Ugo Chiacchio - Academia.edu (original) (raw)
Papers by Ugo Chiacchio
Background Alzhèimer Disease (AD) is characterized by intracellular and extracellular protein agg... more Background Alzhèimer Disease (AD) is characterized by intracellular and extracellular protein aggregates in the brain, including amyloid-beta (Aβ). Aβ is a substrate for tissue transglutaminase (TG2), an ubiquitarian calcium-dependent protein that induces Aβ oligomerization and aggregation. We assessed the effect of full native peptide of Aβ(1–42), the fragments (25–35 and 35–25) on TG2 expression levels and its isoforms (Long and Short) on Olfactory Ensheathing Cells (OECs). The levels of cytoskeletal proteins, Vimentin and Glial Fibrillary Acid Protein (GFAP), were also studied. The effect of the pre-treatment with Indicaxanthin on cell viability, total Reactive Oxygen Species (ROS), superoxide anion (O2−) and apoptotic pathway activation was assessed. Since Nestin is co-expressed in pluripotent stem cells with cyclin D1, their levels were evaluated. Methods Mouse primary OECs were exposed to 10 µM Aβ(1–42) or Aβ(25–35) or Aβ(35–25) for 24 h both in the absence and in the presence...
![Research paper thumbnail of A new microwave-assisted thionation-heterocyclization process leading to benzo[c]thiophene-1(3H)-thione and 1H-isothiochromene-1-thione derivatives](https://attachments.academia-assets.com/110706418/thumbnails/1.jpg)
](RSC Advances, 2016
The first example of a MW-assisted tandem thionation/S-cyclization process, leading to benzothiop... more The first example of a MW-assisted tandem thionation/S-cyclization process, leading to benzothiophenethione and isothiochromenethione derivatives, is reported.
The Activation of Dioxygen and Homogeneous Catalytic Oxidation, 1993
The chemistry of oxidation of Mo(VI) and W(VI) peroxopolyoxo complexes is becoming of increasing ... more The chemistry of oxidation of Mo(VI) and W(VI) peroxopolyoxo complexes is becoming of increasing interest in the field or oxygen transfer processes. Alkenes, alkynes, alcohols, diols, sulfides, solfoxides undergo easy oxidation by these reagents both under stoichiometric and catalytic conditions.1
ChemInform, 2011
Review: 441 refs.
Journal of the Chemical Society, Perkin Transactions 2, 2000
ABSTRACT
Tetrahedron Letters, 2002
Unprotected pyrimidine bases were used in Mitsunobu reaction to afford in high yield new substitu... more Unprotected pyrimidine bases were used in Mitsunobu reaction to afford in high yield new substituted pyrrolidines. The reaction is chemo-, regio-and stereoselective affording exclusively N-1 alkylated derivatives of (3S)-N-benzyl-3-hydroxypyrrolidine and (3S, 4S)-N-benzyl-3, 4-dihydroxypyrrolidine.
Merino/Chemical Synthesis of Nucleoside Analogues, 2013
ABSTRACT This chapter covers all the synthetic efforts in the construction of nucleoside analogue... more ABSTRACT This chapter covers all the synthetic efforts in the construction of nucleoside analogues in which the furanose ring is replaced by an alternative heterocyclic system. In this chapter the isoxazolidine nucleosides have been classified depending on the substituents present on the pentatomic ring. Comprehensive literature searches reveal that compounds belonging to classes I to V have been prepared. The first synthetic approach to compounds of 4′-AZA-2′,3′-dideoxynucleosides I were reported in 1992. An efficient synthesis of 3-aryl-substituted derivatives in good yields and short reaction times has been reported. C-Nucleosides have been synthesized according to the 1,3-dipolar cycloaddition methodology. According to the statement that antiviral activity of modified nucleosides is strictly related to their conversion to the triphosphate form, phosphonated N,O nucleosides have been synthesized. Natural psicofuranosyl nucleosides are endowed with interesting biological activities. Different synthetic approaches toward 1′-homo-C- and N-nucleosides have been reported in the literature.
Topics in Medicinal Chemistry, 2013
Tetrahedron, 2006
The enantioselective synthesis of homocarbocyclic-2 0 oxo-3 0-azanucleosides has been performed b... more The enantioselective synthesis of homocarbocyclic-2 0 oxo-3 0-azanucleosides has been performed by cycloaddition reaction of the N-glycosyl nitrones with allyl nucleobases. The use of nitrones originated from two different carbohydrates, the N-ribosyl nitrone and the Nmannosyl nitrone, proceeded in a stereocontrolled and predictable manner with a good degree of enantioselectivity, so allowing an easy entry to both enantiomers.
