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Papers by Umberto Piarulli

Research paper thumbnail of Effects of a novel cyclic RGD peptidomimetic on cell proliferation, migration and angiogenic activity in human endothelial cells

Cyclic RGD peptidomimetics containing a bifunctional diketopiperazine scaffold are a novel class ... more Cyclic RGD peptidomimetics containing a bifunctional diketopiperazine scaffold are a novel class of high-affinity ligands for the integrins αVβ3 and αVβ5. Since integrins are a promising target for the modulation of normal and pathological angiogenesis, the present study aimed at characterizing the ability of the RGD peptidomimetic cyclo[DKP-RGD] 1 proliferation, migration and network formation in human umbilical vein endothelial cells (HUVEC). Cell viability was assessed by flow cytometry and annexin V (ANX)/propidium iodide (PI) staining. Cell proliferation was evaluated by the ELISA measurement of bromodeoxyuridine (BrdU) incorporation. Network formation by HUVEC cultured in Matrigel-coated plates was evaluated by optical microscopy and image analysis. Integrin subunit mRNA expression was assessed by real time-PCR and Akt phosphorylation by western blot analysis. Cyclo[DKP-RGD] 1 does not affect cell viability and proliferation either in resting conditions or in the presence of the pro-angiogenic growth factors VEGF, EGF, FGF, and IGF-I. Addition of cyclo[DKP-RGD] 1 however significantly decreased network formation induced by pro-angiogenic growth factors or by IL-8. Cyclo[DKP-RGD] 1 did not affect mRNA levels of αV, β3 or β5 integrin subunits, however it significantly reduced the phosphorylation of Akt. Cyclo[DKP-RGD] 1 can be a potential modulator of angiogenesis induced by different growth factors, possibly devoid of the adverse effects of cytotoxic RGD peptidomimetic analogues.

Research paper thumbnail of Highly enantioselective Rh-catalyzed hydrogenations with heterocombinations of pentafluorobenzyl- and methoxybenzyl-derived binaphthyl phosphites

Tetrahedron Letters, 2008

The Rh-catalyzed hydrogenations of dimethyl itaconate and methyl acetamido acrylate using selecte... more The Rh-catalyzed hydrogenations of dimethyl itaconate and methyl acetamido acrylate using selected heterocombinations of pentafluorobenzyl- and methoxybenzyl-derived binaphthyl phosphites proved to be highly enantioselective (ee 93–99%). In these selected cases the Rh-heterocomplexes, which were formed in a statistical amount (ca. 50% by 31P NMR), turned out to be more active and selective than the two homocomplexes.

Research paper thumbnail of A new method for the solution and solid phase synthesis of chiral β-sulfonopeptides under mild conditions

Tetrahedron Letters, 1996

Research paper thumbnail of SolidPhase Synthesis of Peptides Containing Reverse-Turn Mimetic Bicyclic Lactams

European Journal of Organic Chemistry, 1999

Research paper thumbnail of 2-(2-Hydroxyaryl)cinnamic amides: a new class of axially chiral molecules

Tetrahedron, 2006

The syntheses of several differently substituted amides formally derived from a chiral amine, eit... more The syntheses of several differently substituted amides formally derived from a chiral amine, either E-2-(2-hydroxyphenyl)cinnamic acid or both E- and Z-2-(2-hydroxynaphthyl)cinnamic acid, are reported. These molecules display a restricted rotation about the C2–Caryl bond. The barriers to rotation about the C2–Caryl bond were measured by the dynamic 1H NMR and were found to vary between 11.8 and 24.5kcalmol−1, depending on

Research paper thumbnail of ChemInform Abstract: Effect of Ligands and Additives on the Palladium-Promoted Carbonylative Coupling of Vinyl Stannanes and Electron-Poor Enol Triflates

ChemInform, 2001

ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Research paper thumbnail of Copper-Catalyzed, Enantioselective Desymmetrization of meso Cyclic Allylic Bis(diethyl phosphates) with Organozinc Reagents

ChemInform, 2005

ABSTRACT For Abstract see ChemInform Abstract in Full Text.

