20902-45-8Relevant articles and documents
Penicillamine and captopril: mechanistic exploration of defensive actions of thiol drugs against a metal bound-superoxo complex
Mandal, Arabinda,Das, Ranendu Sekhar,Singh, Bula,Banerjee, Rupendranath,Mukhopadhyay, Subrata
, p. 1723 - 1738 (2017)
In acid-media ([H+]?=?0.01–0.06?M), each of the thiol compounds, D-penicillamine (PEN, LPH2) and captopril (CAP, LCH2) exist in several proton-dependent forms which can reduce the superoxo complex [(en)(dien)CoIII(O2)CoIII(en)(dien)]5+ (1) to the corresponding peroxo [(en)(dien)CoIII(O2)CoIII(en)(dien)]4+ (2) or the hydroperoxo complex [(en)(dien)CoIII(OOH)CoIII(en)(dien)]5+ (3). The observed first-order rate constants, k o,P and k o,C for PEN and CAP increase with the increase in [TPEN] and [TCAP] (which are the analytical concentrations of the respective thiols) but decrease with the increase in the media-acidity ([H+]) and the media ionic strength (I). The protolytic equilibria in aqueous solution allow several potentially reducing forms to coexist for both PEN (LPH3 +, LPH2, LPH?, and LP 2?) and CAP (LCH2, LCH?, LC 2?) but the kinetic analyses reveal that the order of reactivity for the species are LPH3 + ~ LPH2?PH? and LCH2?CH??C 2?, respectively. The predominance and higher reactivities of the anionic species, LPH? and LC 2? are supported by the negative slopes of the plots of k o,P or k o,C versus I. Moreover, a large value of k H/k D for PEN suggests an inner-sphere electroprotic reaction pathway while the absence of such effect for CAP strongly supports an outer-sphere electron transfer reaction. These propositions are supported by the structural features of LPH? and LC 2?.
Mechanistic scrutiny of the oxidations of thiol-containing drugs cysteamine and d-penicillamine by cis-diamminetetrachloroplatinum(IV)
Zhou, Li,Li, Tiejian,Sun, Ying,Tian, Hongwu,Gao, Cunxiu,Liu, Chunli,Kong, Lingli,Zhang, Guimin,Shi, Tiesheng
, p. 548 - 557 (2021)
Cysteamine (CA) and d-penicillamine (Pen) are the thiol-containing drugs and good antioxidants. Their reactions with a cisplatin Pt(IV) prodrug cis-diamminetetrachloroplatinum(IV) (cis-[Pt(NH3)2Cl4]) were investigated by use of rapid scan, stopped-flow, and mass spectral techniques. The kinetic traces are biphasic in nature, encompassing a faster reduction of cis-[Pt(NH3)2Cl4] to cisplatin followed by slow substitutions on cisplatin. The reduction reactions were demonstrated to follow overall second-order kinetics over a wide pH range. The observed second-order rate constants versus pH profiles were established at 25.0°C and 1.0?M ionic strength, indicating a huge increase of reaction rate with the increase of pH. However, the oxidations of CA and Pen by cis-[Pt(NH3)2Cl4] displayed different reaction stoichiometric ratios as revealed by the spectrophotometric titration experiments. Accordingly, CA was oxidized to CA-disulfide while Pen-sulfinic acid and Pen-disulfide were identified as the major products in the case of Pen via mass spectral analysis. The above similarities and differences are rationalized in terms of the proposed reaction mechanisms, which encompass similar rate-determining reactions for both CA and Pen, but involve disparate and faster followed-up reactions. Rate constants of the rate determining were derived at 25.0°C and 1.0?M ionic strength. A consequent species reactivity analysis revealed that the species -SCH2CH2NH3+ of CA and the species +H3NCH(COO?)CMe2S? of Pen played a predominant role toward the reduction of cis-[Pt(NH3)2Cl4] from pH 5 to 8, which also is a critical pH region for most of drugs.
The trans opening of ethylene diamine tetra acetic acid bis anhydride (EDTAA) with cystine-di-OMe: One-step synthesis of bihelical systems Respectfully dedicated to Professor M.V. George on the occasion of his 85th birthday
Naini, Santhosh Reddy,Ranganathan, Subramania,Yadav, Jhillu Singh,Sarma,Ramakrishna,Nagaraj, Ramakrishnan,Premkumar, J. Richard,Sastry, G. Narahari
, p. 1132 - 1135 (2014/02/14)
The generation of a bihelical (figure of 8) motif has been illustrated by trans opening of EDTAA with l-cystine-di-OMe and d-penicillamine disulfide-di-OMe. In the former case the open cyclic system, arising by cis addition, was secured as a minor product.