Tetrahedron: Asymmetry, 2005
An efficient synthetic route to isoxazolidinyl analogues of tiazofurin has been developed. The st... more An efficient synthetic route to isoxazolidinyl analogues of tiazofurin has been developed. The strategy involves, as a key step, a 1,3-dipolar cycloaddition between acrylonitrile and chiral nonracemic nitrones. An opposite diastereofacial induction was observed when the chiral group was placed at either the carbon atom or the nitrogen one of the nitrone function. The 2-cyano isoxazolidines obtained were further converted into the enantiomeric target compounds by constructing the thiazole ring via condensation with L L-cysteine.
Tetrahedron: Asymmetry, 2002
Starting from L-aminoacids, 5-N-unsubstituted isothiazolo[4,5-c]isoxazole 4,4-dioxides have been ... more Starting from L-aminoacids, 5-N-unsubstituted isothiazolo[4,5-c]isoxazole 4,4-dioxides have been synthesized and used as chiral auxiliaries in asymmetric conjugated additions of Grignard reagents to a,b-unsaturated carboxylic acids.
Tetrahedron, 2003
The synthesis of two new bicyclic nucleoside analogues is reported. These compounds are iso-homon... more The synthesis of two new bicyclic nucleoside analogues is reported. These compounds are iso-homonucleoside and are synthesised through a 1,3-dipolar cycloaddition of an enantiopure cyclic nitrone to protected allyl acohol and subsequent introduction of thymine by a Mitsunobu reaction.
The Journal of Organic Chemistry
A new rearrangement pattern of the 4-isoxazoline system is reported. The reaction, starting from ... more A new rearrangement pattern of the 4-isoxazoline system is reported. The reaction, starting from 3,3disubstituted derivatives and leading to R,-unsaturated amides, proceeds through the quaternarization of the nitrogen atom and involves the heterolytic cleavage of C 3-N bond, assisted by the formation of a relatively stable intermediate. The overall process represents a useful conversion of ketones into R,-unsaturated amides.
The Journal of Organic Chemistry, 2013
A new method for the preparation of highly functionalized βenamino diones has been developed. The... more A new method for the preparation of highly functionalized βenamino diones has been developed. The protocol involves an initial selfcatalyzed Mannich-type reaction of enolizable cyclic 1,3-dicarbonyls to nitrones, followed by a spontaneous intramolecular reorganization of the resulting nonisolated hydroxylamine to enamino derivatives. These compounds retain the features of unnatural α-amino acids. The ease of preparation makes them attractive intermediates for the synthesis of peptidomimetics, polyheterocycles, and other multifunctional compounds. All experimental results have been efficiently rationalized by in silico studies at the M06-2X level of theory, and a valid mechanistic pathway has been proposed.
HETEROCYCLES, 1993
ABSTRACT
HETEROCYCLES, 1997
ABSTRACT
HETEROCYCLES, 1998
ABSTRACT
European Journal of Organic Chemistry, 2002
A flexible synthetic procedure to access a new and biologically interesting class of N,O-psiconuc... more A flexible synthetic procedure to access a new and biologically interesting class of N,O-psiconucleosides by 1,3-dipolar cycloaddition of C-ethoxycarbonyl-N-methyl nitrone with ethyl 2-(acetyloxy)acrylate, followed by Vö rbruggen nucleosidation and sodium borohydride reduction, is described.
Bioorganic & Medicinal Chemistry, 2004
The synthesis of 4&am... more The synthesis of 4'-alpha-C-branched N,O-nucleosides has been described, based on the 1,3-dipolar cycloaddition of nitrones with vinyl acetate followed by coupling with silylated nucleobases, The obtained compounds have been evaluated for their activity against HSV-1, HSV-2, HTLV-1. Cytotoxicity and apoptotic activity have been also investigated: compound 10c shows moderate apoptotic activity in Molt-3 cells.
Tetrahedron, 2004
A new class of homo-N, O-nucleosides has been designed, based on the 1, 3-dipolar cycloaddition o... more A new class of homo-N, O-nucleosides has been designed, based on the 1, 3-dipolar cycloaddition of C-substituted nitrones with allyl nucleobases. The N-methyl-C-ethoxycarbonyl nitrone, and the C-α-silyloxymethyl-N-methyl nitrone have been exploited: ...
