Hydroxylamine-mediated C–C amination via an aza-hock rearrangement

Despite the widespread use of anilines, synthetic challenges to these targets still exist. Selectivity is often an issue, when using the traditional nitration-reduction sequence or more modern approaches, including arene C–H aminations catalyzed by transition metals, photosensitizers, or electrodes. Accordingly, there is still a need for general methods to rapidly, directly access specific isomers of substituted anilines. Here, we report a simple route towards the synthesis of such motifs starting from benzyl alcohols, which are converted to anilines by the use of arylsulfonyl hydroxylamines, via an aza-Hock rearrangement. Good to excellent yields are observed. The method is applicable to various benzyl alcohol surrogates (such as ethers, esters, and halides) as well as simple alkylarenes. Functionalizations of pharmaceutically relevant structures are feasible under the reaction conditions. Over ten amination reagents can be used, which facilitates the rapid assembly of a vast set of compounds.

SMALL BLADE TECHNOLOGY IN THE EARLY UPPER PALEOLITHIC INDUSTRIES FROM DENISOVA CAVE: DATA FROM ANALYSIS OF A LITHIC REDUCTION SEQUENCE

The paper discusses the results from an analysis of five cores associated with Layer 11 in the Southern Chamber of Denisova Cave, intended to obtain small elongated blanks such as bladelets and small blades. Analysis of a lithic reduction sequence employed in the research has made it possible to clearly recognize the phases in producing flake scars on lithic artifacts through the preparation of core blanks, and in core reduction, as well as to determine stages at which some of these pieces were used as tools. The analysis provided insights into a general flaking pattern for the cores under study. Such artifacts were predominantly made on large massive flake blanks, had a plain striking platform, and the working edge showing traces of reduction associated with detaching the target flakes. These technological characteristics are fully consistent with the technological repertoire of a hominin group, based on cores from the same assemblage, intended to obtain larger target removals such as flakes and blades. A cross section of the flaking surface shows no evidence for a deliberately created and maintained convex relief, while typologically four of the five artifacts were defined as sub-prismatic. The analysis of a lithic reduction sequence shows that artifacts from the examined collection related to the production of blanks in the form of small flake-blades, without using new techniques and the controlled reduction of a flaking surface.

Methods of biological treatment intensification aimed at removal of heavy metals

Introduction. The application of microorganisms, capable of using chemical elements with variable valency as terminal electron acceptors, in the wastewater treatment technology can improve the ecological and energy efficiency of biological treatment plants. Materials and methods. The co-authors employed the analytical generalization of findings, including the overview of literary sources, laboratory researches involving standard and advanced methodologies and analytical equipment. Results. Cr(6+) Мn(4+), highly concentrated in wastewaters of versatile production facilities, deserve attention as terminal electron acceptors. The ability of Асіnеtobacter, a non-adapted aerobic bacteria, to reduce Мn(4+), Сr(6+) in the culture medium under a layer of vasseline oil, was studied in the laboratory environment. In the course of the laboratory research, different aspects of Сr(6+)- и Мn(4+) reduction were studied, namely, the bacteria’s chromate reduction ability, as Сr(6+) concentration change curves were obtained for the process of reduction; the influence of Сr(6+) and Мn(2+) reductions on processes of chromate and manganese reduction was identified; water treatment efficiency boosted by Сr(6+) was identified; changes in the reduction sequence in case of their co-presence in the culture medium were checked; the sequence of Сr(6+) and Мn(4+) reduction in case of their co-cultivation together with the bacteria was identified, as well. A succession of experiments with Pseudomonas bacteria was held to validate the results. Conclusions. The experiments have proven that aerobic bacteria, including Асіnеtobacter, P. aeruginosa P-1, P. flurescens var. Pseudo-iodinum P-11, P. Mendocina P-13, P. stutzeri P-19, can develop anaerobic respiration ability under certain conditions. The co-authors have identified that Сr(6+)- and Мn(4+) reduction is applicable by microorganisms, belonging to varied taxonomic groups, in anaerobic cultivation environments, if Сr(6+)- and Мn(4+) act as terminal acceptors of electrons; the co-authors have also reconstructed the reduction sequence: denitrifying bacteria use МnО2 much more efficiently than Сr(6+). Microbial chromate reduction precedes Мn(4+) reduction, while products of their metabolism are less toxic. Acknowledgements. The co-authors would like to express gratitude to the executives of the St. Petersburg University of Architecture and Civil Engineering for the research grant and to all reviewers and the editorial team for the publication of this material.

