Mirella Scotton
University of Siena
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Featured researches published by Mirella Scotton.
Tetrahedron | 1992
Angela Maria Celli; Mirella Scotton; Alessandro Sega
Abstract The hetero-Diels-Alder reaction of 1-oxabutadienes 1a–c bearing electron-withdrawing groups with ethyl vinyl ether and 2,3-dihydrofuran gave the functionalized 5,6-dihydro-4H-pyrans 2a-c, 4c and 4H-4a, 5, 6, 6a-tetrahydrofuro[2,3-b]pyrans 5a-c and 6c. Cycloadducts 2a and 4c easily rearranged to furo[2,3-b]furans 3a, 3c and 9c and cycloadducts 5a and 6c to difuro[2,3-b:3′,4′-d]furans 7a, 7c and 8c. The stereochemistry of compounds 5c and 7a was determined by single crystal X-ray analysis. Relative configurations of the other compounds were established by nOe data. Some aspects of the reaction mechanisms are discussed.
Tetrahedron | 1989
Angela Maria Celli; Donato Donati; Mirella Scotton
Abstract Tetraacetylethylene (1) reacted with electron-withdrawing azo compounds to give spiro furan-pyrazoles. Their structure was confirmed by an X-ray crystallographic analysis on a derivative of the spiro furan-3(2H),5′(7′H)-pyrazolo 1,2-a∥1,2,4 triazole-1′,3′,6′-trione. The cycload-ducts show ring-open chain tautomerism.
Tetrahedron Letters | 1983
Giorgio Adembri; A. Camparini; Donato Donati; Stefania Fusi; Fabio Ponticelli; Mirella Scotton
Abstract N-benzyl-1,4-dihydronicotinamide dimerized on irradiation with λ=365nm across 2,3 and 5,6 double bonds to give the product I which closed to centro-symmetric cage dimer IV on further irradiation with λ⩽313nm.
Journal of The Chemical Society-perkin Transactions 1 | 1980
Stefano Chimichi; Rodolfo Nesi; Mirella Scotton; Carlo Mannucci; Giorgio Adembri
I.r., u.v., and 1H n.m.r. spectral evidence demonstrated that 5-(o-aminophenylcarbamoyl)pyridazine-4-carboxylic acid (4), for which the zwitterionic structure (4a) appeared the most likely in the solid state, existed in dimethyl sulphoxide solution nearly exclusively as 3′,4′-dihydro-3′-oxospiro[pyridazine-5(2H), 2′(1′H)-quinoxaline]-4-carboxylic acid (18). The equilibrium (4a)⇄(18) was strongly influenced by the nature of the solvent. A study of the behaviour of compounds (5)–(10) enabled us to establish that the spirocyclisation critically depends on both the nature of the substituents on the pyridazine ring and on the nucleophilicity of the group bonded to the phenyl ring.
Tetrahedron Letters | 1994
Giorgio Adembri; Angela Maria Celli; Lucia R. Lampariello; Mirella Scotton; Alessandro Sega
Abstract Reaction of 3,4-diacetyl-3-hexen-2,5-dione, 1, with alkyl or aryl primary amines, 2a–g, led to highly substituted 1H-Pyrrol-3(2H)-ones, 3a–g. The structure was established from a single crystal X-ray analysis of compound 3c.
Tetrahedron Letters | 1984
Giorgio Adembri; Donato Donati; Lucia R. Lampariello; Mirella Scotton; Alessandro Sega
Abstract The stereochemistry of (1a,4β,5a)-1,5-diacetyl-4-hydroxy-4-methylbicyclo[3.1.0]hexan-2-one, the main cycloadduct of 2,3-diacetyl-4-hydroxy-4-methylcyclopent-2-en-1-one and diazomethane, was unambiguously established from a single crystal X-ray analysis.
