Lucedio Greci - Academia.edu (original) (raw)

Papers by Lucedio Greci

Research paper thumbnail of Antioxidant activity of NADH and its analogue--an in vitro study

Journal of biochemistry and molecular biology, Jan 31, 2004

The antioxidant activities of NADH and of its analogue, 1,4-dihydro-2,6-dimethyl-3,5-dicarbethoxy... more The antioxidant activities of NADH and of its analogue, 1,4-dihydro-2,6-dimethyl-3,5-dicarbethoxy-pyridine (PyH(2)), were evaluated in vitro. NADH was found to be oxidized by the peroxyl radical derived from 2,2-azobis-(2-amidinopropane) dihydrochloride (AAPH) decomposition, in a pH-dependent manner. Both NADH and PyH(2) inhibited the peroxidation of egg yolk lecithin (EYL) liposomes, although PyH(2) was more effective than NADH when 2,2'-azobis-4-methoxy-2,4-dimethyl-valeronitrile (methoxy-AMVN) was employed to induce EYL liposome peroxidation. The antioxidant activities of NADH and PyH(2) were also evaluated by measuring their influences on 1,3-diphenylisobenzofuran (DPBF) fluorescence decay in the presence of peroxyl radicals. NADH and PyH(2) were much more effective at inhibiting DPBF quenching in Triton X-100 micelles than in liposomes. These results indicate that NADH can inhibit lipid peroxidation despite being hydrophilic. Nevertheless, membrane penetration is an importa...

Research paper thumbnail of Synthesis and structural characterization of the first metal complex with an indole nitroxide

Research paper thumbnail of Structure of N-methanesulfonyl-N-phenylhydroxylamine from Fenton's reagent on nitrosobenzene in DMSO

Acta Crystallographica Section C Crystal Structure Communications

independent observed reflections. The SO2 group in the methanesulfonylhydroxylamine moiety adopts... more independent observed reflections. The SO2 group in the methanesulfonylhydroxylamine moiety adopts an orientation such that the N lone-pair bisects the O-SO angle. Significant deviation from coplanarity is observed in the benzene ring.

Research paper thumbnail of Conformational study on 4-(dimethylamino)methanesulfonanilides. 1. Structures of 2-methanesulfonyl- (I), 3-methanesulfonyl- (II) and 2-methanesulfonyl-3-methyl-4-(dimethylamino)methanesulfonanilide (III)

Acta Crystallographica Section C Crystal Structure Communications

Research paper thumbnail of X-ray study of 3-tert-butyl-1-methyl-2-phenylindole, the product of an unexpected tert-butylation reaction

Acta Crystallographica Section C Crystal Structure Communications

A(Cu Ka) = 1"5418/~, /x = 4"6 cm-~, F(000) = 1136, T=293 K, final R=0.052 for 1755 symmetryindepe... more A(Cu Ka) = 1"5418/~, /x = 4"6 cm-~, F(000) = 1136, T=293 K, final R=0.052 for 1755 symmetryindependent observed reflections. The indole nucleus adopts an almost planar conformation with a dihedral angle between the mean planes of the two

Research paper thumbnail of An Unconventional Approach to Photomobile Composite Polymer Films

Advanced materials (Deerfield Beach, Fla.), 2017

Photomobile polymer (Pmp) films are fabricated by using a cheap and fast process. The working mec... more Photomobile polymer (Pmp) films are fabricated by using a cheap and fast process. The working mechanism of the Pmp-film motion under illumination is explained. Details concerning the film structure and formation are given. Two related applications regarding light-induced caterpillar-miming motion and photocontrolled electrical switches are proposed.

Research paper thumbnail of Action of quinolinic and indolinonic aminoxyls as radical-scavenging antioxidants

Chemistry and Physics of Lipids, May 31, 1999

The kinetic studies on the actions of quinolinic and indolinonic aminoxyls in the oxidation of li... more The kinetic studies on the actions of quinolinic and indolinonic aminoxyls in the oxidation of lipid peroxidation induced by free radicals were carried out to evaluate their antioxidant activity. These aminoxyls showed a similar reactivity toward peroxyl radical with a-tocopherol. The antioxidant efficacies of aminoxyls against oxidation of methyl linoleate in homogeneous solution were smaller than that of a-tocopherol. Hydroxylamine, a reduced form of aminoxyl, possessed a comparative antioxidant efficacy with a-tocopherol and was capable of suppressing the consumption of a-tocopherol. Aminoxyls showed more potent antioxidant activity than a-tocopherol against the oxidation of methyl linoleate micelles induced by peroxyl radical or by a combination of copper ion and hydrogen peroxide. These results suggest that quinolinic and indolinonic aminoxyls may act as potent antioxidants against lipid peroxidation, especially in the presence of a good reductant which reduces aminoxyl radicals to hydroxylamines.

