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226 results on '"Leardini, Rino"'

1. Radical reduction of aromatic azides to amines with tributylgermanium hydride

Author

Benati, Luisa, Bencivenni, Giorgio, Leardini, Rino, Minozzi, Matteo, Nanni, Daniele, Spagnolo, Piero, Scialpi, Rosanna, and Zanardi, Giuseppe

Subjects
Germanium -- Electric properties, Chemical reactions -- Research, Aldehydes -- Electric properties, Biological sciences, Chemistry
Abstract

Aromatic azides are inert toward tributylgermanium hydride under thermal conditions in the absence and in the presence of a radical initiator but in the presence of catalytic amounts of benzenethiol undergo fast reaction, yielding reduced anilines and 2-germylated derivatives in high overall yields. A novel PhSH-catalyzed radical chain reaction of tributylgermanium hybride with aryl azides discovered.

Published
2006

2. Stereomutation and cryogenic enantioseparation of conformational antipodes of hindered aryl oximes

Author

Gasparrini, Francesco, Grilli, Stefano, Leardini, Rino, Lunazzi, Lodovico, Mazzanti, Andrea, Nanni, Daniele, Pierini, Marco, and Pinamonti, Marco

Subjects
Chemistry, Organic -- Research, Nuclear magnetic resonance spectroscopy -- Usage, Halogens -- Physiological aspects, Atoms -- Physiological aspects, Oxygen -- Physiological aspects, Biological sciences, Chemistry
Abstract

Research has been conducted on the O-alkyl benzyl aryl oximes with the halogen atoms in the ortho position. The hypothesis that the corresponding conformational antipodes may interconvert to allow their physical separation has been investigated via the dynamic NMR study and the results are presented.

Published
2002

3. Stereomutation of conformational atropisomers of o-tert-butylphenyl alkyl ketones

Author

Leardini, Rino, Lunazzi, Lodovico, Mazzanti, Andrea, and Nanni, Daniele

Subjects
Chemistry, Organic -- Research, Gene mutations -- Physiological aspects, Ketones -- Genetic aspects, Carbon -- Physiological aspects, Oxygen -- Physiological aspects, Argon -- Physiological aspects, Biological sciences, Chemistry
Abstract

Research has been conducted on the unhindered aryl ketones. The synthesis of the aryl alkyl ketones where the tert-butyl substituent severely hinders the Ar-CO rotation process has been carried out and investigated and the results are discussed.

Published
2001

4. Radical addition to isonitriles: a route to polyfunctionalized alkenes through a novel three-component radical cascade reaction

Author

Leardini, Rino, Nanni, Daniele, and Zanardi, Giuseppe

Subjects
Organic compounds -- Research, Radicals (Chemistry) -- Analysis, Olefins -- Research, Chemical reactions -- Analysis, Isomerization -- Analysis, Biological sciences, Chemistry
Abstract

The photolysis of aromatic disulfides in the presence of alkynes and isonitriles results in the production of a novel three-component radical cascade reaction, which involves the addition of a sulfanyl radical to the alkyne followed by the addition of the vinyl radical produced to the isonitrile.

Published
2000

5. Synthesis and calibration of two radical timing devices: 2-methyl-2-(1-naphthyl)- and 2-methyl-2-(2-naphthyl)-1-bromopropane

Author

Leardini, Rino, Lucarini, Marco, Pedulli, Gian Franco, and Valgimigli, Luca

Subjects
Free radical reactions -- Research, Automatic timers -- Research, Biological sciences, Chemistry
Abstract

The synthesis of 2-methyl-2-(1-naphthyl)-1-bromopropane and of 2-methyl-2-(2 naphthyl)-1-bromopropane that can generate the radicals 2-methyl-2-(1-naphthyl)-1-propyl and 2-methyl-2-(2-naphthyl)-1-propyl and the calibration of their rearrangement reactions was described. The rearrangement of the radicals at room temperature with rate constants of 6.4 x 10 to the third power and 1.4 x 10 to the fourth power M-1s-1, respectively, can be valuable in determining rate constants for hydrogen abstraction by primary alkyl radicals.