Research paper thumbnail of Oxo- and imido-molybdenum(VI) and -tungsten(VI) functionalities supported by diacetoneglucose

Journal of the Chemical Society, Dalton Transactions, 1995

ABSTRACT

Research paper thumbnail of Carbohydrate metal complexes as ligands for alkali cations

Journal of the Chemical Society, Chemical Communications, 1994

Research paper thumbnail of Cyclative cleavage via solid-phase supported stabilized sulfur ylides: synthesis of macrocyclic lactones

Tetrahedron Letters, 2002

Research paper thumbnail of ChemInform Abstract: Optimization of New Chiral Ligands for the Copper-Catalyzed Enantioselective Conjugate Addition of Et2Zn to Nitroolefins by High-Throughput Screening of a Parallel Library

Research paper thumbnail of ChemInform Abstract: Discovery of a New Efficient Chiral Ligand for Copper-Catalyzed Enantioselective Michael Additions by High-Throughput Screening of a Parallel Library

Research paper thumbnail of Effects of a novel cyclic RGD peptidomimetic on cell proliferation, migration and angiogenic activity in human endothelial cells

Cyclic RGD peptidomimetics containing a bifunctional diketopiperazine scaffold are a novel class ... more Cyclic RGD peptidomimetics containing a bifunctional diketopiperazine scaffold are a novel class of high-affinity ligands for the integrins αVβ3 and αVβ5. Since integrins are a promising target for the modulation of normal and pathological angiogenesis, the present study aimed at characterizing the ability of the RGD peptidomimetic cyclo[DKP-RGD] 1 proliferation, migration and network formation in human umbilical vein endothelial cells (HUVEC). Cell viability was assessed by flow cytometry and annexin V (ANX)/propidium iodide (PI) staining. Cell proliferation was evaluated by the ELISA measurement of bromodeoxyuridine (BrdU) incorporation. Network formation by HUVEC cultured in Matrigel-coated plates was evaluated by optical microscopy and image analysis. Integrin subunit mRNA expression was assessed by real time-PCR and Akt phosphorylation by western blot analysis. Cyclo[DKP-RGD] 1 does not affect cell viability and proliferation either in resting conditions or in the presence of the pro-angiogenic growth factors VEGF, EGF, FGF, and IGF-I. Addition of cyclo[DKP-RGD] 1 however significantly decreased network formation induced by pro-angiogenic growth factors or by IL-8. Cyclo[DKP-RGD] 1 did not affect mRNA levels of αV, β3 or β5 integrin subunits, however it significantly reduced the phosphorylation of Akt. Cyclo[DKP-RGD] 1 can be a potential modulator of angiogenesis induced by different growth factors, possibly devoid of the adverse effects of cytotoxic RGD peptidomimetic analogues.

Research paper thumbnail of ChemInform Abstract: Enantioselective Rh-Catalyzed Addition of Arylboronic Acids to N-Tosylarylimines

Research paper thumbnail of Combination of Acidic and Basic Phosphites in Rhodium-Induced Hydrogenations

Research paper thumbnail of Chiral (salen)Co(III)(N-benzyl-l-serine)-derived phosphites: monodentate P-ligands for enantioselective catalytic applications

Tetrahedron: Asymmetry, 2009

Chiral (salen)cobalt(II) and cobalt(III) complexes have found wide application in several asymmet... more Chiral (salen)cobalt(II) and cobalt(III) complexes have found wide application in several asymmetric transformations. 1 We have recently reported a novel approach to the resolution of racemic N-benzyl α-amino acids (N-Bn-AA) by liquid–liquid extraction, using the lipophilic chiral ( ...

Research paper thumbnail of A carbonylative cross-coupling strategy to the total synthesis of the sarcodictyins: preliminary studies and synthesis of a cyclization precursor

Tetrahedron Letters, 2001

Research paper thumbnail of Ureas: New efficient Lewis base catalysts for the allylation of aldehydes

Tetrahedron Letters, 1999

Research paper thumbnail of Rh-catalysed asymmetric hydrogenations with a dynamic library of chiral tropos phosphorus-ligands

Tetrahedron Letters, 2004

Research paper thumbnail of Foldamers of bifunctional diketopiperazines displaying a β-bend ribbon structure

Tetrahedron Letters, 2010

The synthesis of two oligomers, of a bifunctional diketopiperazine scaffold DKP-1, formally deriv... more The synthesis of two oligomers, of a bifunctional diketopiperazine scaffold DKP-1, formally derived from the cyclization of l-aspartic acid and (S)-2,3-diaminopropionic acid, is reported. A trimeric and a tetrameric structure were prepared by solution-phase peptide synthesis (Boc strategy). Conformational analysis of these derivatives was carried out by a combination of 1H NMR spectroscopy, CD spectroscopy, and molecular modeling, and revealed the formation of β-bend ribbon involving 10-membered H-bonded rings and a reverse turn of the growing peptide chain.

