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[Display omitted] Reactions between 4-(propargyloxy)benzaldehyde with anthracene-9-carbaldehyde oxime or pyrene-1-carbaldehyde oxime in the presence of chloramine T in ethanol lead to new isoxazole-containing derivatives of benzaldehyde. The subsequent acid-catalyzed condensation of these compounds with 2-methylresorcinol in chloroform/trifluoroacetic acid mixtures affords novel calix[4]resorcinols with anthaceneand pyrene-ended isoxazole-containing fragments as all– cis (rccc) and cis–trans–trans (rctt) diastereoisomers, their ratios being dependent on the CF 3 CO 2 H percentage in the medium. The crystal structures of pyrene-ended isoxazole-containing benzaldehyde and corresponding calix[4]resorcinol rctt isomer have been established by single crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

The absolute configuration and stability of two thianthrene chiral sulfoxides has been determined by means of X-ray single-crystal structure determinations. The analyses and configurations allow verification that the diastereomeric sulfoxides are stable in solution and are not interconverting, which has been suggested in some studies of sulfoxides. The two thianthrene sulfoxides have slightly different Rf values, which allowed their separation using flash chromatography on silica. The spots run back-to-back, which posed a challenge for their separation. The pure, separated compounds in solution remain as separate, single spots on a Thin Layer Chromatography (TLC) plate. [ABSTRACT FROM AUTHOR]

The absolute configuration and stability of two thianthrene chiral sulfoxides has been determined by means of X-ray single-crystal structure determinations. The analyses and configurations allow verification that the diastereomeric sulfoxides are stable in solution and are not interconverting, which has been suggested in some studies of sulfoxides. The two thianthrene sulfoxides have slightly different Rf values, which allowed their separation using flash chromatography on silica. The spots run back-to-back, which posed a challenge for their separation. The pure, separated compounds in solution remain as separate, single spots on a Thin Layer Chromatography (TLC) plate.

The quinoxaline core is a promising scaffold in medicinal chemistry. Multiple quinoxaline derivatives, such as the topoisomerase IIβ inhibitor XK-469 and the tissue transglutaminase 2 inhibitor GK-13, have been evaluated for their antiproliferative activity. Previous work reported that quinoxaline derivatives bearing an oxirane ring present antiproliferative properties against neuroblastoma cell lines SK-N-SH and IMR-32. Likewise, quinoxalines with an arylethynyl group displayed promising antineoplastic properties against glioblastoma and lung cancer cell lines, U87-MG and A549 respectively. Here, 40 new quinoxaline derivatives bearing an oxirane ring were synthesized using a tetrakis(dimethylamino)ethylene (TDAE) strategy and a Sonogashira cross-coupling reaction. Each reaction with TDAE furnished a pair of diastereoisomers cis and trans. These new compounds formed two series according to the substitution of position 2 on the quinoxaline core, with chlorine or phenylacetylene respectively. Each of these isomers was evaluated for antiproliferative activity against neuroblastoma cell lines SK-N-SH and IMR-32 by MTT assay. All cell viability assay results were analyzed using R programming, as well as a statistical comparison between groups of compounds. Our evaluation showed no difference in drug sensitivity between the two neuroblastoma cell lines. Moreover, trans derivatives were observed to display better activities than cis derivatives, leading us to conclude that stereochemistry plays an important role in the antiproliferative activity of these compounds. Further support for this hypothesis is provided by the lack of improvement in antineoplastic activity following the addition of the phenylacetylene moiety, probably due to steric hindrance. As a result, compounds with nitrofuran substituents from the TDAE series demonstrated the highest antiproliferative activity with IC50 = 2.49 ± 1.33 μM and IC50 = 3.96 ± 2.03 μM for compound 11a and IC50 = 5.3 ± 2.12 μM and IC50 = 7.12 ± 1.59 μM for compound 11b against SK-N-SH and IMR-32, respectively. Furthermore, an in silico study was carried out to evaluate the mechanism of action of our lead compounds and predict their pharmacokinetic properties. [ABSTRACT FROM AUTHOR]

