Synthetic Attempts Research Articles

Cultural Evolutionary Psychology as Generalization by Recursion

AbstractCultural evolutionary psychology (CEP) accounts for the cultural evolution of cognition. It is based on evolutionary psychology and cultural evolutionary theory and aims at a synthetic attempt which is achieved by what we want to call ‘generalization by recursion’. We argue in this paper that the evolutionary psychology program as a whole could greatly benefit from CEP’s generalization. As we will show, there is one theoretical element in particular, that CEP relevantly generalizes in contrast to its predecessors. It comes from cultural evolutionary theory and has been referred to as the ‘dual inheritance argument’. CEP’s novelty consists in showing that not only cognitive products (‘grist’) but also cognitive mechanisms (‘mills’) are subject to cultural evolution and provides lots of empirical evidence for this claim. This account is ‘recursive’, because CEP’s generalization of the dual inheritance argument theoretically employs a recursive feedback-loop between cultural learning and cultural evolution. We also argue that this account might be considered to supersede unificatory and reductionistic efforts of its competitors, because it is stronger than purely structural or analogical unification while at the same time it is not too strong in order to fall prey to implausible reductionism.

Nominal CaAl2Pt2 and Ca2Al3Pt – two new Intermetallic Compounds in the Ternary System Ca−Al−Pt

AbstractSingle crystals of CaAl2Pt2, Ca2Al3Pt and Ca2AlPt2 were initially observed in an attempt to synthesize Ca3Al4Pt4. Their structures were determined using single‐crystal X‐ray diffraction experiments. While nominal CaAl2Pt2 (CaBe2Ge2 type, P4/nmm, a=426.79(2), c=988.79(6) pm, wR2=0.0679, 246 F2 values and 18 variables) and Ca2Al3Pt (Mg2Cu3Si type, P63/mmc, a=561.46(5), c=876.94(8) pm, wR2=0.0664, 214 F2 values and 13 variables) exhibit Al/Pt mixing, for Ca2AlPt2 (Ca2Ir2Si type, C2/c, a=981.03(2) b=573.74(1), c=772.95(2) pm, β=101.862(1)° wR2=0.0307, 2246 F2 values and 25 variables) no mixing was observed. Subsequently, the nominal compositions were targeted with synthetic attempts from the elements using arc‐melting and annealing techniques. For CaAl2Pt2 and Ca2Al3Pt always multi‐phase mixtures were observed while Ca2AlPt2 could be obtained as almost X‐ray pure material. Quantum‐chemical calculations were used to investigate the charge transfer in these compounds rendering them polar intermetallics with a designated [AlxPty]δ− polyanion and Caδ+ cations in the cavities of the polyanions.

Structural Elucidation of a New Puzzling Compound Emerged from Doebner Quinoline Synthesis

The quinoline ring is found in many biologically active natural alkaloids and is still being highly exploited by researchers due to its numerous potential applications in fields ranging from pharmacology to material science. During our synthetic attempts for new quinoline-4-carboxylic acids, using an extended version of the Doebner reaction, a new puzzling compound emerged when para-iodine aniline was reacted with salicylaldehyde and pyruvic acid in acetic acid as a reaction medium. The chemical structure of this new compound was established based on the information obtained from 1D and 2D NMR experiments (1H-, 13C-, and 15N-NMR), corroborated with MS spectrometry and IR spectroscopy. The photophysical properties (UV–vis and fluorescence) were also investigated. The proposed structure contains as the main elements a 1,4-dioxane-2,5-dione core symmetrically substituted with a propylidene chain that has attached to it a salicylaldehyde fragment and a pyrrole-2-one ring containing two 4-iodophenyl fragments. The isolation of this compound, reported here for the first time, is direct evidence that unexpected compounds can emerge from “classical” synthetic pathways when the right components are combined.

