Kinetics and mechanism of the hydrolysis of N-isobutylidenemethylamine in aqueous solution

Hine, Jack; Craig, J. Cymerman; Underwood, J. G.; Via, Francis A.

doi:10.1021/ja00720a032

Cited by 72 publications

(34 citation statements)

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“…This means that the difference between the free energy of transfer of enamine and imine pairs will be the same for all cases. This clearly is only an approximation, yet should be close because absent steric bulk which causes shielding from solvent the only difference is in the distant polar interactions which are not expected to be very different; the pKa value of the two nitrogens should be similar since a simple imine has a pKa of about 7 (7.6 for N-isopropylidenemethylamine (57), 6.88 for E-N-isobutylidenemethylamine (58)) and an enamine is expected to have pKa similar to aniline, i.e., 4.58 (44) (just as an enol (e.g., vinyl alcohol, pKa 10.50 (59)) has a pKa similar to a phenol (phenol itself, pKa 9.95 (44))). This means that the equilibrium constant for imine-enamine conversion in solution can be calculated from the equilibrium constant in the gas using only this roughly constant difference in free energies of transfer.…”

Section: Resultsmentioning

confidence: 99%

Uncatalyzed and Amine Catalyzed Decarboxylation of Acetoacetic Acid: An Examination in Terms of No Barrier Theory

Guthrie

2002

Bioorganic Chemistry

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Section: Resultsmentioning

confidence: 99%

Uncatalyzed and Amine Catalyzed Decarboxylation of Acetoacetic Acid: An Examination in Terms of No Barrier Theory

Guthrie

2002

Bioorganic Chemistry

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“…When antigens loaded on sNC are taken up into a vesicle of APCs through endocytosis, the vesicle fuses with endosomes and pH drops to around 5–5.5 in late endosome (Geisow & Evans, ). Since protonation of imine occurs around pH 5 (Hiñe, Craig, Underwood, & Via, ), pH drop in the late endosome may initiate hydrolysis and cleave the bonding. Released antigens could transfer to cytoplasm through protein translocation channels such as the Sec61 complex, endosome escape of carriers and antigens, and fusion with the endoplasmic reticulum, which led to presentation via MHC Class I (Burgdorf & Kurts, ).…”

Section: Discussionmentioning

confidence: 99%

Sustained‐immunostimulatory nanocellulose scaffold to enhance vaccine efficacy

Nishiguchi

Taguchi

2020

J Biomedical Materials Res

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An implantable scaffold‐based vaccination system is a promising platform to generate robust immune responses by modulating the immune system. However, establishment of an effective vaccine using a biodegradable, cell‐infiltrative scaffold remain challenging. Here we demonstrate a biodegradable, nanocellulose‐based immune scaffold capable of sustainably activating immune cells to elicit cellular immunity. Cell‐infiltrative nanocellulose hydrogels were used as a delivery carrier and cellular scaffold microenvironment. Nanofibrous hydrogels allowed for high cell infiltration and delivery of antigen‐loaded nanocellulose while cells degraded the hydrogel matrix. Importantly, antigen‐loaded nanocellulose hydrogels exhibited sustained activation of macrophages in vitro compared to free antigen and collagen scaffold. Histological observation revealed infiltration of macrophages and dendritic cells into the nanocellulose scaffold subcutaneously implanted in mice. In vivo fluorescence imaging indicated that the implanted scaffold released antigens at a zero‐order release profile without burst diffusion. Antigen‐loaded nanocellulose hydrogels increased interferon‐γ‐producing cells compared to free antigen injection, suggesting the enhancement of cellular immunity. Thus, nanocellulose immune scaffold may serve as a sustained‐immunostimulatory vaccine platform by providing favorable microenvironments for immune cells thus enhancing vaccine efficacy.

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“…The effect of the p-chloro is taken from a Hammett correlation for benzylamines (26), ApK, = 0.25. The effect of the carbinolamine OH is taken as the average value recommended by Hine, ApK, = 1.88 (27). These corrections lead to a pK, of 1.66 for the NH of the protonated carbinolamine.…”

Section: Multidimensional Marcus Theorymentioning

confidence: 99%

The tetrahedral intermediate from the hydration of N-methylformanilide

Guthrie¹,

Barker²,

Cullimore³

et al. 1993

Can. J. Chem.

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. Can. J. Chem. 71, 2109Chem. 71, (1993.Heats of hydrolysis of N-methylformanilide dimethyl acetal have been measured in basic solution. The heat of formation of N-methylformanilide was obtained by determining the equilibrium constant in aqueous solution for its formation from formic acid and N-methylaniline as a function of temperature: m : (~) = -33.78 * 1.85 kcal/mol. These data permit the calculation of the heat of formation of N-methylfonnanilide dimethyl acetal, AH;(l) = -72.95 * 1.85 kcal/mol. The free energy of formation of the tetrahedral intermediate in the hydrolysis of N-methylformanilide was calculated by methods we have previously reported. Consideration of the energetics of the intermediates and the known rates of reaction leads to the conclusion that the rate-determining step for alkaline hydrolysis is cleavage of the C-N bond. Operant en solution basique, on a mesurC les chaleurs d'hydrolyse l'acktal dimkthylique de la N-mCthylformanilide. On a obtenu la chaleur de formation de la N-mCthylformanilide en determinant la constante d'kquilibre en fonction de la temperature (en solution aqueuse) pour sa formation 2 partir de l'acide formique et la N-methylaniline: m;(1) = -33,78 * 1,85 kcal/mol. Ces donnCes permettent de calculer la chaleur de formation de I'acCtal dimkthylique de la N-mCthylformanilide, mY(1) = -72,95 * 1,85 kcal/mol. Utilisant des methodes dkcrites anterieurement, on a calculC 1'Cnergie libre de formation de I'intermCdiaire tCtraCdrique implique dans l'hydrolyse de la N-mCthylformanilide. Une considCration des energies des intermediaires et des constantes de vitesse connues mkne i la conclusion que 1'Ctape qui dktermine la vitesse de la reaction de l'hydrolyse alcaline est le clivage de la liaison C-N.[Traduit par la redaction]

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Kinetics and mechanism of the hydrolysis of N-isobutylidenemethylamine in aqueous solution

Cited by 72 publications

References 0 publications

Uncatalyzed and Amine Catalyzed Decarboxylation of Acetoacetic Acid: An Examination in Terms of No Barrier Theory

Uncatalyzed and Amine Catalyzed Decarboxylation of Acetoacetic Acid: An Examination in Terms of No Barrier Theory

Sustained‐immunostimulatory nanocellulose scaffold to enhance vaccine efficacy

The tetrahedral intermediate from the hydration of N-methylformanilide

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