes the oxides I and I1 in the ratioof 3 : l on treatment with aqueous sodium hydroxide and since 1,2-halohydrin t o oxide conversions involve a trans ring closure (3,4), it is apparent that the trans oxide I could have arisen from either or both of la-methoxy-2P-hydroxy-3a-brornocyclohexane (111) and la-methoxy-2a-bromo-3p-hydroxycyclohexane (V). Likewise the cis-oxide I1 wouId be formed if the mixture contained either la-methoxy-2a-hydroxy-3P-bromocyclol~exane (IV) or 1a-t~~ethoxy-2~-bromo-3a-hydroxycyclohexane (VI) or both. The present coinrnunication describes the manner in which the conlposition of the bronlohydrin mixture from the olefin-N-haloirnide reaction was determined and provides an unequivocal proof of structure for 1a-methoxy-2a-bromo-3~-hydroxycyclohexane (V) and la-n1etlloxy-2P-brorno-3a-h~.droxycyclohexane (VI).Attempts t o separate the components of the bromohydrin mixture by fractional distillation i n vacz~o and by coluinn chronlatography on alumina were unsuccessful. We therefore explored chemical separations based upon the forillation of crystalline derivatives. In this connection, the possible utility of acetate, p-toluenesulfonate, 2,4-dinitrobenzenesulfenate, dichloroacetate, 3-nitrophthalate, phenylurethane, and naphthylurethane derivatives was examine...

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Étard Reaction

2010

Comprehensive Organic Name Reactions and Reagents

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The oxidation of hydrocarbons by hexavalent chromium compounds (chromyl chloride, i.e., chromatic acid chloride) to form a mixture of alcohol, carbonyl compounds (aldehyde or ketones), chloro‐ketones, or aldehydes and the starting material is generally known as the Étard reaction. It has been observed the carbonyl compound functions as a ligand in the Étard complex and can be displaced by other coordinating solvents. The wide distribution of products and the lack of specificity at the reaction site reduce the yields of the desired compounds. As a result, this reaction is not a suitable reaction for organic synthesis, and the corresponding reaction mechanism is not clear, either.

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The Mechanism of Epoxide Reactions. IV.¹ The Reactions of Benzylamine with a Series of m- and p-Substituted Styrene Oxides in Ethanol²

Cited by 27 publications

References 0 publications

Alkylating Potential of Styrene Oxide: Reactions and Factors Involved in the Alkylation Process

Alkylating Potential of Styrene Oxide: Reactions and Factors Involved in the Alkylation Process

Cyclohexane Compounds: V. The Reaction of 1-Methoxycyclohexene-2 With Aqueous N-Bromosuccinimide. The 1-Methoxy-2-Bromo-3-Hydroxycyclohexanes

Étard Reaction

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The Mechanism of Epoxide Reactions. IV.1 The Reactions of Benzylamine with a Series of m- and p-Substituted Styrene Oxides in Ethanol2

Cited by 27 publications

References 0 publications

Alkylating Potential of Styrene Oxide: Reactions and Factors Involved in the Alkylation Process

Alkylating Potential of Styrene Oxide: Reactions and Factors Involved in the Alkylation Process

Cyclohexane Compounds: V. The Reaction of 1-Methoxycyclohexene-2 With Aqueous N-Bromosuccinimide. The 1-Methoxy-2-Bromo-3-Hydroxycyclohexanes

Étard Reaction

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The Mechanism of Epoxide Reactions. IV.¹ The Reactions of Benzylamine with a Series of m- and p-Substituted Styrene Oxides in Ethanol²