1,268 research outputs found

    An update on the synthesis and reactivity of spiro-fused β-lactams

    Get PDF
    Beta-Lactam ring-containing compounds play a pivotal role in drug design and synthetic chemistry. Spirocyclic beta-lactams, representing an important beta-lactam subclass, have recently attracted considerable interest with respect to new synthetic methodologies and pharmacological applications. The aim of this manuscript is to review the recent progress made in this field, covering publications disseminated between 2011 to 2018 concerning the synthesis and application of spirocyclic beta-lactams. In the first part, new approaches to the synthesis of spirocyclic beta-lactams, including Staudinger synthesis, cyclization and transformation reactions, will be presented. The reactivity and biological properties of spiro-beta-lactams will be described in the second and third part, respectively

    Coupling of 1-alkyl-2-(bromomethyl)aziridines with heteroatom-centered nucleophiles towards 2-[(heteroatom)methyl]aziridines

    Get PDF
    The reactivity of 1-alkyl-2-(bromomethyl)aziridines with respect to different types of oxygen-, nitrogen- and sulphur-centered nucleophiles has been evaluated, pointing to the conclusion that these substrates can be applied successfully as synthetic equivalents for the aziridinylmethyl cation synthon towards the corresponding 2-[(heteroatom)methyl]aziridines in good yields

    Towards a quantum evolutionary scheme: violating Bell's inequalities in language

    Get PDF
    We show the presence of genuine quantum structures in human language. The neo-Darwinian evolutionary scheme is founded on a probability structure that satisfies the Kolmogorovian axioms, and as a consequence cannot incorporate quantum-like evolutionary change. In earlier research we revealed quantum structures in processes taking place in conceptual space. We argue that the presence of quantum structures in language and the earlier detected quantum structures in conceptual change make the neo-Darwinian evolutionary scheme strictly too limited for Evolutionary Epistemology. We sketch how we believe that evolution in a more general way should be implemented in epistemology and conceptual change, but also in biology, and how this view would lead to another relation between both biology and epistemology.Comment: 20 pages, no figures, this version of the paper is equal to the foregoing. The paper has meanwhile been published in another book series than the one tentatively mentioned in the comments given with the foregoing versio

    A Quantum Cognition Analysis of the Ellsberg Paradox

    Full text link
    The 'expected utility hypothesis' is one of the foundations of classical approaches to economics and decision theory and Savage's 'Sure-Thing Principle' is a fundamental element of it. It has been put forward that real-life situations exist, illustrated by the 'Allais' and 'Ellsberg paradoxes', in which the Sure-Thing Principle is violated, and where also the expected utility hypothesis does not hold. We have recently presented strong arguments for the presence of a double layer structure, a 'classical logical' and a 'quantum conceptual', in human thought and that the quantum conceptual mode is responsible of the above violation. We consider in this paper the Ellsberg paradox, perform an experiment with real test subjects on the situation considered by Ellsberg, and use the collected data to elaborate a model for the conceptual landscape surrounding the decision situation of the paradox. We show that it is the conceptual landscape which gives rise to a violation of the Sure-Thing Principle and leads to the paradoxical situation discovered by Ellsberg.Comment: 11 page

    Microwave-assisted regioselective ring opening of non-activated aziridines by lithium aluminium hydride

    Get PDF
    A new synthetic protocol for the LiAlH4-promoted reduction of non-activated aziridines under microwave conditions was developed. Thus, ring opening of 2-(acetoxymethyl)aziridines provided the corresponding beta-amino alcohols, which were then used as eligible substrates in the synthesis of 5-methylmorpholin-2-ones via condensation with glyoxal in THF. The same procedure was applied for the preparation of novel 5(R)- and 5(S)-methylmorpholin-2-ones starting from the corresponding enantiopure 2-(hydroxymethyl)aziridines. Additionally, 2-(methoxymethyl)- and 2-(phenoxymethyl)aziridines were treated with LiAlH4 under microwave irradiation, giving rise to either isopropylamines or 1-methoxypropan-2-amines depending on the reaction conditions
    corecore