2,555 research outputs found
MOLECULES
No full textMolecules (ISSN 1420-3049; CODEN: MOLEFW) is the leading international peer-reviewed open access journal of chemistry. Molecules is published semi-monthly online by MDPI. OPEN ACCESS for readers, with article processing charges (APC) paid by authors or their institutions. Indexed by the Science Citation Index Expanded (Web of Science), MEDLINE (PubMed), Scopus and other databases. All manuscripts are peer-reviewed and a first decision provided to authors approximately 14 days after submission; acceptance to publication is undertaken in 2.3 days (median values for papers published in this journal in the second half of 2019). Sections: published in fifteen topical sections. Impact Factor: 3.060 (2018) ; 5-Year Impact Factor: 3.380 (2018
Amino-aza-heteroaromatics and tryptamine connected to azelayl chain: synthesis and biological activity
No full textSynthesis and biological evaluation of novel Apcin analogues as potential CDC20 inhibitors
No full textAryl diazonium salts and benzene derivatives bearing two electron-donor substituents: chemical and mechanistic behaviours
No full textThe reaction between benzene derivatives 1-4 and p-substituted benzenediazonium tetrafluoroborates 5a-c provided novel azo-coupling products in high yields under mild conditions. The monitoring of the reaction progress using 1H-NMR provided mechanistic information on both the relative reactivity of the reagents and the possibility to detect novel reaction intermediates
Trapping and analyzing Wheland-Meisenheimer sigma-complexes, usually labile and escaping intermediates
No full textFor many years our research group’s interest lies in the study of nucleophilic/electrophilic aromatic substitution reactions. We found that when strongly activated substrates are used for mechanistic studies, the classical rules related to the steps involved in this kind of reactions are not always followed. The steps involved in both reactions are the formation of sigma-complexes which are usually not isolable because of their instability, bringing them to a rapid conversion into substitution products.
However, when we used strongly activated species, namely superelectrophiles and supernucleophiles, we have been able to identify, and in some cases to isolate, the related Wheland, Meisenheimer or sigma-complexes that are contemporaneously Wheland and Meisenheimer intermediates. a,b These intermediates are moderately stable and have been identified at low temperature by NMR spectroscopy. On the basis of these findings, we recently developed another supernucleophilic compound (2,4-dipyrrolidinyl-1,3-thiazole (DPT)), which readily reacts with both superelectrophiles 4,6-dinitrotetrazolepyridine (DNTP) and 4,6-dinitrobenzofuroxan (DNBF) to form stable Wheland-Meisenheimer complexes (respectively WM1 and WM2) that we were able to isolate and crystallize, obtaining interesting information from their X-Ray diffraction analysis.2 A theoretical study of these reactions provided us important data about the reaction pathways and the great stability of these complexes.
Nowadays we are studying the reactivity of DPT towards other superelectrophiles to give more informations on the WM complexes and to investigate the mechanisms of aromatic substitution reactions.
. a) Boga, C.; Del Vecchio, E.; Forlani, L. Eur. J. Org. Chem. 2004, 1567–1671; b) Boga, C.; Del Vecchio, E.; Forlani, L.; Mazzanti, A.; Todesco, P. E. Angew. Chem. Int. Ed. 2005, 44, 3285–3289. 2. Forlani, L.; Boga, C.; Mazzanti, A.; Zanna, N. Eur. J. Org. Chem., in press
Stereoselective synthesis of 3,6-disubstituted-1,2-diaminocyclohexanes through ring closing metathesis of 4,5-diamino-1,7-octadienes derivatives
No full text3,6-Disubstituted-4,5-di[(S)-1-phenylethylamino]-1,7-octadienes with different configurations at the carbon stereocenters, were protected as dihydrochlorides or cyclic phosphorous diamides and then converted to (1R,2R)-3,6-disubstituted-1,2-diaminocyclohexanes through ruthenium-catalyzed ring closing metathesis and subsequent hydrogenolysis-hydrogenation steps
One-Pot Synthesis of 1-Alkenyl Derivatives of Phospholane and Phosphinane − New Classes of Compounds
No full textThe synthesis of the title compounds at room temperature in a one-pot reaction involves the transfer of a phosphorus atom from a benzothiadiphosphole to incoming nucleophilic bis- and mono-Grignard reagents
A green synthesis of quinoxalines and 2,3-dihydropyrazines
No full textQuinoxaline and dihydropyrazine derivatives were obtained in high yields by simple addition 1,2-diamines and 1,2-dicarbonyl compounds in water. In some cases, the products spontaneously precipitates from the reaction mixture, making it possible to recover and reuse the mother liquor for further condensations.
The very mild reaction conditions, the high yields of the
products and the absence of any catalyst make this
methodology an efficient and green route to quinoxalines and
dihydropyrazines
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