Published
1999

6. Alpha-(arylthio)imidoyl radicals: (3 + 2) radical annulation of aryl isothiocyanates with 2-cyano-substituted aryl radicals

Author

Leardini, Rino, Nanni, Daniele, Pareschi, Patrizia, Tundo, Antonio, and Zanardi, Giuseppe

Subjects
Radicals (Chemistry) -- Research, Aromatic compounds -- Research, Ring formation (Chemistry) -- Research, Biological sciences, Chemistry
Abstract

An unusual cascade radical reaction of aryl isothiocyanates and 2-cyanoaryl radicals was observed. The procedure involves the formation of an alpha-(arylthio)imidoyl radical, a 5-exo-dig cyclization onto a cyano group and a final 6-membered ring closure of an iminyl radical. The competitive 5-membered spiro-cyclization of the iminyl, resulting into an isomeric product, was only seen in the case of a disubstituted aryl isothiocyanate. The whole procedure entails a rare example of (3 + 2) radical annulation and permits the one-pot synthesis of tetracondensed nitrogen heterocycles in good yields.

Published
1997

7. Novel rearrangement of N-(9H-carbazol-9-yl)arylaminyl radicals

Author

Leardini, Rino, Lucarini, Marco, Nanni, Alessandro, Nanni, Daniele, Pedulli, Gian Franco, Tundo, Antonio, and Zanardi, Giuseppe

Subjects
Rearrangements (Chemistry) -- Methods, Radicals (Chemistry) -- Spectra, Organic compounds -- Synthesis, Biological sciences, Chemistry
Abstract

N-(9H-carbazol-9-yl)arylaminyl radicals were derived from 2-(arylazo)-2'-iodobiphenyls using the tin hydride method. The radical was reduced by a hydride to produce N-(9H-carbazol-9-yl)arylamine. Alternatively, it can attack the carbonyl moiety by a 5-exo cyclization to pproduce an intermediate. This led to an arlozy radical by ring opening and ultimately to the rearranged product by hydrogen abstraction. Evidences of this mechanism was determined by EPR spectroscopy.

Published
1993

8. Annulation reactions with iron(III) chloride: oxidation of imines

Author

Leardini, Rino, Nanni, Daniele, Tundo, Antonio, Zanardi, Giuseppe, and Ruggieri, Fabrizio

Subjects
Organic compounds -- Synthesis, Quinone -- Research, Ferric chloride -- Research, Aromatic compounds, Heterocyclic compounds -- Research, Oxidation-reduction reaction -- Methods, Biological sciences, Chemistry
Abstract

Reaction of aryl imines with phenylacetylene or styrene in an acetonitrile solution of iron(III) chloride yields quinolines and tetrahydroquinolines. The formation of heterocyclic rings from imines via one-electron oxidation with iron(III) provides a peroxide-free synthetic route to quinoline. Arylamino benzenes are also produced in various mixes, but in the presence of stoichiometric levels of chloranil only quinolines are produced. The mechanism involves formation of imidolyl intermediates via abstraction of hydrogen from the imines.

Published
1992

9. Reaction of azoarenes with tributyltin hydride

Author

Alberti, Angelo, Bedogni, Nicola, Benaglia, Massimo, Leardini, Rino, Nanni, Daniele, Pedulli, Gian Franco, Tundo, Antonio, and Zanardo, Giuseppe

Subjects
Aromatic compounds, Inorganic compounds -- Research, Tributyltin -- Research, Biological sciences, Chemistry
Abstract

Tributyltin hydride causes the reduction of azoarenes giving substituted hydrazyls in desired amounts and selectivity. Reactions involving the reduction of azoarenes with ortho substituents to the azo function, produce heterocyclic compounds of low selectivity. Whereas, reactions involving stannyl free radicals and azoarenes require the presence of a radical initiator such as alpha,alpha'-azobis(isobutyronitrile), so that reactions follow a radical chain mechanism.

Published
1992

12. Iminyl radicals from [alpha]-azido o-iodoanilides via 1,5-H transfer reactions of aryl radicals: new transformation of [alpha]-azido acids to decarboxylated nitriles

Author

Bencivenni, Giorgio, Lanza, Tommaso, Leardini, Rino, Minozzi, Matteo, Nanni, Daniele, Spagnolo, Piero, and Zanardi, Giuseppe

Subjects
Azo compounds -- Chemical properties, Elimination reactions -- Analysis, Nitriles -- Chemical properties, Biological sciences, Chemistry
Abstract

The radical reaction of tributyline hydride with o-iodo-N-methylanilides derived from [alpha]-azido acids as an excellent access to [alpha]-(aminocarbonyl)iminyl radicals is demonstrated. The iminyls obtained exhibit a tendency to form corresponding nitriles by [beta]-elimination of aminocarbonyl radicals.

