1. Αποθετήριο Παραδοτέων Υποτρόφων Δράσεων ΕΣΠΑ Τριτοβάθμιας Εκπαίδευσης 2017-2023
2. Όλο το Αποθετήριο
3. Ερευνητικές ομάδες

Τύπος:	Αναρτημένη ανακοίνωση (poster)
Τίτλος:	Synthesis of amino-substituted fused oxazolocoumarins via Au/TiO2-catalyzed selective reduction of the corresponding nitro-derivatives in the presence of NaBH4
Μέλος ερευνητικής ομάδας:	[EL] Βλάχου, Ευαγγελία-Ειρήνη[EN] Vlachou, Evangelia-Eirini [EL] Μπαλαλάς, Θωμάς[EN] Balalas, Thomas [EL] Χατζηπαύλου, Δήμητρα[EN] Hadjipavlou-Litina, Dimitra
Επικεφαλής ερευνητικής ομάδας:	[EL] Λίτινας, Κωνσταντίνος[EN] Litinas, Κonstantinos
Ημερομηνία:	26/09/2021
Περίληψη:	Fused coumarin derivatives present interesting biological activities. Especially, fused oxazolocoumarins have been tested for their antioxidant [1], or photoreleasing of aminolevulinic acid [2] activities. Fused pyridocoumarins poccess biological activities as antimalarial [3], antioxidant [4], and wound-healing [5]. Pyridocoumarins are prepared from aminocoumarins through the one-pot Povarov reactions with aromatic aldehydes [6], the reactions with phenylacetylene and benzaldehydes under catalysis by Lewis acids [4,7]. The cycloisomerization of propargylaminocoumarins, prepared from aminocoumarins, followed by oxidation led also to pyridocoumarins under catalysis by AgSbF6 [8] or Au/nanoparticles [9]. In continuation of our interest on fused oxazolocoumarin [1,10] and pyridocoumarin [4,9] derivatives we would like to report here the synthesis of novel amino-substituted fused oxazolocoumarins through a selective reduction procedure, and the biological evaluation of the products. The reactions studied and the synthesized products are depicted in Schemes 1-2. The reactions of 5,7-dinitro-6-hydroxycoumarins 1a,b with p-tolylmethanols 2a-e catalyzed by Au/TiO2 under heating in a sealed tube, in analogy to our former work [10], resulted to the 7-nitro-substituted fused oxazolocoumarins 3a-j. Selective reduction of nitro-group by Au/TiO2 in the presence of NaBH4 as an H donor, following a recent publication for the use of Au-NPs in the reduction of nitroarenes to anilines [11], led in excellent yield to the amino-substituted derivatives 4a-j (Scheme 1). Scheme 1. Synthesis of 7-amino-2-aryl-7H-chromen[5,6-d]oxazol-7-ones 4a-j. Scheme 2. Synthesis of 8-amino-2-alkyl-4H-chromen[3,4-d]oxazol-4-ones 8a-e. The nitration of 3-akylamino-4-hydroxycoumarins 5a-e [1] with HNO3/H2SO4 led to the nitro-compound 6a-e. The cyclization/dehydration of the later with P2O5 in toluene under microwave irradiation, in analogy to our former work [1], resulted to the 8-nitro-substituted fused oxazolocoumarins 7a-e. The selective reduction of those compounds by Pd/C under H2 atmosphere gave the amino-substituted compounds 8a-e (Scheme 2). All the above referred reactions are performed in excellent yields in every step. In an effort for direct nitration of fused oxazolocoumarins, the nitration of 2-methyl-4H-chromen[3,4-d]oxazol-4-one with HNO3/H2SO4 or with Cu(NO3)2.3H2O/H2SO4 was tried. In both cases the expected 7a was received in only ~20% yield, while the compound 6a was isolated in ~64% yield upon hydrolysis under the reaction conditions. Since coumarin derivatives are reported as antioxidant and anti-inflammatory agents [1,12], the new nitro-compounds 3a-j and 7a-e, as well as the new amino-compounds 4a-j and 8a-e were tested as possible antioxidants and as inhibitors of soybean lipoxygenase.
Γλώσσα:	Αγγλικά
Τόπος δημοσίευσης:	Θεσσαλονίκη, Ελλάδα
Σελίδες:	2
Θεματική κατηγορία:	[EL] Οργανική χημεία[EN] Organic Chemistry
Λέξεις-κλειδιά:	fused coumarins; Gold nanoparticles; Reduction; Antioxidant activity
Κάτοχος πνευματικών δικαιωμάτων:	© The Author(s) 2021.
Σχετίζεται με:	4-Amino-2-(p-tolyl)-7H-chromeno[5,6-d]oxazol-7-one 2,9-Dimethyl-4H-oxazolo[5',4':4,5]pyrano[3,2-f]quinolin-4-one
Τίτλος πηγής δημοσίευσης:	5th EuChemS Conference on Green and Sustainable Chemistry (5th EuGSC) Conference Proceedings
Σελίδες τεκμηρίου (στην πηγή):	389-390
Όνομα εκδήλωσης:	5th European Conference on Green and Sustainable Chemistry-26-29 September 2021-Virtual Conference-Conference Proceedings
Τοποθεσία εκδήλωσης:	Thessaloniki, Greece
Ημ/νία έναρξης εκδήλωσης:	26/09/2021
Ημ/νία λήξης εκδήλωσης:	29/09/2021
Σημειώσεις:	Human Resources Development, Education and Lifelong Learning", EDBM103, “Synthesis of Fused Pyranoquinolinone Derivatives with possible Biological Interest” (MIS: 5066801) "Support for researchers with emphasis on young researchers-cycle B”, (NSRF 2014-2020), (KA1020216). “This research is co-financed by Greece and the European Union (European Social Fund- ESF) through the Operational Programme «Human Resources Development, Education and Lifelong Learning 2014-2020» in the context of the project “Synthesis of Fused Pyranoquinolinone Derivatives with possible Biological Interest” (MIS 5066801).”
Εμφανίζεται στις συλλογές:	Ερευνητικές ομάδες