On Fructosazone Regiochemistry
Francisco Sánchez-Viesca,
Reina Gómez
Issue:
Volume 4, Issue 1, February 2016
Pages:
1-5
Received:
20 January 2016
Accepted:
28 January 2016
Published:
19 February 2016
Abstract: The regiochemistry observed in fructosazone has not been explained by other authors. A novel reaction mechanism has been provided in order to explain the regioselectivity leading to the fructosazone molecule. Our proposal and subsequent reactions are in agreement with the experimental facts and with well known reactivities. So, we have eliminated the existing gap between fact and theory. Many years have elapsed before an answer was given at last.
Abstract: The regiochemistry observed in fructosazone has not been explained by other authors. A novel reaction mechanism has been provided in order to explain the regioselectivity leading to the fructosazone molecule. Our proposal and subsequent reactions are in agreement with the experimental facts and with well known reactivities. So, we have eliminated t...
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Effect of Silver(I) Catalyst on the Oxidation of L-asparagine by Alkaline Hexacyanoferrate(III): A Kinetic and Mechanistic Approach
Ahmed Fawzy,
Ishaq Zaafarany,
Ameena Al-Bonayan,
Zakiya Al-Mallah,
Reem Shah
Issue:
Volume 4, Issue 1, February 2016
Pages:
6-15
Received:
28 January 2016
Accepted:
8 February 2016
Published:
25 February 2016
Abstract: The kinetics of oxidation of L-asparagine (Asn) by hexacyanoferrate(III) (HCF) has been investigated in alkaline medium in the absence and presence of silver(I) catalyst at a constant ionic strength of 0.5 mol dm−3 and at 20°C. The progress of both uncatalyzed and silver(I)-catalyzed oxidations was followed spectrophotometrically. Both reactions showed a first order dependence with respect to [HCF], whereas the orders with respect to [Asn] and [OH−] were less than unity. The catalyzed reaction exhibited a first order dependence in [AgI]. Increasing both ionic strength and dielectric constant of the reaction medium increased the rate of uncatalyzed reaction and did not affect significantly the rate of catalyzed reaction. Addition of the reaction product, HCF(II) to the reaction mixture had no affect on the rate. Appropriate reaction mechanisms for both uncatalyzed and catalyzed oxidations explaining all of the observed kinetic results has been proposed. The catalyzed reaction has been shown to proceed via formation of a silver(I)-asparagine intermediate complex, which reacted with the oxidant by an inner-sphere mechanism leading to decomposition of the complex in the rate-determining step to yield the final oxidation products which were identified as α-formyl acetamide, ammonia, and carbon dioxide. The rate law expressions associated with the reaction mechanisms were derived.
Abstract: The kinetics of oxidation of L-asparagine (Asn) by hexacyanoferrate(III) (HCF) has been investigated in alkaline medium in the absence and presence of silver(I) catalyst at a constant ionic strength of 0.5 mol dm−3 and at 20°C. The progress of both uncatalyzed and silver(I)-catalyzed oxidations was followed spectrophotometrically. Both reactions sh...
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