Published
2008

13. Generation and cyclization of unsaturated carbamoyl radicals derived from S-4-pentynyl carbamothioates under tin-free conditions

Author

Benati, Luisa, Bencivenni, Giorgio, Leardini, Rino, Minozzi, Matteo, Nanni, Daniele, Scialpi, Rosanna, Spagnolo, Piero, and Zanardi, Giuseppe

Subjects
Isocyanates -- Chemical properties, Ring formation (Chemistry) -- Analysis, Carbamates -- Chemical properties, Biological sciences, Chemistry
Abstract

A new, valuable tin-free protocol is devised for the generation of carbamoyl radicals using accessible S-4-pentynyl carbamothioate precursors. Evidence is given that N-tosyl-substituted carbamoyl radicals display a peculiar tendency to yield the corresponding isocyanate by beta-elimination of the tosyl radical.

Published
2006

14. Thermal reactions of tributyltin hydride with alpha-azido esters: Unexpected intervention of tin triazene adducts under both nonracial conditions

Author

Benati, Luisa, Scialpi, Rosanna, Bencivenni, Giorgio, Spagnolo, Piero, Leardini, Rino, Zanardi, Giuseppe, Minnozi, Matteo, and Nanni, Daniele

Subjects
Amines -- Chemical properties, Benzene -- Chemical properties, Esters -- Chemical properties, Biological sciences, Chemistry
Abstract

The thermal reaction of various alpha-azido esters with Bu3SnH in refluxing benzene results in smooth production of 3-(tributylstannyl)-1-triazene adducts affording cyclized 1,2,3-triazol-4-ones in preference to reduced amines. Hence, it provides a useful method for the preparation of triazole derivatives.

Published
2005

15. Generation of highly acidic sp (super)3 carbons in pyrroles and indoles

Author

Guidotti, Simona, Camurati, Isabella, Focante, Francesca, Angellini, Luca, Moscardi, Gilberto, Resconi, Luigi, Leardini, Rino, Nanni, Daniele, Mercandelli, Pierluigi, Sironi, Angelo, Beringhelli, Tiziana, and Maggioni, Daniela

Subjects
Chemistry, Organic -- Research, Organic compounds -- Composition, Reactivity (Chemistry) -- Analysis, Cyclic compounds -- Composition, Pyrrole, Acids, Carbon compounds, Biological sciences, Chemistry
Abstract

Research has been conducted on pyrroles and indoles. The authors describe the reaction of these compounds with (C (sub)6 F (sub)5) (sub)3 and BCl (sub)3 which affords B-N complexes with acidic sp (super)3 carbons.

Published
2003

16. Cascade radical reactions via alpha-(arylsulfanyl)imidoyl radicals: competitive [4+2] and [4+1] radical annulations of alkynyl isothiocyanates with aryl radicals

Author

Benati, Luisa, Calestani, Gianluca, Leardini, Rino, Minozzi, Matteo, Nanni, Daniele, Spagnolo, Piero, Strazzari, Samantha, and Zanardi, Giuseppe

Subjects
Chemistry, Organic -- Research, Organic compounds -- Composition, Radicals (Chemistry), Chemical reactions -- Analysis, Isocyanates -- Composition, Biological sciences, Chemistry
Abstract

Research has been conducted on aryl radicals. The authors describe the radical cascade reaction of these compounds with 2-(2-phenylethynyl)phenyl isothiocyanate which entails alpha-(arylsulfanyl)imidoyl radicals leading to formation of thiochromeno[2,3-b]indoles.

Published
2003

17. Iminyl Radicals from α-Azido o-Iodoanilides via 1,5-H Transfer Reaction of Aryl radicals: New Transformation of α-Azido Acids to Decarboxylated Nitriles

Author

BENCIVENNI, GIORGIO, LANZA, TOMMASO, LEARDINI, RINO, MINOZZI, MATTEO, NANNI, DANIELE, SPAGNOLO, PIERO, ZANARDI, GIUSEPPE, G. Bencivenni, T. Lanza, R. Leardini, M. Minozzi, D. Nanni, P. Spagnolo, and G. Zanardi

Subjects
IMINYL RADICALS, RADICAL 1, ARYL RADICALS, 5-H TRANSFER REACTIONS, ALKANENITRILES, AZIDO ACIDS
Abstract

The radical reaction of tributyltin hydride with o-iodo-N-methylanilides derived from α-azido acids provides an excellent access to α-(aminocarbonyl)iminyl radicals through 1.5-hydrogen transfer reaction of initially formed aryl radicals followed by β-elimination of dinitrogen from ensuing α-azido-α-(aminocarbonyl)alkyls. The outcoming iminyl radicals display a peculiar tendency to form corresponding nitriles by β-elimination of aminocarbonyl radicals.

