1,721,004 research outputs found
Enantioselective organocatalytic approaches to active pharmaceutical ingredients - Selected industrial examples
No full textCatalysis is, often, the preferred approach to access chiral molecules in enantioenriched form both in academia and in industry; nowadays, organocatalysis is recognised as the third pillar in asymmetric catalysis, along with bio- and metal-catalysis. Despite enormous advancements in academic research, there is a common belief that organocatalysis is not developed enough to be applicable in industry. In this review, we describe a selection of industrial routes and their R&D process for the manufacture of active pharmaceutical ingredients, highlighting how asymmetric organocatalysis brings added value to an industrial process. The thorough study of the steps, driven by economic stimuli, developed and improved chemistry that was, otherwise, believed to not be applicable in an industrial setting. The knowledge discussed in the reviewed papers will be an invaluable resource for the whole research community
Enantioselective organocatalytic approaches to active pharmaceutical ingredients - selected industrial examples
No full textCatalysis is, often, the preferred approach to access chiral molecules in enantioenriched form both in academia and in industry; nowadays, organocatalysis is recognised as the third pillar in asymmetric catalysis, along with bio- and metalcatalysis. Despite enormous advancements in academic research, there is a common belief that organocatalysis is not developed enough to be applicable in industry. In this review, we describe a selection of industrial routes and their RandD process for the manufacture of active pharmaceutical ingredients, highlighting how asymmetric organocatalysis brings added value to an industrial process. The thorough study of the steps, driven by economic stimuli, developed and improved chemistry that was, otherwise, believed to not be applicable in an industrial setting. The knowledge discussed in the reviewed papers will be an invaluable resource for the whole research community
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Advancements in the recycling of organocatalysts: From classical to alternative approaches
No full textHomogenous catalysis is a fundamental tool in chemistry and holds a key role to build a sustainable future. This review covers a range of different approaches that have been devised, in the past couple of years, to recycle and reuse the homogenous catalysts, to improve the environmental and economic footprint. The organic catalysts have been supported on organic, inorganic and magnetic matrixes, to allow easy separation and recycle. Additional ingenious solutions have been designed; researchers exploited supramolecular interactions, change of phase, pH, temperature or membranes to address some of the issues that arise with heterogenous catalysis and to facilitate the recovery process
Comportamento dei linfociti T teofillino-sensibili nell'epatite da virus A, B, non-A,non-B. II. Aspetti applicativi
No full textOrganocatalyzed Michael addition to nitroalkenes via masked acetaldehyde
Full text linkA novel and safe reaction protocol for the enantioselective enamine-catalysed addition of acetaldehyde to nitroalkenes is presented; this protocol makes use of a safe acetaldehyde precursor to access important intermediates to Active Pharmaceutical Ingredients (APIs), and allows the use of fewer equivalents of acetaldehyde and lower catalyst loadings. The reaction developed proved to be suitable to be performed on gram-scale and to produce key intermediates for the synthesis of pharmacologically active compounds such as pregabalin
Comportamento dei linfociti T teofillino-sensibili nell'epatite da virus A, B, non-A,non-B. I.Aspetti metodologici
No full textInfluence of structurally related micelle forming surfactants on the antioxidant activity of natural substances
No full textPhysicochemical properties of micelles, like other lipid aggregates, mostly depend on the composition and on the structure of the surfactants used as monomers. The preparation and the characterization of three cationic L-prolinol derivative surfactants with different chain lengths and their corresponding N-oxide are described. UV measurements were carried out to investigate the effect of the inclusion in micelles on the degradation of L-ascorbic acid and (+)-usnic acid. An influence on antioxidant activity was exerted to an extent strictly dependent on i) surfactant chain length, ii) charge, iii) pH (in the case of (+)-usnic acid) and iv) on the hydrophilicity of the solute, determinant parameter for their location in the aggregates. In general the extent of the antioxidant activity of the system in the case of N-oxides micelles depends on surfactant chain length. On the other hand, cationic micelles formed by the surfactant with the shortest chain behave more like N-oxides ones rather than those formed by its relative structural homologues featuring longer alkyl chains, probably as a consequence of a concentration effect
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