Fusion of Cyclohepta[def]fluorene Units: Toward Synthesis of High‐Spin Non‐Benzenoid Nanographenes

AbstractNon‐benzenoid diradicaloids possessing high‐spin ground states are attractive synthetic targets given their high potential for spintronics and quantum computing. Nevertheless, the synthesis of such compounds remains highly challenging due to their inherent instability. In this work, we present the synthetic attempt towards creating a non‐benzenoid diradicaloid (1) with a triplet ground state by fusing two cyclohepta[def]fluorene units onto a benzene ring. Our synthetic approach involves both oxidation and reduction pathways. In the oxidation path, we obtained the partially dehydrogenated products 1+H and 1+2H containing an indeno[1,2‐b]fluorene core from the tetrahydro precursor (2). However, further dehydrogenation to afford the target molecule (1) did not proceed. On the other hand, with the reduction pathway, a novel tetraketone precursor (9) with two pairs of pentagons and heptagons was successfully synthesized. The subsequent nucleophilic attack however was proved to be difficult probably due to the unselective nucleophilic addition on the zigzag nanographene ketones. Furthermore, UV‐vis absorption, cyclic voltammetry, and theoretical calculations were conducted to explore the optical, electrochemical properties, and aromaticity of all the obtained molecules (1+H, 1+2H and 9). Although the desired target 1 is not achieved, our work provides insight into designing novel high‐spin non‐benzenoid NGs based on nonalternant cyclohepta[def]fluorene system.

Synthetic account on indoles and their analogues as potential anti-plasmodial agents.

Malaria caused by P. falciparum, has been recognized as one of the major infectious diseases causing the death of several patients as per the reports from the World Health Organization. In search of effective therapeutic agents against malaria, several research groups have started working on the design and development of novel heterocycles as anti-malarial agents. Heterocycles have been recognized as the pharmacophoric features for the different types of medicinally important activities. Among all these heterocycles, nitrogen containing aza-heterocycles should not be underestimated owing to their wide therapeutic window. Amongst the aza-heterocycles, indoles and fused indoles such as marinoquinolines, isocryptolepines and their regioisomers, manzamines, neocryptolenines, and indolones have been recognized as anti-malarial agents active against P. falciparum. The present work unleashes the synthetic attempts of anti-malarial indoles and fused indoles through cyclocondensation, Fischer-indole synthesis, etc. along with the brief discussions on structure-activity relationships, in vitro or in vivo studies for the broader interest of these medicinal chemists, working on their design and development as potential anti-malarial agents.

Stable π-Extended Thio[7]helicene-Based Diradical with Predominant Through-Space Spin-Spin Coupling.

In this work, a novel π-extended thio[7]helicene scaffold was synthesized, where the α-position of the thiophene unit could be functionalized with bulky phenoxy radicals after considerable synthetic attempts. This open-shell helical diradical, ET7H-R, possesses high stability in the air, nontrivial π conjugation, persistent chirality, and a high diradical character (y0 of 0.998). The key feature is a predominant through-space spin-spin coupling (TSC) between two radicals at the helical terminals. Variable-temperature continuous-wave electron spin resonance (cw-ESR) and superconducting quantum interference device (SQUID) magnetometry in the solid state reveal a singlet ground state with a nearly degenerate triplet state of ET7H-R. These results highlight the significance of a stable helical diradicaloid as a promising platform for investigating intramolecular TSCs.

Development of comprehensive approaches to characterizing CuII complexes: structures in solution and solid‐state, dynamic behavior, and bioactivity

AbstractCuII ternary systems with aromatic N‐donors (1,10‐phenanthroline, dipyrido‐[3,2‐f:2’,3’‐h]‐quinoxaline, and 2‐methyldipyrido‐[3,2‐f:2’,3’‐h]‐quinoxaline) and amino acids have been extensively studied in water solution under closely physiological conditions using several techniques, including potentiometric pH titration, mathematical modeling, nuclear magnetic relaxation, EPR, and DFT calculations. Based on the distribution diagrams of the complex species, single crystal syntheses of the ternary systems CuII‐aromatic N‐donor‐L‐amino acid were carried out. As a result, several crystal structures of the complexes with the desired copper‐to‐ligand ratio were established by X‐ray diffraction analysis. The most successful synthetic attempts were with L‐proline and L‐serine, resulting in the crystals with the desired copper(II) to ligand ratio. The developed approach made it possible to thoroughly describe systems with major proteinogenic amino acids in the L‐configuration. Numerous non‐covalent interactions such as H‐bonds, π‐π stacking, d‐π interactions, lone electron pair‐π interactions between CuII atom, conjugated aromatic ligand system, counterions, and water molecules were found to affect the stability and structure of the resulting complex particles. It has been found that in the CuII–N‐donor–amino acid systems there is an acceleration of ligand exchange by a factor of 2–25 compared to CuII‐amino acid systems, which is explained by taking into account steric effects, d‐π interactions, and the pseudo Jahn‐Teller effect. The investigated systems were tested for antitumor activity against MCF‐7, PC‐3, OVCAR‐4, SNB‐19, and M‐14 cell lines, and most samples, in particular, CuII–Phen–L‐His, CuII–MeDPQ−L‐Val and CuII–MeDPQ−L‐Ser, showed a therapeutic activity index greater than 2 for all selected cell types, which opens up prospects for their medical application.

