Santa Maria D.,University of Bío Bío |
Claramunt R.M.,University of Bío Bío |
Bobosik V.,Synkola |
Torralba M.C.,Complutense University of Madrid |
And 3 more authors.
Tetrahedron | Year: 2013
A total number of nineteen 2-arylbenzotriazoles related to the UV absorber Tinuvin P have been studied. Moreover, besides those bearing a 2′-hydroxy substituent, known to experience ESIPT (Excited-State Intramolecular Proton Transfer), we have also prepared three compounds having another ortho-hydroxy group at position 6′. The X-ray molecular structures of five key representatives have been determined and some important features related to their behavior discussed on the basis of solution and solid-state NMR, as well as B3LYP/6-311++G(d,p) computational results. © 2013 Elsevier Ltd. All rights reserved.
Sebesta R.,Comenius University |
Central European Journal of Chemistry | Year: 2014
Enantioselective organocatalytic Michael additions affords useful building blocks for many biologically and medicinally relevant compounds. Ionically-tagged diphenylprolinol silyl ether efficiently catalyzes several Michael additions of aldehydes to nitroalkenes in ionic liquids. The Michael additions work well in ionic liquids; yields up to 95% and enantioselectivities up to 95% ee were achieved. Furthermore, in some cases, the catalytic system was reusable. © Versita Sp. z o.o.
Hajzer V.,Synkola |
Latika A.,Synkola |
Durmis J.,Synkola |
Sebesta R.,Comenius University
Helvetica Chimica Acta | Year: 2012
Organocatalytic Michael addition of alkoxyacetaldehyde 1 to N-protected 2-nitroethene-1-amine 2 (Scheme2) is a key step in the synthesis of an important antiviral agent, oseltamivir. Screening of a large array of structurally diverse acids as potential promoters led to the identification of several useful acidic additives for this reaction (Tables1-4). Also other reaction parameters were investigated with the aim of improving the diastereoselectivity of the Michael addition, while maintaining high enantiomer purity and yield (Tables5 and 6). Copyright © 2012 Verlag Helvetica Chimica Acta AG, Zürich, Switzerland.