Background Alzhèimer Disease (AD) is characterized by intracellular and extracellular protein agg... more Background Alzhèimer Disease (AD) is characterized by intracellular and extracellular protein aggregates in the brain, including amyloid-beta (Aβ). Aβ is a substrate for tissue transglutaminase (TG2), an ubiquitarian calcium-dependent protein that induces Aβ oligomerization and aggregation. We assessed the effect of full native peptide of Aβ(1–42), the fragments (25–35 and 35–25) on TG2 expression levels and its isoforms (Long and Short) on Olfactory Ensheathing Cells (OECs). The levels of cytoskeletal proteins, Vimentin and Glial Fibrillary Acid Protein (GFAP), were also studied. The effect of the pre-treatment with Indicaxanthin on cell viability, total Reactive Oxygen Species (ROS), superoxide anion (O2−) and apoptotic pathway activation was assessed. Since Nestin is co-expressed in pluripotent stem cells with cyclin D1, their levels were evaluated. Methods Mouse primary OECs were exposed to 10 µM Aβ(1–42) or Aβ(25–35) or Aβ(35–25) for 24 h both in the absence and in the presence...
RSC Advances, 2016
The first example of a MW-assisted tandem thionation/S-cyclization process, leading to benzothiop... more The first example of a MW-assisted tandem thionation/S-cyclization process, leading to benzothiophenethione and isothiochromenethione derivatives, is reported.
The Activation of Dioxygen and Homogeneous Catalytic Oxidation, 1993
The chemistry of oxidation of Mo(VI) and W(VI) peroxopolyoxo complexes is becoming of increasing ... more The chemistry of oxidation of Mo(VI) and W(VI) peroxopolyoxo complexes is becoming of increasing interest in the field or oxygen transfer processes. Alkenes, alkynes, alcohols, diols, sulfides, solfoxides undergo easy oxidation by these reagents both under stoichiometric and catalytic conditions.1
ChemInform, 2011
Review: 441 refs.
Journal of the Chemical Society, Perkin Transactions 2, 2000
ABSTRACT
Tetrahedron Letters, 2002
Unprotected pyrimidine bases were used in Mitsunobu reaction to afford in high yield new substitu... more Unprotected pyrimidine bases were used in Mitsunobu reaction to afford in high yield new substituted pyrrolidines. The reaction is chemo-, regio-and stereoselective affording exclusively N-1 alkylated derivatives of (3S)-N-benzyl-3-hydroxypyrrolidine and (3S, 4S)-N-benzyl-3, 4-dihydroxypyrrolidine.
Merino/Chemical Synthesis of Nucleoside Analogues, 2013
ABSTRACT This chapter covers all the synthetic efforts in the construction of nucleoside analogue... more ABSTRACT This chapter covers all the synthetic efforts in the construction of nucleoside analogues in which the furanose ring is replaced by an alternative heterocyclic system. In this chapter the isoxazolidine nucleosides have been classified depending on the substituents present on the pentatomic ring. Comprehensive literature searches reveal that compounds belonging to classes I to V have been prepared. The first synthetic approach to compounds of 4′-AZA-2′,3′-dideoxynucleosides I were reported in 1992. An efficient synthesis of 3-aryl-substituted derivatives in good yields and short reaction times has been reported. C-Nucleosides have been synthesized according to the 1,3-dipolar cycloaddition methodology. According to the statement that antiviral activity of modified nucleosides is strictly related to their conversion to the triphosphate form, phosphonated N,O nucleosides have been synthesized. Natural psicofuranosyl nucleosides are endowed with interesting biological activities. Different synthetic approaches toward 1′-homo-C- and N-nucleosides have been reported in the literature.
Topics in Medicinal Chemistry, 2013
Tetrahedron, 2006
The enantioselective synthesis of homocarbocyclic-2 0 oxo-3 0-azanucleosides has been performed b... more The enantioselective synthesis of homocarbocyclic-2 0 oxo-3 0-azanucleosides has been performed by cycloaddition reaction of the N-glycosyl nitrones with allyl nucleobases. The use of nitrones originated from two different carbohydrates, the N-ribosyl nitrone and the Nmannosyl nitrone, proceeded in a stereocontrolled and predictable manner with a good degree of enantioselectivity, so allowing an easy entry to both enantiomers.