Multigram-scale flow synthesis of the chiral key intermediate of (−)-paroxetine enabled by solvent-free heterogeneous organocatalysis

The continuous flow synthesis of the chiral key intermediate of (−)-paroxetine is demonstrated via a solvent-free organocatalytic conjugate addition followed by a telescoped reductive amination–lactamization–amide/ester reduction sequence.

LAPIDARY CRAFT PRODUCTION AT 17:S3E1 AND 18:S3E1, THE TLAJINGA DISTRICT, TEOTIHUACAN

A total of 84 two-liter soil samples from Proyecto Arqueológico Tlajinga Teotihuacan (PATT) sites 17:S3E1, 18:S3E1, and the Street of the Dead excavations were fine-screened through 1-mm mesh and were sorted to retrieve tiny artifacts. The raw lapidary stone and marine shell material was then analyzed to assess the presence and intensity of artifact production. These data were also compared with the lapidary material of nearby 33:S3W1. A robust multicraft lapidary production was revealed. Sequins and stemmed trapezoid pendants were manufactured from slate, greenstone, marine shell, and mica, with slate being the predominant raw material being worked. A reduction sequence for slate sequins was developed based on the various shapes of slate materials that indicated the stages of production. Importantly, this lapidary craft production was not recognized from surface collections prior to excavation.

Identification of Bifacial Components in Middle Paleolithic Techno-Complexes (Based on the Chagyrskaya Cave Assemblages)

Previously, occasional bifacial tools found in different industrial variants of the Altai Middle Paleolithic were not considered as cultural markers that could be used to differentiate the technological/cultural variants. They rather were a bright but situational manifestation of the typological variability, especially in the case of the Sibiryachikha assemblages. Purpose. The article discusses various research approaches used to determine and evaluate the bifacial component in the Middle Paleolithic lithic assemblages, namely attributive analysis with a set of specific attributes, scar-pattern analysis and experimental modelling. Results. As a result of recent studies at the site Chagyrskaya Cave, the key-site of Sibiryachikha, we found out that all the bifaces were made using plano-convex technology. In the Chagyrskaya Cave assemblage all stages of bifacial production have been noticed? including pre-forms, bifacial tools and tools made on bifacial thinning flakes, accompanied by numerous bifacial thinning flakes and bifacial thinning chips. Re-investigation of the Okladnikov assemblage should bring a new, previously unknown series of technical spalls related to the bifacial plano-convex technology. A similar situation is with Karabom complexes, where all bifacial tools are made using bi-convex bifacial technology. Thus, criteria for technological distinction of bifacial production are of special importance. Conclusion. Our experiments have shown that the proportion of chips associated with bifacial production is much higher than it can be determined while analyzing archaeological assemblages. Taking in account the new data on bifacial technologies in the region, we conclude that variability of Middle Paleolithic complexes has become more complex. To evaluate the bifacial component in Paleolithic assemblages, all stages of bifacial flaking should be documented, including bifacial pre-forms, technical spalls related to bifacial reduction sequence, chips, blanks which demonstrate bifacial flaking errors and tools made on bifacial thinning flakes and bifacial tools. A complete set of bifacial production is present at the Chagyrskaya Cave assemblage due to the fact that the cave was constantly visited and had a sufficiently long habitation cycle as a source of raw materials. In the assemblage, a complete sequence of lithic raw material exploitation was processed. Taking into account the fact that Chagyrskaya Cave and Okladnikov Cave are associated only with Neanderthal remains, it can be assumed that bifacial plano-convex technology in the Middle Paleolithic of Altai is linked to Neanderthal population in the region.