Published
2008

18. Riduzioni di Azidi ad Ammine con Idruri di Germanio ed Indio

Author

BENATI, MARIA LUISA, BENCIVENNI, GIORGIO, LEARDINI, RINO, MINOZZI, MATTEO, NANNI, DANIELE, SCIALPI, ROSANNA, SPAGNOLO, PIERO, ZANARDI, GIUSEPPE, L. Benati, G. Bencivenni, R. Leardini, M. Minozzi, D. Nanni, R. Scialpi, P. Spagnolo, and G. Zanardi

Subjects
POLARITY REVERSAL CATALYSIS, RIDUZIONI RADICALICHE, ARYL AZIDI, TRIBUTILGERMANIO IDRURO, ANILINE
Published
2005

20. Cyclisations of N-Stannylaminyl Radicals onto Nitriles: a new entry to pyrrolipyrroles and pyrrolopyridines

Author

BENATI, MARIA LUISA, BENCIVENNI, GIORGIO, LEARDINI, RINO, MINOZZI, MATTEO, NANNI, DANIELE, SCIALPI, ROSANNA, SPAGNOLO, PIERO, ZANARDI, GIUSEPPE, L. Benati, G. Bencivenni, R. Leardini, M. Minozzi, D. Nanni, R. Scialpi, P. Spagnolo, and G. Zanardi

Subjects
AZIDONITRILES, RADICAL CYCLIZATIONS, PYRROLOPYRIDINES, TRIBUTYLTIN HYDRIDE, PYRROLOPYRROLES
Abstract

The radical reaction of tributyltin hydride with azidoalkylmalononitriles bearing variously substituted alkenyl groups gives rise to pyrrolopyrroles and pyrrolopyridines through tandem cyclization reaction of initial stannylaminyl radicals onto either nitrile group followed by cyclization of ensuing aminoiminyl radicals onto the alkenylic moiety

Published
2004

21. Thioimidoyl Radicals as a Novel Tin-Free Source of Alkyl Radicals

Author

BENATI, MARIA LUISA, LEARDINI, RINO, MINOZZI, MATTEO, NANNI, DANIELE, SCIALPI, ROSANNA, SPAGNOLO, PIERO, STRAZZARI, SAMANTHA, ZANARDI, GIUSEPPE, J. C. Walton, L. Benati, R. Leardini, M. Minozzi, D. Nanni, R. Scialpi, P. Spagnolo, S. Strazzari, J. C. Walton, and G. Zanardi

Subjects
THIOIMIDOYL RADICALS, RADICAL GENERATION, ALKYL RADICALS, ISONITRILES, THIOLS
Abstract

The radical reaction of alkanethiols with tert-butyl isocyanide in boiling benzene gives rise to intermediate thioimidoyls radicals which undergo easy fragmentation yielding tert-butyl isothiocyanate and corresponding alkyl radicals. These reactions allow a new protocol for the generation of alkyl radicals under tin-free conditions.

Published
2004

22. Reazioni radicaliche a catena di tioesteri pentinilici con benzenetiolo: generazione e reattività di radicali acilici in assenza di idruri organici dello stagno e del silicio

Author

BENATI, MARIA LUISA, LEARDINI, RINO, MINOZZI, MATTEO, NANNI, DANIELE, SPAGNOLO, PIERO, SCIALPI, ROSANNA, ZANARDI, GIUSEPPE, L. Benati, R. Leardini, M. Minozzi, D. Nanni, P. Spagnolo, R. Scialpi, and G. Zanardi

Subjects
CICLIZZAZIONI RADICALICHE, CHETONI CICLICI, BENZENETIOLO, TIOESTERI PENTINILICI, RADICALI CARBAMMOILICI
Published
2004

42. Cyclizations of N-Stannylaminyl Radicals onto Nitriles.

Author

Benati, Luisa, primary, Bencivenni, Giorgio, additional, Leardini, Rino, additional, Minozzi, Matteo, additional, Nanni, Daniele, additional, Scialpi, Rosanna, additional, Spagnolo, Piero, additional, Zanardi, Giuseppe, additional, and Rizzoli, Corrado, additional

Published
2004
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43. Synthesis and Reactivity of (C6F5)3B−N-Heterocycle Complexes. 1. Generation of Highly Acidic sp3Carbons in Pyrroles and Indoles

Author

Guidotti, Simona, primary, Camurati, Isabella, additional, Focante, Francesca, additional, Angellini, Luca, additional, Moscardi, Gilberto, additional, Resconi, Luigi, additional, Leardini, Rino, additional, Nanni, Daniele, additional, Mercandelli, Pierluigi, additional, Sironi, Angelo, additional, Beringhelli, Tiziana, additional, and Maggioni, Daniela, additional

Published
2003
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