19692-45-6Relevant articles and documents
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Clement et al.
, p. 2449,2452 (1960)
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Fine-tuning of the pharmacological potential of novel thiazolium ionic liquids by anion alteration
Alfaifi, Mohammad Y.,Elbehairi, Serag Eldin I.,Elshaarawy, Reda F. M.,Gad, Emad M.,Shati, Ali A.
, p. 458 - 469 (2022/01/19)
A novel series of thiazolium ionic liquids (TILs) bound to chloride (2a-c), tetrafluoroborate (BF4) (3a-c), and bis-(trifluoromethanesulfonimide) (Tf2N) anions (4a-c) was synthesized and their physicochemical characteristics were investigated using various microanalytical techniques. The pharmacological potential of the new TILs was assessed as chemotherapeutic agents for bacterial infections and ovarian cancer (SKOV-3). Notably, ILs with the same cations become more bactericidal upon their binding with the strongest chaotropic anion (TN2f). The in vitro toxicity of the TILs toward ovarian carcinoma cell lines (SKOV-3) and normal human skin fibroblast cells (HSF) revealed that all tested TILs have the capacity to induce a dose- and time-dependent decline in SKOV-3 cell viability, with Tf2N-linked TILs (4a-c) having a preferable efficacy. In addition, the new compounds showed excellent selectivity for cancer cells (SKOV-3) over healthy cells (HSF). [iPBzTh][Tf2N] (4b) is the most cytotoxic and specific one and may act as a promising anti-ovarian cancer agent.
Lewis Base Catalysis Enables the Activation of Alcohols by means of Chloroformates as Phosgene Substitutes
Zoller, Ben,Stach, Tanja,Huy, Peter H.
, p. 5637 - 5643 (2020/09/21)
Nucleophilic substitutions (SN) are typically promoted by acid chlorides as sacrificial reagents to improve the thermodynamic driving force and lower kinetic barriers. However, the cheapest acid chloride phosgene (COCl2) is a highly toxic gas. Against this background, phenyl chloroformate (PCF) was discovered as inherently safer phosgene substitute for the SN-type formation of C?Cl and C?Br bonds using alcohols. Thereby, application of the Lewis bases 1-formylpyrroldine (FPyr) and diethylcyclopropenone (DEC) as catalysts turned out to be pivotal to shift the chemoselectivity in favor of halo alkane generation. Primary, secondary and tertiary, benzylic, allylic and aliphatic alcohols are appropriate starting materials. A variety of functional groups are tolerated, which includes even acid labile moieties such as tert-butyl esters and acetals. Since the by-product phenol can be isolated, a recycling to PCF with inexpensive phosgene would be feasible on a technical scale. Eventually, a thorough competitive study demonstrated that PCF is indeed superior to phosgene and other substitutes.