EM Database v1.0: A benchmark informatics platform for data-driven discovery of energetic materials

Large-scale data demonstrates great significance for the discovery of novel energetic materials (EMs). However, the open-source databases of EMs are not readily available. In pursuit of high-performance EMs before synthetic attempts in the laboratory, the theoretically predicted properties and experimental results that can be easily accessed are desired. Herein, a benchmark informatics platform of EMs, namely EM Database, has been developed for the purpose of data storage and sharing. EM Database v1.0 currently contains the properties of approximately 100000 unique compounds obtained through quantum chemistry (QC) calculations and the experimental results of about 10000 unique compounds extracted from literature. The QC data in the database were extracted via ground-state density functional calculations using the B3LYP/6-31G(d,p) method. These data include geometrical conformation, electronic structures, and predicted properties (i.e., crystal density, enthalpy of sublimation, molar heat of formation, detonation pressure, detonation velocity, detonation heat, and detonation volume) obtained using models of quantitative structure-property relationships. The experimental data were manually collected from literature and were then doubly curated by our project team members. These data include the physicochemical, thermal, combustion, detonation, spectra, and sensitivity properties. In this paper, we also discuss the techniques for constructing the EM Database and present the fundamental features of the database. The EM Database is expected to serve as an effective benchmark informatics platform for forthcoming research on EMs.

Homomeric chains of intermolecular bonds scaffold octahedral germanium perovskites.

Perovskites with low ionic radiimetal centres (for example, Ge perovskites) experience both geometrical constraints and a gain in electronic energy through distortion; for these reasons, synthetic attempts do not lead to octahedral [GeI6] perovskites, but rather, these crystallize into polar non-perovskite structures1-6. Here, inspired by the principles of supramolecular synthons7,8, we report the assembly of an organic scaffold within perovskite structures with the goal of influencing the geometric arrangement and electronic configuration of the crystal, resulting in the suppression of the lone pair expression of Ge and templating the symmetric octahedra. We find that, to produce extended homomeric non-covalent bonding, the organic motif needs to possess self-complementary properties implemented using distinct donor and acceptor sites. Compared with the non-perovskite structure, the resulting [GeI6]4- octahedra exhibit a direct bandgap with significant redshift (more than 0.5 eV, measured experimentally), 10times lower octahedral distortion (inferred from measured single-crystal X-ray diffraction data) and 10times higher electron and hole mobility (estimatedby density functional theory). We show that the principle of this design is not limited to two-dimensional Ge perovskites; we implement it in the case of copper perovskite (also a low-radius metal centre), and we extend it to quasi-two-dimensional systems. We report photodiodes with Ge perovskites that outperform their non-octahedral and lead analogues. The construction of secondary sublattices that interlock with an inorganic framework within a crystal offers a new synthetic tool for templating hybrid lattices with controlled distortion and orbital arrangement, overcoming limitations in conventional perovskites.

Propargyl Alcohols as Bifunctional Reagents for Divergent Annulations of Biphenylamines via Dual C-H Functionalization/Dual Oxidative Cyclization.

The C-H functionalization strategy provides access to valuable molecules that previously required convoluted synthetic attempts. Dual C-H unsymmetrical functionalization, with a single bifunctional reagent, is an effective tactic. Propargyl alcohols (PAs), despite containing a reactive C≡C bond, have not been explored as building blocks via oxidative cleavage. Annulations via C-H activation are a versatile and synthetically attractive strategy. We disclose PA as a new bifunctional reagent for unsymmetrical dual C-H functionalization of biphenylamine for regioselectively annulated outcomes. On tuning the conditions, the annulation bifurcated towards an unusual dual oxidative cyclization. This method accommodates a wide range of PAs and showcases late-stage diversification of some natural products.