Research paper thumbnail of Alkoxyamines of Stable Aromatic Nitroxides: N?Ovs. C?O Bond Homolysis

Helv Chim Acta, 2006

A series of stable 2,2-disubstituted 3-(phenylimino)indol-1-oxyls, the alkoxyamines 3, were prepa... more A series of stable 2,2-disubstituted 3-(phenylimino)indol-1-oxyls, the alkoxyamines 3, were prepared, characterized, and tested as possible candidates in controlled radical polymerization (CRP). The sturctures of 3d and 10 were additionally solved by X-ray diffraction. The lability of the NÀO(C) and (N)OÀC bonds of compounds 3 were compared, and the possibility of NÀO vs. OÀC bond cleavage was evaluated by thermal degradation, ESR spin trapping, MS experiments, and DFT calculations. Alkoxyamines with a primary-or secondary-alkyl group bound to the O-atom of the nitroxide function (hexyl and i-Pr) mainly underwent (undesired) NÀO bond homolysis. When the O-alkyl radical was a tertiary or a benzyl group (crotonyl or styryl), OÀC bond cleavage occurred as the main process, thus suggesting a possible use of these compounds in CRP processes.

Research paper thumbnail of Fenton′s Reagent in Dimethyl Sulfoxide: An Unusual Sulfonylating System. X-Ray Crystallographic Analysis of 4-N,N-Dimethylamino-N,N- dimethanesulfonylaniline

Research paper thumbnail of UV-Filter combinations under UV-A exposure: Concomitant quantification of over-all spectral stability and molecular integrity

Journal of Photochemistry and Photobiology B Biology, May 25, 2007

Efficient UV-absorbing molecules are designed to protect against UV-light over-exposure. However,... more Efficient UV-absorbing molecules are designed to protect against UV-light over-exposure. However, upon UV exposure they may change spectral performance or act as photooxidants via generation of free radicals and reactive oxygen species alone or in combination with others. Therefore, information about their photointegrity which comprises (i) stable absorbance and (ii) absence of UV-induced molecular breakdown, is fundamental. In this study, seven commonly used UV-A, UV-B and broad spectrum UV-AB filters and their combinations, were incorporated into phosphatidylcholine (PC)-based liposomes and exposed to UV-A (275 kJ/m 2). Spectral integrity, evaluated by recording UV-absorbance spectra of the extracted filter molecules and molecular integrity, assessed indirectly via quantification of UV-A induced PC peroxidation, revealed that spectral stability of filter molecules alone or in combination (e.g. trianilino p-carboxyethylhexyl triazine, EHT plus ethylhexyl p-methoxycinnamate, OMC) does not necessarily imply absence of radical generation and that spectral lability does not necessarily have to lead to radical generation and molecular decay (e.g. OMC). This simple system capable of discriminating between essentially photostable and photounstable UV-absorbing molecules alone and in mixtures, might be useful for determining the influence of UV-protection as well as of photostability of UV-absorbers with regard to UV-induced genotoxic/phototoxic and photoageing-related, radical-based processes.

Research paper thumbnail of Nitrogen configuration determined by X-ray analysis on an homogeneous series of 3-Indolinones

Research paper thumbnail of Conformational study on indoline compounds. Structures of 2-phenyl-3-arylimino-3 H -indole 1-Oxide, 1,2-dihydro-2-phenyl-2-benzyl- and 2- tert -Butyl-3-phenylimino-3 H -indole 1-oxyls

J Heterocycl Chem, 1993

ABSTRACT Reacting 1-hydroxy-2-phenylindole with nitrosobenzene, 2-phenyl-3-phenylimino-3H-indole ... more ABSTRACT Reacting 1-hydroxy-2-phenylindole with nitrosobenzene, 2-phenyl-3-phenylimino-3H-indole 1-oxide (1) is produced in only one of the two possible diastereomers. The latter reacts with tert-butylmagnesium chloride and benzylmagnesium chloride giving, after oxidation, the corresponding aminoxyls which show the same configuration of the phenylimino group at C-3 as in 1. This has been demonstrated by means of nmr spectros-copy and X-ray crystal structure and represents an unexpected stereospecific reaction.

