Nucleophilic Reactivity of Alkoxide Ions Towards 2,4-Dinitrofluorobenzene and the Acidity of Alcohols.

Murto, Juhani; Sandström, Jan; Toplin, I.; Melera, A.; Nilsson, Lennart

doi:10.3891/acta.chem.scand.18-1043

Cited by 65 publications

(32 citation statements)

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“…Of the two proposed fGly catalyzed pathways, the S N 2-E2 mechanism requires only one high energy barrier S-O bond cleavage. The rate of the initial S N 2 step may be accelerated by the decreased p K a of the geminal diol hydroxyl group (e.g., acetaldehyde hydrate has a p K a of 13.57 33 ) compared to a conventional hydroxyl group (e.g., 15.93 34 ). A recent theoretical study has suggested that the initial nucleophilic attack of fGly-diol on substrate may be rate-determining, and not the subsequent elimination.…”

Section: Fgly Participates Directly In Sulfate Ester Hydrolysismentioning

confidence: 99%

Formylglycine, a Post-Translationally Generated Residue with Unique Catalytic Capabilities and Biotechnology Applications

2014

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Formylglycine (fGly) is a catalytically essential residue found almost exclusively in the active sites of type I sulfatases. Formed by post-translational oxidation of cysteine or serine side chains, this aldehyde-functionalized residue participates in a unique and highly efficient catalytic mechanism for sulfate ester hydrolysis. The enzymes that produce fGly, formylglycine-generating enzyme (FGE) and anaerobic sulfatase-maturating enzyme (anSME), are as unique and specialized as fGly itself. FGE especially is structurally and mechanistically distinct, and serves the sole function of activating type I sulfatase targets. This review summarizes the current state of knowledge regarding the mechanism by which fGly contributes to sulfate ester hydrolysis, the molecular details of fGly biogenesis by FGE and anSME, and finally, recent biotechnology applications of fGly beyond its natural catalytic function.

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Section: Fgly Participates Directly In Sulfate Ester Hydrolysismentioning

confidence: 99%

Formylglycine, a Post-Translationally Generated Residue with Unique Catalytic Capabilities and Biotechnology Applications

2014

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“…Ethyl iodide should be less reactive with the organic-inorganic carbonate hybrid than methyl iodide, according to the SN 2 mechanism. There is greater steric hindrance with ethyl iodide and the electrophilic character of the alkyl group of ethyl iodide dissolved in ethanol is less marked than that of methyl iodide dissolved in methanol, due to the lower dissociation power of ethanol than of methanol [31]. However, the mixture of ethanol and ethyl iodide is swollen [40] by the CO 2 , increasing the reactivity of the different species, for example, the reactivity of EtOH with CO 2 and that of PEC with EtI.…”

Section: Carbon Dioxide Sequestration Into An Organic Carbonatementioning

confidence: 99%

“…For these reasons, carbon dioxide sequestration with ethanol is in keeping with most green chemistry principles. However, ethanol is less reactive than methanol, as it is less acidic [31].…”

Section: Introductionmentioning

confidence: 99%

Methods for synthesizing diethyl carbonate from ethanol and supercritical carbon dioxide by one-pot or two-step reactions in the presence of potassium carbonate

Gasc

Thiébaud‐Roux

Mouloungui

2009

The Journal of Supercritical Fluids

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Carbon dioxide sequestration was studied by synthesizing diethyl carbonate (DEC) from ethanol and CO 2 under supercritical conditions in the presence of potassium carbonate as a base. The co-reagent was ethyl iodide or a concentrated strong acid. This sequestration reaction occurs in two steps, which were studied separately and in a one-pot reaction. An organic-inorganic carbonate hybrid, potassium ethyl carbonate (PEC) is generated at the end of the first step. This intermediate was characterized and was found to be a target molecule for CO 2 capture. Different co-reactants, such as ethyl iodide and concentrated strong Brönsted acid, were compared in the second step and used to investigate the reactivity of the hybrid. With ethyl iodide as the co-reactant, one-pot DEC synthesis gave higher yields (46%) than two-step production. The supercritical CO 2 acts as a swelling solvent and compatibilizing agent in the reaction medium, favoring interactions between ethanol and CO 2 and between PEC and ethyl iodide. The use of a phase transfer catalyst (PTC) increased DEC production (yield 51%) without increasing the amount of diethyl ether (DEE) produced as a by-product (yield 2%).

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“…Keto acids and hydroxyketones have the potential to engage in ring‐chain tautomerism. When the intramolecular nucleophilic attack of the carboxyl group in the keto acid at the carbonyl carbon occurs in the tautomerism (Figure b), the deprotonation of H4 in the inflexible ring can be caused by the influence on the production of the hemiketal due to the high p K a value for the alcohols (12–19). These interpretations are related to the mechanisms in the presence of base.…”

Section: Resultsmentioning

confidence: 99%

The Multiple Reactions in the Monochlorodimedone Assay: Discovery of Unique Dehalolactonizations under Mild Conditions

2015

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The monochlorodimedone assay hasb een widely used as an assayo ft he brominating activity of halogenating enzymes;h owever, the assumed product was found to spontaneously decompose during the measurement. The decompositionm echanism and systematic error in the assay were explained by five reactions in their multiple reactions.We discoveredu nique dehalolactonizations of halogenated d-keto acids in aqueous solutiona mong many reactions in the assay.I ts reactionm echanism wass uggested as the cyclization via ac yclopropanone intermediate produced by the intramolecular catalysis of the carboxylate anion. Figure 1. (a) MCD assay and (b) caldoriomycin biosynthesis.[a] H.

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Nucleophilic Reactivity of Alkoxide Ions Towards 2,4-Dinitrofluorobenzene and the Acidity of Alcohols.

Cited by 65 publications

References 0 publications

Formylglycine, a Post-Translationally Generated Residue with Unique Catalytic Capabilities and Biotechnology Applications

Formylglycine, a Post-Translationally Generated Residue with Unique Catalytic Capabilities and Biotechnology Applications

Methods for synthesizing diethyl carbonate from ethanol and supercritical carbon dioxide by one-pot or two-step reactions in the presence of potassium carbonate

The Multiple Reactions in the Monochlorodimedone Assay: Discovery of Unique Dehalolactonizations under Mild Conditions

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