The correlation between the surface-active characteristics of SAFOL 23 – alcohol – water systems and the length of the alkyl radical of the alcohol

The effect of isobutyl and isoamyl alcohols on the surface-active characteristics of SAFOL 23 nonionic sur-factant was studied. The surface tension isotherms (STI) of an aqueous solution of surfactant and its water-alcohol compositions are obtained. The structure of mixed micelles and the values of the surfactant interac-tion factor in the micelle, based on the STIs of SAFOL 23 – alcohol – water systems, were calculated. The dependence of surface activity on the SAFOL 23: alcohol ratio passes through a maximum, which is associat-ed with the transition of alcohol from co-surfactant to co-solvent due to the increase in its quantity. The wet-ting process of high dispersed polytetrafluoroethylene (PTFE) by SAFOL 23 – alcohol – water compositions was studied, contact angle isotherms were constructed. The PTFE surface was hydrophilized by compositions at ratios which comply with surface activity maximum. SAFOL 23 is more adsorbed on the surface of the sol-id phase than on the liquid-gas interface. The appending of alcohol into an aqueous solution of surfactant changes the ratio between hydrophilic and lipophilic groups of the composition, which affects cloud point. It significantly expands the range of application of surfactants and allows the use of SAFOL 23 as a solubilizer, emulsifier and wetting agent.

Exploring the Anti-Cancer Mechanism of Novel 3,4′-Substituted Diaryl Guanidinium Derivatives

We previously identified a guanidinium-based lead compound that inhibited BRAF through a hypothetic type-III allosteric mechanism. Considering the pharmacophore identified in this lead compound (i.e., “lipophilic group”, “di-substituted guanidine”, “phenylguanidine polar end”), several modifications were investigated to improve its cytotoxicity in different cancer cell lines. Thus, several lipophilic groups were explored, the di-substituted guanidine was replaced by a secondary amine and the phenyl ring in the polar end was substituted by a pyridine. In a structure-based design approach, four representative derivatives were docked into an in-house model of an active triphosphate-containing BRAF protein, and the interactions established were analysed. Based on these computational studies, a variety of derivatives was synthesized, and their predicted drug-like properties calculated. Next, the effect on cell viability of these compounds was assessed in cell line models of promyelocytic leukaemia and breast, cervical and colorectal carcinomas. The potential of a selection of these compounds as apoptotic agents was assessed by screening in the promyelocytic leukaemia cell line HL-60. The toxicity against non-tumorigenic epithelial MCF10A cells was also investigated. These studies allowed for several structure-activity relationships to be derived. Investigations on the mechanism of action of representative compounds suggest a divergent effect on inhibition of the MAPK/ERK signalling pathway.

Inhibition of Tyrosyl-DNA Phosphodiesterase 1 by Lipophilic Pyrimidine Nucleosides

Inhibition of DNA repair enzymes tyrosyl-DNA phosphodiesterase 1 and poly(ADP-ribose)polymerases 1 and 2 in the presence of pyrimidine nucleoside derivatives was studied here. New effective Tdp1 inhibitors were found in a series of nucleoside derivatives possessing 2′,3′,5′-tri-O-benzoyl-d-ribofuranose and 5-substituted uracil moieties and have half-maximal inhibitory concentrations (IC50) in the lower micromolar and submicromolar range. 2′,3′,5′-Tri-O-benzoyl-5-iodouridine manifested the strongest inhibitory effect on Tdp1 (IC50 = 0.6 μM). A decrease in the number of benzoic acid residues led to a marked decline in the inhibitory activity, and pyrimidine nucleosides lacking lipophilic groups (uridine, 5-fluorouridine, 5-chlorouridine, 5-bromouridine, 5-iodouridine, and ribothymidine) did not cause noticeable inhibition of Tdp1 (IC50 > 50 μM). No PARP1/2 inhibitors were found among the studied compounds (residual activity in the presence of 1 mM substances was 50–100%). Several O-benzoylated uridine and cytidine derivatives strengthened the action of topotecan on HeLa cervical cancer cells.

Progresses in Synthesis of Polycarboxylate Superplasticizer

The prerequisite to synthesize PCE was to prepare new macromonomers with controlled molecular mass, adjustable hydrophilic-lipophilic groups, long-chain alkyl groups, and large terminal hydroxyl groups as well. Structural modifications in the molecular scale of polycarboxylate superplasticizer (PCE) would lead to changes in properties of dispersion and water retention as well as enhancement in the compatibility of Portland cement and so on. This paper reviewed recent developments from synthetic methods of macromonomers as the initial step of production of PCE, PCE at room and elevated temperatures, and relationships between structure and properties of PCE. Through the analysis of references, it was found that PCE synthesized at room temperature had the same performance with PCE synthesized at elevated temperature in terms of conversion rate and initial dispersion in cement but broader molecular weight distribution. Conclusively, the dispersion of PCE in cement might be explained by multiple theories rather than a single one based on development trends as discussed in this paper.

Synthesis and characterization of novel 7-oxy-3-ethyl-6-hexyl-4-methylcoumarin substituted metallo phthalocyanines and investigation of their photophysical and photochemical properties

Coumarin functionalized metallo phthalocyanines shows increased singlet oxygen quantum yields when included lipophilic groups.

Design, synthesis and characterization of bitumen emulsifiers based on molecular simulation

Under the guidance of molecular simulation technology, the Monte Carlo molecular mechanics simulation was used to calculate the compatibility of different lipophilic groups with each component of bitumen, and the compatibility of different hydrophilic groups with water. Based on the calculated results of interaction parameters Chi and mixture energy Emix, the preferred structures of lipophilic and hydrophilic groups of bitumen emulsifier were determined. The target bitumen emulsifier was then synthesized by the reaction of organic acid and polyamine. The molecular simulation results showed that the compatibility of lipophilic group T11 with the bitumen was the best, and the mixing ability of the hydrophilic group H5 with water was excellent. The experimental results show that the preferred structures T11H5 had a good emulsifying performance to prepare emulsified bitumen with good storage stability, consistent with the results of the molecular simulation.