Tetrahedron: Asymmetry, 2005
An efficient synthetic route to isoxazolidinyl analogues of tiazofurin has been developed. The st... more An efficient synthetic route to isoxazolidinyl analogues of tiazofurin has been developed. The strategy involves, as a key step, a 1,3-dipolar cycloaddition between acrylonitrile and chiral nonracemic nitrones. An opposite diastereofacial induction was observed when the chiral group was placed at either the carbon atom or the nitrogen one of the nitrone function. The 2-cyano isoxazolidines obtained were further converted into the enantiomeric target compounds by constructing the thiazole ring via condensation with L L-cysteine.
Tetrahedron: Asymmetry, 2002
Starting from L-aminoacids, 5-N-unsubstituted isothiazolo[4,5-c]isoxazole 4,4-dioxides have been ... more Starting from L-aminoacids, 5-N-unsubstituted isothiazolo[4,5-c]isoxazole 4,4-dioxides have been synthesized and used as chiral auxiliaries in asymmetric conjugated additions of Grignard reagents to a,b-unsaturated carboxylic acids.
Tetrahedron, 2003
The synthesis of two new bicyclic nucleoside analogues is reported. These compounds are iso-homon... more The synthesis of two new bicyclic nucleoside analogues is reported. These compounds are iso-homonucleoside and are synthesised through a 1,3-dipolar cycloaddition of an enantiopure cyclic nitrone to protected allyl acohol and subsequent introduction of thymine by a Mitsunobu reaction.
The Journal of Organic Chemistry
A new rearrangement pattern of the 4-isoxazoline system is reported. The reaction, starting from ... more A new rearrangement pattern of the 4-isoxazoline system is reported. The reaction, starting from 3,3disubstituted derivatives and leading to R,-unsaturated amides, proceeds through the quaternarization of the nitrogen atom and involves the heterolytic cleavage of C 3-N bond, assisted by the formation of a relatively stable intermediate. The overall process represents a useful conversion of ketones into R,-unsaturated amides.
The Journal of Organic Chemistry, 2013
A new method for the preparation of highly functionalized βenamino diones has been developed. The... more A new method for the preparation of highly functionalized βenamino diones has been developed. The protocol involves an initial selfcatalyzed Mannich-type reaction of enolizable cyclic 1,3-dicarbonyls to nitrones, followed by a spontaneous intramolecular reorganization of the resulting nonisolated hydroxylamine to enamino derivatives. These compounds retain the features of unnatural α-amino acids. The ease of preparation makes them attractive intermediates for the synthesis of peptidomimetics, polyheterocycles, and other multifunctional compounds. All experimental results have been efficiently rationalized by in silico studies at the M06-2X level of theory, and a valid mechanistic pathway has been proposed.
HETEROCYCLES, 1993
ABSTRACT
HETEROCYCLES, 1997
ABSTRACT
HETEROCYCLES, 1998
ABSTRACT
European Journal of Organic Chemistry, 2002
A flexible synthetic procedure to access a new and biologically interesting class of N,O-psiconuc... more A flexible synthetic procedure to access a new and biologically interesting class of N,O-psiconucleosides by 1,3-dipolar cycloaddition of C-ethoxycarbonyl-N-methyl nitrone with ethyl 2-(acetyloxy)acrylate, followed by Vö rbruggen nucleosidation and sodium borohydride reduction, is described.
Bioorganic & Medicinal Chemistry, 2004
The synthesis of 4&am... more The synthesis of 4'-alpha-C-branched N,O-nucleosides has been described, based on the 1,3-dipolar cycloaddition of nitrones with vinyl acetate followed by coupling with silylated nucleobases, The obtained compounds have been evaluated for their activity against HSV-1, HSV-2, HTLV-1. Cytotoxicity and apoptotic activity have been also investigated: compound 10c shows moderate apoptotic activity in Molt-3 cells.
Tetrahedron, 2004
A new class of homo-N, O-nucleosides has been designed, based on the 1, 3-dipolar cycloaddition o... more A new class of homo-N, O-nucleosides has been designed, based on the 1, 3-dipolar cycloaddition of C-substituted nitrones with allyl nucleobases. The N-methyl-C-ethoxycarbonyl nitrone, and the C-α-silyloxymethyl-N-methyl nitrone have been exploited: ...