Research paper thumbnail of Reactions of indoles with nitrogen monoxide: unexpected formation of azo- bis-indoles from 1,2-disubstituted indoles

Nitric Oxide Biology and Chemistry Official Journal of the Nitric Oxide Society, May 31, 2003

1-Methyl-, 1-ethyl-2-phenylindoles react with nitrogen monoxide, forming mainly 3,3 0-azo-bis-ind... more 1-Methyl-, 1-ethyl-2-phenylindoles react with nitrogen monoxide, forming mainly 3,3 0-azo-bis-indoles, nitrosoindoles together with traces of nitroindoles. 2-Phenylindole, under the same experimental conditions, forms isonitrosoindole in good yields. The formation mechanism of azo-bis-indoles has been demonstrated to occur through 1,2-disubstituted nitrosoindoles by the intermediate formation of a diazonium salt.

Research paper thumbnail of Reactions of N-Nitrosodiphenylamine (II) with Grignard Reagents (I). A Convenient Synthesis of Diaryl and Dialkyl Nitroxyls (III)

Research paper thumbnail of Method for controlled free radical polymerisation or copolymerisation of ethylene under high pressure in the presence of free radical initiators and indoline nitroxide controlling radicals

Research paper thumbnail of Tetrahedron Aminoxyl 1996

Research paper thumbnail of EPR and ENDOR study on mixed crystals of an indolinone nitroxide radical and the isoelectronic ketone. II. EPR and ENDOR investigation on radical pairs in mixed crystals

Http Dx Doi Org 10 1080 00268979100101021, Aug 23, 2006

Research paper thumbnail of Dermatological or cosmetic composition which includes aromatic nitroxide compounds and their use

Research paper thumbnail of 1-Chloroisatin and 2,2-Diphenyl-2,3-dihydro-3-one-1,5,7-trichloroindole: New Oxidants

Syn Commun, 1981

... Corrado Berti and Lucedio Greci Istituto Chimico, Facolta di Ingegneria UniversitL di Bologna... more ... Corrado Berti and Lucedio Greci Istituto Chimico, Facolta di Ingegneria UniversitL di Bologna, Bologna, 40136-ITALY ... The reactions were carried out in ben-zene using equimolar quantities of reagents.Results are summarized in the table. ...

Research paper thumbnail of Homolytic substitution in indolinone nitroxides. IV: Reactions with aminyl radicals. A spectroscopic and crystallographic study

Research paper thumbnail of Antioxidant activity of NADH and its analogue--an in vitro study

Journal of biochemistry and molecular biology, Jan 31, 2004

The antioxidant activities of NADH and of its analogue, 1,4-dihydro-2,6-dimethyl-3,5-dicarbethoxy... more The antioxidant activities of NADH and of its analogue, 1,4-dihydro-2,6-dimethyl-3,5-dicarbethoxy-pyridine (PyH(2)), were evaluated in vitro. NADH was found to be oxidized by the peroxyl radical derived from 2,2-azobis-(2-amidinopropane) dihydrochloride (AAPH) decomposition, in a pH-dependent manner. Both NADH and PyH(2) inhibited the peroxidation of egg yolk lecithin (EYL) liposomes, although PyH(2) was more effective than NADH when 2,2'-azobis-4-methoxy-2,4-dimethyl-valeronitrile (methoxy-AMVN) was employed to induce EYL liposome peroxidation. The antioxidant activities of NADH and PyH(2) were also evaluated by measuring their influences on 1,3-diphenylisobenzofuran (DPBF) fluorescence decay in the presence of peroxyl radicals. NADH and PyH(2) were much more effective at inhibiting DPBF quenching in Triton X-100 micelles than in liposomes. These results indicate that NADH can inhibit lipid peroxidation despite being hydrophilic. Nevertheless, membrane penetration is an importa...

Research paper thumbnail of Synthesis and structural characterization of the first metal complex with an indole nitroxide

Research paper thumbnail of Structure of N-methanesulfonyl-N-phenylhydroxylamine from Fenton's reagent on nitrosobenzene in DMSO

Acta Crystallographica Section C Crystal Structure Communications

independent observed reflections. The SO2 group in the methanesulfonylhydroxylamine moiety adopts... more independent observed reflections. The SO2 group in the methanesulfonylhydroxylamine moiety adopts an orientation such that the N lone-pair bisects the O-SO angle. Significant deviation from coplanarity is observed in the benzene ring.