Propargyl Alcohols as Bifunctional Reagents for Divergent Annulations of Biphenylamines via Dual C−H Functionalization/Dual Oxidative Cyclization

AbstractThe C−H functionalization strategy provides access to valuable molecules that previously required convoluted synthetic attempts. Dual C−H unsymmetrical functionalization, with a single bifunctional reagent, is an effective tactic. Propargyl alcohols (PAs), despite containing a reactive C≡C bond, have not been explored as building blocks via oxidative cleavage. Annulations via C−H activation are a versatile and synthetically attractive strategy. We disclose PA as a new bifunctional reagent for unsymmetrical dual C−H functionalization of biphenylamine for regioselectively annulated outcomes. On tuning the conditions, the annulation bifurcated towards an unusual dual oxidative cyclization. This method accommodates a wide range of PAs and showcases late‐stage diversification of some natural products.

Base-stabilized Neutral Oxoborane and Thioxoborane Supported by a Bis(oxazolinyl)(phenyl)methanide Ligand.

Base-stabilized neutral oxoborane and thioxoborane supported by a bis(oxazolinyl)(phenyl)methanide ligand have been synthesized and structurally characterized. While previous synthetic attempts of oxoborane ligated by β-diketiminate (NacNac) did not allow for its isolation in acid-free form, oxoborane supported by a bis(oxazolinyl)(phenyl)methanide ligand is isolable, due to the absence of imine ɑ-protons and steric protection of enamine carbon. Crystallographic analysis revealed the presence of a B-O double bond close to the shortest end of the reported lengths. Its reactivity has also been examined, and it was majorly governed by the nucleophilicity and basicity of the oxygen atom. The chemical inertness and synthetic convenience of the bis(oxazolinyl)(phenyl)methanide scaffold presented in this work suggest its utility as an innocent alternative to the NacNac scaffold.

Review of Introduction to Cognitive Pragmatics

This article reviews the book—Introduction to Cognitive Pragmatics written by Klaus-Uwe Panther. The book is a synthetic attempt to blend a cognitive linguistic approach to language in use from contemporary pragmatics. Although a few works on this reconciled filed have been published in the past 30 years, the term Cognitive Pragmatics is not well established in linguistic community yet (Schimid, 2012). In this vein, this newly published book makes a few steps forward on the road to an interface study approach both on cognitive linguistics and pragmatics. This review introduces and analyzes the main content of the book as well as providing a critical comment.

Synthetic attempts toward α‐tocopherol—An overview

AbstractThe discovery of vitamin E as an essential factor in the diet was a scientific revolution that enlightened the entire world. Vitamin E was discovered in the year 1922 by Herbert M. Evans and K. Scott Bishop and the first synthetic attempt toward α‐tocopherol appeared almost two decades later through a condensation reaction. During the second world war, similar Lewis acid‐catalyzed condensation approaches were accomplished starring 1,3,5‐trimethyl hydroquinone and varying the other component. The stereochemistry of the three chiral centers present in the α‐tocopherol molecule was revealed in the early 1960s and thereafter scientific community took interest in synthesizing natural (2R,4′R,8′R)‐α‐tocopherol molecule with high enantioselectivity. During the first decade of the 21st century, several groups have applied Brønsted and Lewis acid catalysts to mobilize the condensation reactions toward α‐tocopherol. In the year 2012, we celebrated 100 years of vitamins and now we are celebrating the 100th anniversary of vitamin E discovery. This historical review highlights key research achievements since the last century and untold stories on α‐tocopherol and/or vitamin E.

Konstytucja marcowa – konstytucja paradoksów

The March constitution – a constitution of paradoxes This article presents a synthetic attempt to address the role that the March Constitution of 1921 has played in the development of the Polish constitutional thought. It discusses the achievements and the weaknesses of the March Constitution. On the one hand, its significant advantages included recognising a catalogue of fundamental rights, guaranteeing independence of the judiciary, introducing judicial control of administrative acts and state liability for breaches of law. On the other hand, its weaknesses lay in the lack of solutions to stabilise the position of the government, a broad and imprecisely defined status of decree laws, and the lack of constitutionality review of laws. The modern and democratic solutions of the March Constitution exceeded the level of advancement of the political and legal culture in the society, which led to abuse and distortion of its constitutional mechanisms, and to an inability to secure the rule of law.

