Ascorbic acid acts as a hydride donor towards ­2‐arsonocarboxylic acids

Abstract

2-Arsonohexanoic acid is decomposed during its attempted reduction to 2-arsenosohexanoic acid by triphenylphosphine in the presence of a catalytic amount of iodine. When ascorbic acid is substituted for the triphenylphosphine, hexanoic acid is obtained, implying that the arscorbic acid acts as a hydride donor. Copyright #

Modified Carbon Paste Electrode for Kinetic Investigation and Simultaneous Determination of Ascorbic and Uric Acids

“…1B). The hydride route has been shown before by Siskos and coworkers in a similar way, where AscH 2 also acts as a hydride donor [27].…”

Preparation of 2-Picolylarsonic Acid and its Reductive Cleavage by Ascorbic Acid/Iodine and by Thiophenol

“…16 In the absence of iodine, equimolar amount of triphenylphosphine did not attack, as expected, 16 the substrate 2-picolylarsonic acid. In this, as in the case of 2-arsonohexanoic acid, 25 hydrogen-bonding to the OH group on C-2 thus forming a sixmembered ring in the activated complex and the As O − would abstract the proton from the acidic OH group on C-3. Since triphenylphosphine oxide was detected by TLC, then the 2-picolylarsenoso compound must have been formed and it was detected by 1 H-NMR [(ArCH 2 AsO) x : 3.46 ppm compared to (PhCH 2 AsO) x : 3.50 ppm 16 ].…”

“…Before being reduced, the AsO 3 H 2 group must be converted to an As + (OH) 2 OY species, either by H + or by Ph 3 P + OMe, and then the I − adds to As + to give a pentacoordinated intermediate. 25 When the polarity of the solvent increased (methanol/water 1:1 and water) then the decomposition was greatly inhibited. In its presence it reacted but very slowly indicating that the nitrogen on the substrate poisons the system.…”

“…In its presence it reacted but very slowly indicating that the nitrogen on the substrate poisons the system. 25 A still milder reducing agent for the AsO 3 H 2 and AsO 2 H groups is a thiol, which gives a dithioarsonite, R-As(SR ) 2 , 27 or thioarsinite, R 2 As-SR 28 respectively. Its amount was small.…”

Ascorbic Acid/Iodine and Triphenylphosphine/Iodine as Reducing Agents for the As(V)[dbnd]O Group

“…C As bond fission has, so far, been observed only during the reduction of 2-arsonohexanoic acid, which gave As 2 O 3 and hexanoic acid. 9 The reduction of arsinic acids, R 2 AsO 2 H, can lead to haloarsines, R 2 AsX, to bis(dialkyl)diarsines, R 2 As-AsR 2 , or to arsines, R 2 AsH, depending on the reducing agent. 7a There are no reports in the literature 10a on the direct reduction of arsinic acids to their oxides, R 2 As-O-AsR 2 , and the reduction of diphenylarsinic acid by phenylhydrazine gave Ph 3 As instead of Ph 2 As-O-AsPh 2 .…”