Research paper thumbnail of Conformational study on 4-(dimethylamino)methanesulfonanilides. 1. Structures of 2-methanesulfonyl- (I), 3-methanesulfonyl- (II) and 2-methanesulfonyl-3-methyl-4-(dimethylamino)methanesulfonanilide (III)

Acta Crystallographica Section C Crystal Structure Communications

Research paper thumbnail of X-ray study of 3-tert-butyl-1-methyl-2-phenylindole, the product of an unexpected tert-butylation reaction

Acta Crystallographica Section C Crystal Structure Communications

A(Cu Ka) = 1"5418/~, /x = 4"6 cm-~, F(000) = 1136, T=293 K, final R=0.052 for 1755 symmetryindepe... more A(Cu Ka) = 1"5418/~, /x = 4"6 cm-~, F(000) = 1136, T=293 K, final R=0.052 for 1755 symmetryindependent observed reflections. The indole nucleus adopts an almost planar conformation with a dihedral angle between the mean planes of the two

Research paper thumbnail of An Unconventional Approach to Photomobile Composite Polymer Films

Advanced materials (Deerfield Beach, Fla.), 2017

Photomobile polymer (Pmp) films are fabricated by using a cheap and fast process. The working mec... more Photomobile polymer (Pmp) films are fabricated by using a cheap and fast process. The working mechanism of the Pmp-film motion under illumination is explained. Details concerning the film structure and formation are given. Two related applications regarding light-induced caterpillar-miming motion and photocontrolled electrical switches are proposed.

Research paper thumbnail of Action of quinolinic and indolinonic aminoxyls as radical-scavenging antioxidants

Chemistry and Physics of Lipids, May 31, 1999

The kinetic studies on the actions of quinolinic and indolinonic aminoxyls in the oxidation of li... more The kinetic studies on the actions of quinolinic and indolinonic aminoxyls in the oxidation of lipid peroxidation induced by free radicals were carried out to evaluate their antioxidant activity. These aminoxyls showed a similar reactivity toward peroxyl radical with a-tocopherol. The antioxidant efficacies of aminoxyls against oxidation of methyl linoleate in homogeneous solution were smaller than that of a-tocopherol. Hydroxylamine, a reduced form of aminoxyl, possessed a comparative antioxidant efficacy with a-tocopherol and was capable of suppressing the consumption of a-tocopherol. Aminoxyls showed more potent antioxidant activity than a-tocopherol against the oxidation of methyl linoleate micelles induced by peroxyl radical or by a combination of copper ion and hydrogen peroxide. These results suggest that quinolinic and indolinonic aminoxyls may act as potent antioxidants against lipid peroxidation, especially in the presence of a good reductant which reduces aminoxyl radicals to hydroxylamines.

Research paper thumbnail of Alkoxyamines of Stable Aromatic Nitroxides: N?Ovs. C?O Bond Homolysis

Helv Chim Acta, 2006

A series of stable 2,2-disubstituted 3-(phenylimino)indol-1-oxyls, the alkoxyamines 3, were prepa... more A series of stable 2,2-disubstituted 3-(phenylimino)indol-1-oxyls, the alkoxyamines 3, were prepared, characterized, and tested as possible candidates in controlled radical polymerization (CRP). The sturctures of 3d and 10 were additionally solved by X-ray diffraction. The lability of the NÀO(C) and (N)OÀC bonds of compounds 3 were compared, and the possibility of NÀO vs. OÀC bond cleavage was evaluated by thermal degradation, ESR spin trapping, MS experiments, and DFT calculations. Alkoxyamines with a primary-or secondary-alkyl group bound to the O-atom of the nitroxide function (hexyl and i-Pr) mainly underwent (undesired) NÀO bond homolysis. When the O-alkyl radical was a tertiary or a benzyl group (crotonyl or styryl), OÀC bond cleavage occurred as the main process, thus suggesting a possible use of these compounds in CRP processes.

Research paper thumbnail of Fenton′s Reagent in Dimethyl Sulfoxide: An Unusual Sulfonylating System. X-Ray Crystallographic Analysis of 4-N,N-Dimethylamino-N,N- dimethanesulfonylaniline

Research paper thumbnail of UV-Filter combinations under UV-A exposure: Concomitant quantification of over-all spectral stability and molecular integrity

