7181-87-5Relevant articles and documents
N,N-Dialkylbenzimidazol-2-ylidene platinum complexes-effects of alkyl residues and ancillary cis-ligands on anticancer activity
Rehm, Tobias,Rothemund, Matthias,B?r, Alexander,Dietel, Thomas,Kempe, Rhett,Kostrhunova, Hana,Brabec, Viktor,Kasparkova, Jana,Schobert, Rainer
, p. 17367 - 17381 (2018)
Eleven complexes of [(1,3-dialkylbenzimidazol-2-ylidene)LnCl3?n]Pt(n?1)+, with Ln = DMSO (8), Ph3P (9), (Ph3P)2 (10), and alkyl = Me (a), Et (b), Bu (c), octyl (d), were synthesised and tested for cellular accumulation, cytotoxicity, interference with the tumour cell cycle, and interaction with DNA. The delocalised lipophilic cationic bisphosphane complexes 10 were on average found to be more cytotoxic in MTT assays against a panel of seven cancer cell lines than the neutral DMSO and monophosphane complexes 8 and 9. The uptake of complexes 10, at least into HCT116 colon carcinoma cells, was also significantly greater than that of analogues 8 and 9. Their cytotoxicities did not differ significantly with the N-alkyl side chain length. The complexes that were most active, with sub-micromolar IC50 (72 h) values against HCT116wt cells, that is 8b, 9b, 10a-c, worked by a mode of action that was dependent on the functional p53, yet were still far more active than cisplatin in both of the HCT116wt and HCT116?/? variants. In detailed binding analyses 8c, 9c and 10a-c showed a lower affinity to DNA and different binding modes when compared to cisplatin, preferably forming mono-adducts with DNA and distorting it to a lower extent. Also, unlike cisplatin, they arrested the HCT116 cells of both variants predominantly in the G1 phase.
Benzimidazol-2-ylidene gold(I) complexes are thioredoxin reductase inhibitors with multiple antitumor properties
Rubbiani, Riccardo,Kitanovic, Igor,Alborzinia, Hamed,Can, Suzan,Kitanovic, Ana,Onambele, Liliane A.,Stefanopoulou, Maria,Geldmacher, Yvonne,Sheldrick, William S.,Wolber, Gerhard,Prokop, Aram,W?lfl, Stefan,Ott, Ingo
, p. 8608 - 8618 (2010)
Gold(I) complexes such as auranofin have been used for decades to treat symptoms of rheumatoid arthritis and have also demonstrated a considerable potential as new anticancer drugs. The enzyme thioredoxin reductase (TrxR) is considered as the most relevan
Formation and Stability of N-Heterocyclic Carbenes in Water: The Carbon Acid pKa of Imidazolium Cations in Aqueous Solution
Amyes, Tina L.,Diver, Steven T.,Richard, John P.,Rivas, Felix M.,Toth, Krisztina
, p. 4366 - 4374 (2004)
We report second-order rate constants kDO (M-1 s -1) for exchange for deuterium of the C(2)-proton of a series of simple imidazolium cations to give the corresponding singlet imidazol-2-yl carbenes in D2O at 25 °C and l = 1.0 (KCl). Evidence is presented that the reverse protonation of imidazol-2-yl carbenes by solvent water is limited by solvent reorganization and occurs with a rate constant of kHOH = kreorg = 1011 s-1. The data were used to calculate reliable carbon acid pKas for ionization of imidazolium cations at C(2) to give the corresponding singlet imidazol-2-yl carbenes in water: pKa = 23.8 for the imidazolium cation, pK a = 23.0 for the 1,3-dimethylimidazolium cation, pKa = 21.6 for the 1,3-dimethylbenzimidazolium cation, and pKa = 21.2 for the 1,3-bis-((S)-1-phenylethyl)benzimidazolium cation. The data also provide the thermodynamic driving force for a 1,2-hydrogen shift at a singlet carbene: K12 = 5 × 1016 for rearrangement of the parent imidazol-2-yl carbene to give neutral imidazole in water at 298 K, which corresponds to a favorable Gibbs free energy change of 23 kcal/mol. We present a simple rationale for the observed substituent effects on the thermodynamic stability of N-heterocyclic carbenes relative to a variety of neutral and cationic derivatives that emphasizes the importance of the choice of reference reaction when assessing the stability of N-heterocyclic carbenes.
Kinetic analysis of the complete mechanochemical synthesis of a palladium(II) carbene complex
Allenbaugh, Rachel J.,Zachary, Jonathon R.,Underwood, A. Nicole,Bryson, J. Dillion,Williams, Joseph R.,Shaw, Angela
, (2019/12/03)
Benzimidazoline-2-ylidene complexes of palladium(II) were synthesized mechanochemically in a vibratory ball mill. Complete syntheses began with preparation of benzimidiazolium halides from commercially available starting materials. These “greener chemistr
Neutral Organic Super Electron Donors Made Catalytic
Rohrbach, Simon,Shah, Rushabh S.,Tuttle, Tell,Murphy, John A.
supporting information, p. 11454 - 11458 (2019/07/18)
Neutral organic super electron donors (SEDs) display impressive reducing power but, until now, it has not been possible to use them catalytically in radical chain reactions. This is because, following electron transfer, these donors form persistent radical cations that trap substrate-derived radicals. This paper unlocks a conceptually new approach to super electron donors that overcomes this issue, leading to the first catalytic neutral organic super electron donor.