The quinoxaline core is a promising scaffold in medicinal chemistry. Multiple quinoxaline derivatives, such as the topoisomerase IIβ inhibitor XK-469 and the tissue transglutaminase 2 inhibitor GK-13, have been evaluated for their antiproliferative activity. Previous work reported that quinoxaline derivatives bearing an oxirane ring present antiproliferative properties against neuroblastoma cell lines SK-N-SH and IMR-32. Likewise, quinoxalines with an arylethynyl group displayed promising antineoplastic properties against glioblastoma and lung cancer cell lines, U87-MG and A549 respectively. Here, 40 new quinoxaline derivatives bearing an oxirane ring were synthesized using a tetrakis(dimethylamino)ethylene (TDAE) strategy and a Sonogashira cross-coupling reaction. Each reaction with TDAE furnished a pair of diastereoisomers cis and trans. These new compounds formed two series according to the substitution of position 2 on the quinoxaline core, with chlorine or phenylacetylene respectively. Each of these isomers was evaluated for antiproliferative activity against neuroblastoma cell lines SK-N-SH and IMR-32 by MTT assay. All cell viability assay results were analyzed using R programming, as well as a statistical comparison between groups of compounds. Our evaluation showed no difference in drug sensitivity between the two neuroblastoma cell lines. Moreover, trans derivatives were observed to display better activities than cis derivatives, leading us to conclude that stereochemistry plays an important role in the antiproliferative activity of these compounds. Further support for this hypothesis is provided by the lack of improvement in antineoplastic activity following the addition of the phenylacetylene moiety, probably due to steric hindrance. As a result, compounds with nitrofuran substituents from the TDAE series demonstrated the highest antiproliferative activity with IC50 = 2.49 ± 1.33 μM and IC50 = 3.96 ± 2.03 μM for compound 11a and IC50 = 5.3 ± 2.12 μM and IC50 = 7.12 ± 1.59 μM for compound 11b against SK-N-SH and IMR-32, respectively. Furthermore, an in silico study was carried out to evaluate the mechanism of action of our lead compounds and predict their pharmacokinetic properties.

[Display omitted] • Design of experiments allows to optimize the diastereoselectivity of the epoxidation. • The α face of the Δ5 steroids has a greater spatial for low-temperature epoxidation. • At room temperature the diastereoselectivity of epoxidation on Δ5 steroids is lost. • qNMR allows to optimize the use of statistical tools such as design of experiments. Diosgenin and its derivatives have proved a huge importance in diverse biological activities. The optimized production of the diastereoisomers of the epoxide of diosgenin acetate by means of mCPBA is reported herein. This transformation had a previous design of experiments using the application of a statistical factorial DoE of 4 parameters (nk), where one variable is varied at a time, while others stay constant. The temperature showed the greatest effect on the reaction yield; so, at 298 K the diastereomeric ratio 3 : 1 of α and β -epoxides, normally found, was raised to 1:1. Time was the second significant variable, but due to its high correlation with temperature, 30 min were required for a global 90% conversion at least. These diastereoisomers were characterized both isolated and in the mixtures obtained, to determine their antioxidant, antimicrobial and antiproliferative activity, finding a low antioxidant capacity by DPPH, but antimicrobial activity at the level of penicillin in gram negative bacteria by 1β better to 1α. The antiproliferative capacity was higher for diastereoisomer β , agreeing with the proportion of the mixture obtained by different conditions, increasing this in relation to the amount of this diastereoisomer present in hormone-dependent cancer cell lines such as Hela, PC-3 and MCF-7, with 10.0 µM obtained values of viability at 21.8 %, 35.8 % and 12.3 % respectively. DoE optimization allows to manipulate the ratio between diastereoisomers with the minimum number of experiments, extending the analysis of the effect of the ratio between diastereoisomers and the in silico potential as well as the biological activity. [ABSTRACT FROM AUTHOR]

South Korea is one of the largest consumers of flame-retardants worldwide. In this study, water, sediment, and biota samples were collected from a highly industrialized lake to investigate contamination, isomeric profiles, source, and the bioaccumulation potential of hexabromocyclododecanes (HBCDDs). Almost all of the sediments were severely contaminated by HBCDDs, which were some of the highest global levels compared to those found in previous studies. The highest concentrations and similar profiles to those of technical mixtures of HBCDDs were observed in creeks passing through industrial complexes, indicating on-going contamination by high consumption of HBCDDs from industrial activities. γ -HBCDD was dominant in water and sediment, whereas α -HBCDD was dominant in fish and shellfish. The diastereoisomeric profiles of HBCDDs in multiple matrices were influenced by proximity to industry and chemical properties. In-situ biota-sediment accumulation factors of α -HBCDDs were > 1 in benthic species, implying that HBCDDs are of great concern in sedimentary environments. • HBCDD isomers were detectable in multiple matrices from an industrialized lake. • Severe HBCDD contamination was identified in creeks near industrialized complexes. • Different diastereoisomeric distributions were observed in multiple matrices. • Diastereoisomeric HBCDD profiles were governed by sources and chemical properties. • In-situ BSAFs of α -HBCDD exceeded 1 for benthic species. [ABSTRACT FROM AUTHOR]