HOCA at home – en casa – zu hause – a casa – em casa – à la maison

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Congrats for this new article!

Sulfonamide as amide isostere for fine-tuning the gelation properties of physical gels, Alegre-Requena, J. V.; Grijalvo, S.; Sampedro, D.;  Mayr, J.;  Saldías, C.; Marrero-Tellado, J. J.; Eritja, R.; Herrera, R. P.; Díaz, D. D. RSC Adv. 2020, 10, 11481-11492.

Abstract. (S)-2-Stearamidopentanedioic acid (C18-Glu) is a known LMW gelator that forms supramolecular gels in a variety of solvents. In this work, we have carried out the isosteric substitution of the amide group by a sulfonamide moiety yielding the new isosteric gelator (S)-2-(octadecylsulfonamido)pentanedioic acid (Sulfo-Glu). The gelation ability and the key properties of the corresponding gels were compared in terms of gelation concentration, gel-to-sol transition temperature, mechanical properties, morphology, and gelation kinetics in several organic solvents and water. This comparison was also extended to (S)-2-(4-hexadecyl-1H-1,2,3-triazol-4-yl)pentanedioic acid (Click-Glu), which also constitutes an isostere of C18-Glu. The stabilizing interactions were explored through computational calculations. In general, Sulfo-Glu enabled the formation of non-toxic gels at lower concentrations, faster, and with higher thermal-mechanical stabilities than those obtained with the other isosteres in most solvents. Furthermore, the amide-sulfonamide isosteric substitution also influenced the morphology of the gel networks as well as the release rate of an embedded antibiotic (vancomycin) leading to antibacterial activity in vitro against Staphylococcus aureus.

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Happy birthday Raquel!

One more year… and getting younger!

Sara, Maru, Esther, Guillermo, Raquel, Conchita, Fer, Sandra, Fanny and Jacopo.

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Working and relaxing…

… both are compatible and necessary to enjoy life 😉

 

Very nice and instructive seminar by Fer…

and delicious Mexican food!

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Just accepted, congratulations!

Asymmetric organocatalyzed aza‐Henry reaction of hydrazones: experimental and computational studies, Sonsona, I. G.; Alegre-Requena, J. V.; Marqués-López, E.; Gimeno, M. C.; Herrera, R. P. Chem. Eur. J. 2020, DOI: 10.1002/chem.202000232

 

Abstract. The first asymmetric catalyzed aza‐Henry reaction of hydrazones is presented. In this process, quinine was used as the catalyst to synthesize different alkyl substituted β‐nitrohydrazides with ee up to 77%. This ee was improved up to 94% by a further recrystallization and the opposite enantiomer can be obtained using quinidine as catalyst, opening exciting possibilities in fields where the control of chirality is vital, such as the pharmaceutical industry. Additionally, experimental and ab initio studies were performed to understand the reaction mechanism. The experimental results revealed an unexpected secondary kinetic isotope effect (KIE) that is explained by the calculated reaction pathway, which shows that the protonation of the initial hydrazone and the C‐C bond forming reaction occur during a concerted process. This concerted mechanism makes the catalysis conceptually different to traditional base‐promoted Henry and aza‐Henry reactions.

Posted in Computational chemistry, Eugenia Marqués-López, Henry, Organocatalysis, Publication, Raquel P. Herrera | Tagged , , , , , , , , , , | Leave a comment

Approaching dangerously the ENZYMES…

Dr. Juan Mangas-Sanchez, visited us and gave an interesting talk about New enzymes for the preparation of amines. Discovery, directed evolution and synthetic applications.

Juan is currently working as a Post-Doctoral Research Assistant at the Manchester Institute of Biotechnology, integrated in Turner Lab. He will be incorporated at ISQCH very soon, after being appointed as an ARAID researcher. Then, Juan will be an HOCA member and we will work together with Gimenos’s Group, looking for convergence, synergies and much more, between ORGANOCATALYSIS, BIOCATALYSIS and METAL CATALYSIS.

Thank you for your visit and welcome to Zaragoza!!

 

Maru, Juan, Raquel and Conchita (Faculty of Science, UZ – 23/02/2020).

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First fruit of a very interesting collaboration…

… with Dr. Santiago Uriel.

Thank you and congratulations!

Simple iodoalkyne-based organocatalysts for the activation of carbonyl compounds, Alegre-Requena, J. V.; Valero-Tena, A.; Sonsona, I. G.; Uriel, S.; Herrera, R. P. Org. Biomol. Chem. 2020, DOI: 10.1039/c9ob02688f

Abstract. A novel approach for the formation of bisindolylmethane derivatives (BIMs) is described as a proof of concept to evaluate the catalytic capacity of iodoalkynes. The use of these derivatives is reported as an example of simple halogen bond-based organocatalyst. This kind of activation has not been used before for the synthesis of bisindolylmethane derivatives 3. Interestingly, the preparation of 3-(1H-indol-3-yl)-1-phenylbutan-1-one (8) has been also achieved for the first time with an iodoalkyne derivative. We prove the efficiency of this family of new catalysts by developing a simple and easy operational methodology, opening the door to the development of alternative catalysts in the area of halogen bond-based organocatalysts.

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Hot paper Chem. Eur. J. – Congratulations!

Thiolate Bridged Gold(I)–NHC Catalysts: New Approach for Catalyst Design and its Application to Trapping Catalytic Intermediates

Renso Visbal, Raquel P. Herrera* and M. Concepción Gimeno*

Chem. Eur. J. 2019, 25, 15837–15845.

More info (in Spanish).

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Santa Claus is coming to HOCA town!

We said hello to Christmas and goodbye to Manel and Athar.

Thank you for coming to work with us. Safe trip back home and good luck!

Merry Christmas everyone!

 

    

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Drugs: Dr. Jekyll and Mr. Hyde

True to its commitment to scientific dissemination, last week, Raquel told to a general public, both, adults (December 12): Ámbito cultural (El Corte Inglés), and young people (December 13): IES Goya (Zaragoza), about the different properties that can show the two enantiomers of drugs containing quaternary carbons.

Everybody enjoyed once more the Raquel’s natural communicative skills!

 

 

 

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