Proline derivatives incorporating hydrophobic long-chain derived from natural and synthetic fatty acids

The α-hydrophobic long chain-α-amino esters are prepared by α-hydroxylation of a series of fatty acid esters [derived from oleic acid (OA), linoleic acid (LA), arachidonic acid (ARA) and docosahexaenoic acid (DHA)] followed by Mitsunobu reaction and hydrazinolysis of the phthalimide. These amino esters are mixed with aldehydes and electrophilic alkenes to give very good chemical yields and diastereoselectivities of prolinate derivatives incorporating a hydrophobic long chain at the α-position. This multicomponent 1,3-dipolar cycloaddition (1,3-DC) takes place at room temperature. The synthesis of the homologue hydrophobic chain of OA is performed by its oxidation to aldehyde/racemic N-tert-butylsulfinyl imine/Neff reaction. Final 1,3-DC with benzaldehyde and N-methylmaleimide affords homologue prolinate derivative in good yield.We gratefully acknowledge financial support from the Spanish Ministerio Ministerio de Ciencia, Innovación y Universidades (projects CTQ2013-43446-P and CTQ2014-51912-REDC), the Spanish Ministerio de Economía, Industria y Competitividad, Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER, EU) (projects CTQ2016-76782-P and CTQ2016-81797-REDC), the Generalitat Valenciana (PROMETEOII/2014/017), Medalchemy, S. L. and the University of Alicante. E. S.-M. thanks Medalchemy, S. L./UA for a predoctoral fellowship

Synthesis of pharmacophores containing a prolinate core using a multicomponent 1,3-dipolar cycloaddition of azomethine ylides

A multicomponent 1,3-dipolar cycloaddition between heterocyclic aldehydes, amino esters and dipolarophiles is efficiently promoted by silver acetate as catalyst, and depending on the nature of the heterocycle and its reactivity the reaction requires 70 °C or rt to complete. Selected pharmacophores anchored to a formyl group are chromone, 5-methoxyindole, pyridoxal surrogates and a very attractive uracyl derivative. The preference of each tested amino esters towards different dipolarophiles is discussed. At the end, a selective reduction of the ester group allows to obtain a very interesting dideoxiazanucleoside derivative.We gratefully acknowledge financial support from the Spanish Ministerio de Ciencia e Innovación (MICINN) (projects CTQ2010-20387 and Consolider Ingenio 2010, CSD2007-00006), the Spanish Ministerio de Economía y Competitividad (MINECO) (projects CTQ2013-43446-P and CTQ2014-51912-REDC), the Spanish Ministerio de Economía, Industria y Competitividad, Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (projects CTQ2016-76782-P and CTQ2016-81797-REDC), the Generalitat Valenciana (PROMETEO2009/039 and PROMETEOII/2014/017), the University of Alicante and Medalchemy S. L. E. Selva thanks Univerisdad de Alicante and Medalchemy S. L. for a predoctoral fellowship

Synthesis of Allylic Amines by Asymmetric Transfer Hydrogenation of α,β-Unsaturated N-(tert-Butylsulfinyl)imines

Primary allylic amines with enantiomeric excesses from 97 to >99% were prepared by asymmetric transfer hydrogenation of α,β-unsaturated N-(tert-butylsulfinyl)ketimines followed by removal of the sulfinyl group. The effect caused by different substituents at the C═C bond and at the iminic carbon atom on the chemoselectivity of the reduction was studied. The desired enantiomer of the final allylic amine can be synthesized by choosing the sulfinyl group with the appropriate absolute configuration.This work was generously supported by the Spanish Ministerio de Ciencia e Innovación (MICINN; Grant CTQ2011-24151), the Spanish Ministerio de Economía, Industria y Competitividad (Grant CTQ2015-66624-P), and the University of Alicante. E.S. thanks the University of Alicante for a predoctoral fellowship. O.P. thanks the Spanish Ministerio de Educación for a predoctoral fellowship (Grant AP-2008-00989)

Sequential Metal-Free Thermal 1,3-Dipolar Cycloaddition of Unactivated Azomethine Ylides

The thermal 1,3-dipolar cycloaddition of unactivated azomethine ylides derived from allylamine and aromatic or heteroaromatic aldehydes with maleimides and 1,1- and 1,2-bis­(phenylsulfonyl)­ethylene affords <i>endo</i>-2,5-<i>trans</i> cycloadducts in moderate to good yields. DFT calculations provide evidence that the diastereoselectivity observed depends on the isomerization between S- and W-ylides according to Curtin-Hammett’s principle. DFT calculations also explain the different diastereomeric ratio observed for 2-pyridyl and 2-thienyl derivatives in which the isomerization is not possible due to the competitiveness between isomerization barrier and the rate-limiting step (ylide formation barrier). This methodology is applied to the diastereoselective synthesis of a tricyclic thrombin inhibitor

Synthesis of Allylic Amines by Asymmetric Transfer Hydrogenation of α,β-Unsaturated <i>N</i>‑(<i>tert</i>-Butylsulfinyl)imines

Primary allylic amines with enantiomeric excesses from 97 to >99% were prepared by asymmetric transfer hydrogenation of α,β-unsaturated <i>N</i>-(<i>tert</i>-butyl­sulfinyl)­ketimines followed by removal of the sulfinyl group. The effect caused by different substituents at the CC bond and at the iminic carbon atom on the chemoselectivity of the reduction was studied. The desired enantiomer of the final allylic amine can be synthesized by choosing the sulfinyl group with the appropriate absolute configuration

Effects of a polysaccharide-based multiingredient supplement on salivary immunity in non-elite marathon runners

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Salivary immunity and lower respiratory tract infections in non-elite marathon runners

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