Osmium(VIII) Catalyzed Oxidative Cleavage of Pyrrolidine Ring in l-Proline by Hexacyanoferrate(III) in Alkaline Media

Abstract

Kinetics of oxidation of L-proline by hexacyanoferrate(III) catalyzed by osmium(VIII) in alkaline medium was studied at 30°C. A mechanism involving free radical path was proposed. Rate law of the reaction was derived asThe rate constant k and equilibrium constants K 1 and K 2 were evaluated as 3.79 × 10 3 dm 3 mol -1 s -1 , 0.52 dm 3 mol -1 , and 3.78 × 10 3 dm 3 mol -1 , respectively. The main reactive species of the catalyst appears to be OsO 5 (OH) 3-. The oxidative product of L-proline was identified as L-glutamic acid which is different from the earlier reports. The literature reveals that 4-amino butyric acid, 4-amino butaraldehyde and keto acids were the oxidative products. Activation parameters were evaluated as E a ) 33.5 ( 2 kJ mol -1 , ∆H q ) 31.0 ( 0.2 kJ mol -1 , ∆S q ) -24 ( 1.5 J K -1 mol -1 , ∆G q ) 38.0 ( 2 kJ mol -1 .

Kinetics and Mechanism of Ruthenium(III) Catalyzed Oxidation of LProline by Hexacyanoferrate(III) in Aqueous Alkali

“…Oxidation of L-proline by alkaline hexacyanoferrate(III) in ruthenium(III) was followed without intervention of free radicals, whereas in Osmium(VIII) catalysis [29], the oxidation was occurred through intervention of free radicals. Hence, mechanism proposed for both the studies are different.…”

Kinetic and Mechanism of Oxidation of Methylaminopyrazole Formamidine by Alkaline Hexacyanoferrate(III) and the Effect of Divalent Transition Metal Ions

“…Oxidation of organic compounds by hexacyanoferrate(III) as an efficient one-electron oxidant has been a subject of much interest especially in alkaline media [6][7][8][9][10][11][12][13][14][15][16][17]. The usefulness of HCF may be due to its high stability, water solubility and its moderate reduction potential of 0.45 V, leading to its reduction to HCF(II), a stable product [18].…”

“…On the other hand, complexes of metal ions with organic ligands containing N, S or O are well known [13][14][15][16][17]. The presence of heteroatom in such ligands plays a key role when coordinated with transition metal ions.…”

Mechanistic investigation of the oxidation of Cefuroxime by hexacyanoferrate(III) in alkaline conditions

“…Hexacyanoferrate (III) (HCF(III)) ion in alkaline medium known to oxidise inorganic and organic compounds [17][18][19][20][21][22][23][24][25][26][27][28][29] HCF(III)/ HCF(II) is a one electron oxidant with a redox potential of +0.36 V [30]. It is a moderate oxidizing agent and therefore, is used as electron or proton abstracting agent and results in the formation of a free radical intermediate during the oxidation of organic compounds [31].…”