2-Imidazolidone: Synthesis and Application

2-Imidazolidone (Ethylene Urea) is a white crystalline powder that can be dissolved in water. It is a kind of formaldehyde scavenger. 2-Imidazolidone can be used as an anti-crease, de-aldehyde, and crosslinking agent. It's also the main component of air fresheners.

Synthesis of 2-Imidazolidone

A product according to the invention was prepared by the following procedure: 60.3 g (1 mol) of ethylenediamine (having a purity of 99.5%), 45.45 g (0.5 mol) of dimethyl carbonate (having a purity of 99 %), 92.93 g (1 mol) of toluene, and 4.5 g (0.025 mol) of a 30 % strength solution of sodium methoxide in methanol were charged to a reaction vessel under nitrogen purge and mixed at room temperature (23 °C). An exotherm was observed and temperature increase to 55 °C was recorded. After one hour, the temperature was increased to 90 °C and held for two hours at reflux. A white solid was formed upon cooling of the reaction mixture. The product was filtered and washed with toluene. The isolated 2-Imidazolidone product was analysed by 13C-NMR and found to be ethylene urea with purity of 97 %, with a mass fraction of water of 0.4 % as measured by Karl Fischer-titration. The mass fraction of residual ethylenediamine was found to be 150 mg/kg. The melting temperature of the ethylene urea formed was 135 °C. The yield was 90 %. Upon additional washing of 2-Imidazolidone with acetone, a product having a purity of 99.9 % and a mass fraction of residual ethylenediamine of 100 mg/kg was obtained. The product was a free-flowing solid.[1]

Inactivated horseradish peroxidase with 2-Imidazolidone and allantoin

A method for reactivation of inactivated horseradish peroxidase (HRP) with 2-Imidazolidone and allantoin was studied and exploited in a continuous assay of hydrogen peroxide by micro-flow injection HRP-catalyzed luminol chemiluminescence. It is necessary to maintain the activity of immobilized HRP constant during the assay of hydrogen peroxide because the HRP is used repeatedly. If no reactivating reagents are used (control), light emission from H2O2 (9.7 μmol l−1) decreased in the course of the assay resulting in poor reproducibility (CV=22.9%, n=3). However, if 2-Imidazolidone (100 mmol l−1) is added to the luminol solution (0.56 mmol l−1 in Tricine buffer, pH 9.2) the reproducibility of the assay improved remarkably (CV=2.9%, n=5). Allantoin (10 mmol l−1) also improved the reproducibility of the assay (CV=4.33%, n=10). However, a side effect was the suppression of light emission from H2O2 in a dose-dependent manner with both 2-Imi 2-Imidazolidone dazolidone and allantoin. The 3σ detection limit of H2O2 using 2-Imidazolidone (100 mmol l−1) was 0.6 pmol per injection. The mechanism of the inactivation of HRP after reaction with H2O2 and reactivation of the inactivated HRP was postulated as follows: the active site of HRP attracts a proton from H2O2 resulting in protonated HRP (inactive form). Exogenous 2-Imidazolidone or allantoin removes the proton attached at the active site of the protonated HRP to return the enzyme to the active form.[2]

Scientists investigated a method for reactivation of HRP with 2-Imidazolidone and allantoin for consecutive determinations of H2O2 by micro-flow injection HRP-catalyzed luminol chemiluminescence, and verified our postulate on the mechanism of reactivation and inactivation of HRP. Both 2-Imidazolidone and allantoin are five-membered nitrogen heterocyclics similar to imidazole. In this study, we show that the both 2-Imidazolidone and allantoin successfully reactivated inactivated HRP. Side effects of this substance on light emission from H2O2 were investigated. Light intensities from H2O2 samples (0.61, 1.22, 2.43, 4.85, and 9.7 μmol l−1) were suppressed in proportion to the concentration of 2-Imidazolidone (0, 5, 10, and 100 mmol l−1). 2-Imidazolidone (100 mmol l−1) suppressed the light intensities of H2O2 samples (0.61, 1.22, 2.43, 4.85, and 9.7 μmol l−1) to 58.3, 59.5, 65.7, 57.9, and 70.1% of those from H2O2 without 2-Imidazolidone (control), respectively. The same results were obtained with 10 and 5 mmol l−1 2-Imidazolidone, 10 mmol l−1 producing greater suppression than 5 mmol l−1.[3]

References

[1] Current Patent Assignee: ALLNEX BELGIUM - EP2548870, 2013, A1

[2] Nozaki, O., & Kawamoto, H. (2003). Reactivation of inactivated horseradish peroxidase with ethyleneurea and allantoin for determination of hydrogen peroxide by micro-flow injection horseradish peroxidase-catalyzed chemiluminescence. Analytica Chimica Acta, 495(1 - 2), 233 - 238.

[3] Nozaki, O., Iwaeda, T., & Kato, Y. (1996). Amines for detection of dopamine by generation of hydrogen peroxide and peroxyoxalate chemiluminescence. Journal of Bioluminescence and Chemiluminescence, 11(6), 309 - 313.

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