Synthetic Attempts Towards Eminent Anti-viral Candidates of SARS-CoV.

Severe Acute Respiratory Syndrome (SARS) aka SARS-CoV spread over southern China for the first time in 2002-2003 and history repeated again since last year and took away lives of more than two million people so far. On March 11, 2020 COVID-19 outbreak was officially declared as pandemic by World Health Organization (WHO). The entire world united to fight back against this ultimate destruction. Around 90 vaccines are featured against SARS-CoV-2 and more than 300 active clinical trials are underway by several groups and individuals. So far, no drugs have been currently approved that can completely eliminate the deadly coronavirus. The promising SARS-CoV-2 antiviral drugs are favipiravir, remdesivir, lopinavir, ribavirin and avifavir. In this review, we have discussed the synthetic approaches elaborately made so far by different groups and chemical companies all around the world towards top three convincing anti-viral drugs against SARS-CoV-2, which are favipiravir, remdesivir and lopinavir.

Preparative-scale synthesis of nonacene

During the last years we have witnessed progressive evolution of preparation of acenes with length up to dodecacene by on-surface synthesis in ultra-high vacuum or generation of acenes up to decacene in solid matrices at low temperatures. While these protocols with very specific conditions produce the acenes in amount of few molecules, the strategies leading to the acenes in large quantities dawdle behind. Only recently and after 70 years of synthetic attempts, heptacene has been prepared in bulk phase. However, the preparative scale synthesis of higher homologues still remains a formidable challenge. Here we report the preparation and characterisation of nonacene and show its excellent thermal and in-time stability.

Biological Activities of Schiff Bases Incorporating Benzothiazole Moiety

The functionalization of organic molecules with the Schiff bases having benzothiazole moiety has grown rapidly due to its multiple therapeutic and pharmacological properties. They have driven enormous studies on their stereochemistry, bioactivity and synthetic attempts. The benzothiazole moiety is infinitesimal but broadly used for industrial purposes and also exhibits a broad range of biological activities. Study carried out on Schiff bases having benzothiazole had well-known promising activities like antimicrobial, antimalarial, antifungal, antitubercular, antiviral, antitumor, analgesic, anti-inflammatory and many more. This review brings forward a systematic and comprehensive survey of the reactivity and biological properties associated with the Schiff bases-benzothiazole derivatives and their analogs.

Molecular set transformer: attending to the co-crystals in the Cambridge structural database

Molecular set transformer is a deep learning architecture for scoring molecular pairs found in co-crystals, whilst tackling the class imbalance problem observed on datasets that include only successful synthetic attempts.

E3 Ligase Ligands in Successful PROTACs: An Overview of Syntheses and Linker Attachment Points.

Proteolysis-targeting chimeras (PROTACs) have received tremendous attention as a new and exciting class of therapeutic agents that promise to significantly impact drug discovery. These bifunctional molecules consist of a target binding unit, a linker, and an E3 ligase binding moiety. The chemically-induced formation of ternary complexes leads to ubiquitination and proteasomal degradation of target proteins. Among the plethora of E3 ligases, only a few have been utilized for the novel PROTAC technology. However, extensive knowledge on the preparation of E3 ligands and their utilization for PROTACs has already been acquired. This review provides an in-depth analysis of synthetic entries to functionalized ligands for the most relevant E3 ligase ligands, i.e. CRBN, VHL, IAP, and MDM2. Less commonly used E3 ligase and their ligands are also presented. We compare different preparative routes to E3 ligands with respect to feasibility and productivity. A particular focus was set on the chemistry of the linker attachment by discussing the synthetic opportunities to connect the E3 ligand at an appropriate exit vector with a linker to assemble the final PROTAC. This comprehensive review includes many facets involved in the synthesis of such complex molecules and is expected to serve as a compendium to support future synthetic attempts towards PROTACs.