Journal of The Chemical Society-perkin Transactions 1 | 1974
Giorgio Adembri; Stefano Chimichi; Francesco De Sio; Rodolfo Nesi; Mirella Scotton
Diethyl pyridazine-4,5-dicarboxylate (II) and its 3,6-dimethyl derivative (XIV) cyclised with o-phenylenediamine in the presence of sodium hydride to give 6,11-dihydropyridazino[4,5-c][1,6]benzodiazocine-5,12-dione (III) and its 1,4-dimethyl derivative (XV), respectively. By heating under reduced pressure these compounds were dehydrated to the corresponding pyridazino[4′,5′:3,4]pyrrolo[1,2-a]benzimidazol-11-ones (XII) and (XX).Compound (III) reacted with diazomethane yielding a mixture of di-N-methyl (IV), NO-dimethyl (V), and di-O-methyl (VI) derivatives. Mild alkaline hydrolysis of the dione (III) afforded 5-(o-aminophenylcarbamoyl)-pyridazine-4-carboxylic acid (VII), which cyclised to 5-(benzimidazol-2-yl)pyridazine-4-carboxylic acid (VIII). Heating compound (III) with hexamethylphosphoric triamide gave NN-dimethyl-5-(benzimidazol-2-yl)pyridazine-4-carboxamide (XI).3,6-Dimethylpyridazine-4,5-dicarboxylic anhydride (XVI) reacted with o-phenylenediamine at room temperature to give 3,6-dimethyl-5-(o-aminophenylcarbamoyl)pyridazine-4-carboxylic acid (XVII), whereas when refluxed with the same reagent in acetic acid it afforded 2-(3,6-dimethylpyridazin-4-yl)benzimidazole (XVIII).
Journal of The Chemical Society-perkin Transactions 1 | 1982
Giuseppe Sbrana; Mirella Scotton; Leonardo Angeloni
9,9′-Bifluorenylidene-3,3′,6,6′-tetracarbonitrile (TCBF) and (3,6-dicyano-9H-fluoren-9-ylidene)propanedinitrile (TCPF) have been synthesized starting from 9-oxo-9H-fluorene-3,6-dicarbonitrile. A 2 : 1 charge transfer complex of TCPF with NNN′N′-tetramethyl-p-phenylenediamine has been obtained, and the electrical and spectral properties investigated. Conductivity measurements performed on polycrystalline samples gave a value of the order of 0.02Ω–1 cm–1. These results support the ability of this new acceptor in forming charge-transfer complexes with semiconducting properties.
Journal of The Chemical Society-perkin Transactions 1 | 1988
Elena Gaggelli; Gianni Valensin; Giorgio Adembri; Angela Maria Celli; Mirella Scotton; Alessandro Sega
The different behaviour of L-(+)-N-mandelyl-L-(–)-asparagine, N-mandelyl-2-amino-4-pentanoic acid and N-mandelyl-2-aminobutanoic acid towards acylation was considered. 13C and 1H n.m.r. non-selective and selective relaxation rates and 1H-{1H} n.O.e.s were taken to show that L(+)-N-mandelyl-L-(–)-asparagine assumes, in DMSO solution, a conformation quite different from that of the other two amino acids. In this conformation both lone pairs of the alcoholic oxygen were shown to be involved in hydrogen bonding and to be shielded in a way that makes approach of the acylating reagent difficult.
Journal of The Chemical Society-perkin Transactions 1 | 1985
Giorgio Adembri; Cecilia Anselmi; Lucia R. Lampariello; Mirella Scotton; Alessandro Sega
The 1H n.m.r. spectra of 1,5-diacetyl-4-hydroxy-4-methylbicyclo[3.1.0]hexan-2-ones (2) and (3) and diethyl 4-hydroxy-4-methyl-2-oxobicyclo[3.1.0]hexane-1,5-dicarboxylate (6) were determined in the presence of the shift reagent Eu(fod)3. The observed induced shifts provide evidence for the relative configuration of the asymmetric centres of these compounds.