65881-41-6Relevant articles and documents
Effect of side chain structure on the conformation of poly(N-propargylalkylamide)
Nomura, Ryoji,Tabei, Junichi,Masuda, Toshio
, p. 2955 - 2961 (2002)
Achiral N-propargylalkylamides (1a-1g, HC≡CCH2NHR) having various alkyl groups (R = CH3, C2H5, C3H7, i-C3H7, i-C4H9, n-C5H11, n-C7H15) were homopolymerized or copolymerized with a chiral comonomer, (R)-N-propargyl-3,7-dimethyloctanamide (2), in the presence of a Rh initiator to establish the relationship between the main-chain conformation and the structure of the pedant groups. 1H NMR and viscosity measurements of the homopolymers revealed that the structure of the pendant groups markedly influences the rigidity of the polymer backbone and the stability of the helical conformation. The copolymerization using the achiral comonomers having linear or α-branched alkyl groups showed poor or no cooperative effects on the helical conformation, meaning that these polymers exist in a disordered state. On the other hand, a stable helical conformation, i.e., a long persistence length of the helical domain, was attainable for the polymer having β-branched alkyl chains (poly(1e), R = i-C4H9), which was evidenced by a clear, positive nonlinear relationship between the feed ratio of 1e to 2 and the optical rotation of the copolymers. UV-visible spectroscopic studies demonstrated that, in CHCl3, the helical and disordered main chains display absorption centered at 400 and 320 nm, respectively, which resulted in different colors in solution of the helical (yellow) and disordered (achromic) polymers. Thermochromism was achieved by the thermally induced reversible conformational change between helical and disordered states. The thermodynamic parameters (ΔGr; ΔHr, and ΔSr) that govern the stability of the helical conformation of a copolymer were estimated by the temperature dependence of the populations of the helical and disordered states using UV - visible spectra.
Highly selective and sensitive fluorescence turn-on probe for a catalytic amount of Cu(I) ions in water through the click reaction
Park, Seokan,Kim, Hae-Jo
, p. 4473 - 4475 (2012)
A simple azide-functionalized coumarin (1) was utilized as a fluorescence turn-on probe for a catalytic amount of Cu(I) ions in HEPES buffer. The probe has shown a selective and sensitive response to the cuprous ions over other various cations through a Cu(I)-mediated click reaction of 1 to an alkyne. When a catalytic amount of copper sulfates was added in the presence of ascorbate, the prominent fluorescence 'Off-On' change of 1 was observed so that submicromolar concentration of copper ions was detectable by the naked eye.
Structural and Activity Relationships of 6-Sulfonyl-8-Nitrobenzothiazinones as Antitubercular Agents
Chiarelli, Laurent R.,Fan, Dongguang,Han, Quanquan,Lu, Yu,Qiao, Chunhua,Shi, Rui,Stelitano, Giovanni,Wang, Bin,Huszár, Stanislav,Miku?ová, Katarína,Savková, Karin
supporting information, p. 14526 - 14539 (2021/10/26)
The benzothiazinone (BTZ) scaffold compound PBTZ169 kills Mycobacterium tuberculosis by inhibiting the essential flavoenzyme DprE1, consequently blocking the synthesis of the cell wall component arabinans. While extraordinarily potent against M. tuberculosis with a minimum inhibitory concentration (MIC) less than 0.2 ng/mL, its low aqueous solubility and bioavailability issues need to be addressed. Here, we designed and synthesized a series of 6-methanesulfonyl substituted BTZ analogues; further exploration introduced five-member aromatic heterocycles as linkers to attach an aryl group as the side chain. Our work led to the discovery of a number of BTZ derived compounds with potent antitubercular activity. The optimized compounds 6 and 38 exhibited MIC 47 and 30 nM, respectively. Compared to PBTZ169, both compounds displayed increased aqueous solubility and higher stability in human liver microsomes. This study suggested that an alternative side-chain modification strategy could be implemented to improve the druglike properties of the BTZ-based compounds.
Efficient and Recyclable Cobalt(II)/Ionic Liquid Catalytic System for CO2 Conversion to Prepare 2-Oxazolinones at Atmospheric Pressure
Zhou, Zhi-Hua,Chen, Kai-Hong,He, Liang-Nian
supporting information, p. 1223 - 1228 (2019/11/21)
Converting CO2 into value-added chemicals represents a promising way to alleviate the CO2 derived environmental issues, for which the development of catalysts with high efficiency and recyclability is very desirable. Herein, the catalytic system by combining cobalt source and ionic liquid (IL) has been developed as the efficacious and recyclable catalyst for the carboxylative cyclization of propargylic amine and CO2 to prepare 2-oxazolinones. In this protocol, various propargylic amines were successfully transformed into the corresponding 2-oxazolinones with CoBr2 and diethylimidazolium acetate ([EEIM][OAc]) as the catalyst under atmospheric CO2 pressure. It is worth noting that the turnover number (TON) of this transformation can be up to 1740, presumably being attributed to the cooperative effect of the cobalt and IL. Furthermore, the existence of IL enables the catalytic system to be easily recycled to 10 times without losing its activity.