Journal of Photochemistry and Photobiology B Biology, May 25, 2007

Efficient UV-absorbing molecules are designed to protect against UV-light over-exposure. However,... more Efficient UV-absorbing molecules are designed to protect against UV-light over-exposure. However, upon UV exposure they may change spectral performance or act as photooxidants via generation of free radicals and reactive oxygen species alone or in combination with others. Therefore, information about their photointegrity which comprises (i) stable absorbance and (ii) absence of UV-induced molecular breakdown, is fundamental. In this study, seven commonly used UV-A, UV-B and broad spectrum UV-AB filters and their combinations, were incorporated into phosphatidylcholine (PC)-based liposomes and exposed to UV-A (275 kJ/m 2). Spectral integrity, evaluated by recording UV-absorbance spectra of the extracted filter molecules and molecular integrity, assessed indirectly via quantification of UV-A induced PC peroxidation, revealed that spectral stability of filter molecules alone or in combination (e.g. trianilino p-carboxyethylhexyl triazine, EHT plus ethylhexyl p-methoxycinnamate, OMC) does not necessarily imply absence of radical generation and that spectral lability does not necessarily have to lead to radical generation and molecular decay (e.g. OMC). This simple system capable of discriminating between essentially photostable and photounstable UV-absorbing molecules alone and in mixtures, might be useful for determining the influence of UV-protection as well as of photostability of UV-absorbers with regard to UV-induced genotoxic/phototoxic and photoageing-related, radical-based processes.

Research paper thumbnail of Nitrogen configuration determined by X-ray analysis on an homogeneous series of 3-Indolinones

Research paper thumbnail of Conformational study on indoline compounds. Structures of 2-phenyl-3-arylimino-3 H -indole 1-Oxide, 1,2-dihydro-2-phenyl-2-benzyl- and 2- tert -Butyl-3-phenylimino-3 H -indole 1-oxyls

J Heterocycl Chem, 1993

ABSTRACT Reacting 1-hydroxy-2-phenylindole with nitrosobenzene, 2-phenyl-3-phenylimino-3H-indole ... more ABSTRACT Reacting 1-hydroxy-2-phenylindole with nitrosobenzene, 2-phenyl-3-phenylimino-3H-indole 1-oxide (1) is produced in only one of the two possible diastereomers. The latter reacts with tert-butylmagnesium chloride and benzylmagnesium chloride giving, after oxidation, the corresponding aminoxyls which show the same configuration of the phenylimino group at C-3 as in 1. This has been demonstrated by means of nmr spectros-copy and X-ray crystal structure and represents an unexpected stereospecific reaction.

Research paper thumbnail of Reactions of indoles with nitrogen monoxide: unexpected formation of azo- bis-indoles from 1,2-disubstituted indoles

Nitric Oxide Biology and Chemistry Official Journal of the Nitric Oxide Society, May 31, 2003

1-Methyl-, 1-ethyl-2-phenylindoles react with nitrogen monoxide, forming mainly 3,3 0-azo-bis-ind... more 1-Methyl-, 1-ethyl-2-phenylindoles react with nitrogen monoxide, forming mainly 3,3 0-azo-bis-indoles, nitrosoindoles together with traces of nitroindoles. 2-Phenylindole, under the same experimental conditions, forms isonitrosoindole in good yields. The formation mechanism of azo-bis-indoles has been demonstrated to occur through 1,2-disubstituted nitrosoindoles by the intermediate formation of a diazonium salt.

Research paper thumbnail of Reactions of N-Nitrosodiphenylamine (II) with Grignard Reagents (I). A Convenient Synthesis of Diaryl and Dialkyl Nitroxyls (III)

Research paper thumbnail of Method for controlled free radical polymerisation or copolymerisation of ethylene under high pressure in the presence of free radical initiators and indoline nitroxide controlling radicals

Research paper thumbnail of Tetrahedron Aminoxyl 1996

Research paper thumbnail of EPR and ENDOR study on mixed crystals of an indolinone nitroxide radical and the isoelectronic ketone. II. EPR and ENDOR investigation on radical pairs in mixed crystals

Http Dx Doi Org 10 1080 00268979100101021, Aug 23, 2006

Research paper thumbnail of Dermatological or cosmetic composition which includes aromatic nitroxide compounds and their use

Research paper thumbnail of 1-Chloroisatin and 2,2-Diphenyl-2,3-dihydro-3-one-1,5,7-trichloroindole: New Oxidants

Syn Commun, 1981

... Corrado Berti and Lucedio Greci Istituto Chimico, Facolta di Ingegneria UniversitL di Bologna... more ... Corrado Berti and Lucedio Greci Istituto Chimico, Facolta di Ingegneria UniversitL di Bologna, Bologna, 40136-ITALY ... The reactions were carried out in ben-zene using equimolar quantities of reagents.Results are summarized in the table. ...

Research paper thumbnail of Homolytic substitution in indolinone nitroxides. IV: Reactions with aminyl radicals. A spectroscopic and crystallographic study