Research paper thumbnail of Effects of a novel cyclic RGD peptidomimetic on cell proliferation, migration and angiogenic activity in human endothelial cells

Cyclic RGD peptidomimetics containing a bifunctional diketopiperazine scaffold are a novel class ... more Cyclic RGD peptidomimetics containing a bifunctional diketopiperazine scaffold are a novel class of high-affinity ligands for the integrins αVβ3 and αVβ5. Since integrins are a promising target for the modulation of normal and pathological angiogenesis, the present study aimed at characterizing the ability of the RGD peptidomimetic cyclo[DKP-RGD] 1 proliferation, migration and network formation in human umbilical vein endothelial cells (HUVEC). Cell viability was assessed by flow cytometry and annexin V (ANX)/propidium iodide (PI) staining. Cell proliferation was evaluated by the ELISA measurement of bromodeoxyuridine (BrdU) incorporation. Network formation by HUVEC cultured in Matrigel-coated plates was evaluated by optical microscopy and image analysis. Integrin subunit mRNA expression was assessed by real time-PCR and Akt phosphorylation by western blot analysis. Cyclo[DKP-RGD] 1 does not affect cell viability and proliferation either in resting conditions or in the presence of the pro-angiogenic growth factors VEGF, EGF, FGF, and IGF-I. Addition of cyclo[DKP-RGD] 1 however significantly decreased network formation induced by pro-angiogenic growth factors or by IL-8. Cyclo[DKP-RGD] 1 did not affect mRNA levels of αV, β3 or β5 integrin subunits, however it significantly reduced the phosphorylation of Akt. Cyclo[DKP-RGD] 1 can be a potential modulator of angiogenesis induced by different growth factors, possibly devoid of the adverse effects of cytotoxic RGD peptidomimetic analogues.

Research paper thumbnail of Highly enantioselective Rh-catalyzed hydrogenations with heterocombinations of pentafluorobenzyl- and methoxybenzyl-derived binaphthyl phosphites

Tetrahedron Letters, 2008

The Rh-catalyzed hydrogenations of dimethyl itaconate and methyl acetamido acrylate using selecte... more The Rh-catalyzed hydrogenations of dimethyl itaconate and methyl acetamido acrylate using selected heterocombinations of pentafluorobenzyl- and methoxybenzyl-derived binaphthyl phosphites proved to be highly enantioselective (ee 93–99%). In these selected cases the Rh-heterocomplexes, which were formed in a statistical amount (ca. 50% by 31P NMR), turned out to be more active and selective than the two homocomplexes.

Research paper thumbnail of A new method for the solution and solid phase synthesis of chiral β-sulfonopeptides under mild conditions

Tetrahedron Letters, 1996

Research paper thumbnail of SolidPhase Synthesis of Peptides Containing Reverse-Turn Mimetic Bicyclic Lactams

European Journal of Organic Chemistry, 1999

Research paper thumbnail of 2-(2-Hydroxyaryl)cinnamic amides: a new class of axially chiral molecules

Tetrahedron, 2006

The syntheses of several differently substituted amides formally derived from a chiral amine, eit... more The syntheses of several differently substituted amides formally derived from a chiral amine, either E-2-(2-hydroxyphenyl)cinnamic acid or both E- and Z-2-(2-hydroxynaphthyl)cinnamic acid, are reported. These molecules display a restricted rotation about the C2–Caryl bond. The barriers to rotation about the C2–Caryl bond were measured by the dynamic 1H NMR and were found to vary between 11.8 and 24.5kcalmol−1, depending on

Research paper thumbnail of ChemInform Abstract: Effect of Ligands and Additives on the Palladium-Promoted Carbonylative Coupling of Vinyl Stannanes and Electron-Poor Enol Triflates

ChemInform, 2001

ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Research paper thumbnail of Copper-Catalyzed, Enantioselective Desymmetrization of meso Cyclic Allylic Bis(diethyl phosphates) with Organozinc Reagents

ChemInform, 2005

ABSTRACT For Abstract see ChemInform Abstract in Full Text.

Research paper thumbnail of Oxo- and imido-molybdenum(VI) and -tungsten(VI) functionalities supported by diacetoneglucose

Journal of the Chemical Society, Dalton Transactions, 1995

ABSTRACT

Research paper thumbnail of Carbohydrate metal complexes as ligands for alkali cations

Journal of the Chemical Society, Chemical Communications, 1994

Research paper thumbnail of Cyclative cleavage via solid-phase supported stabilized sulfur ylides: synthesis of macrocyclic lactones

Tetrahedron Letters, 2002

Research paper thumbnail of ChemInform Abstract: Optimization of New Chiral Ligands for the Copper-Catalyzed Enantioselective Conjugate Addition of Et2Zn to Nitroolefins by High-Throughput Screening of a Parallel Library

Research paper thumbnail of ChemInform Abstract: Discovery of a New Efficient Chiral Ligand for Copper-Catalyzed Enantioselective Michael Additions by High-Throughput Screening of a Parallel Library

Research paper thumbnail of Effects of a novel cyclic RGD peptidomimetic on cell proliferation, migration and angiogenic activity in human endothelial cells

Cyclic RGD peptidomimetics containing a bifunctional diketopiperazine scaffold are a novel class ... more Cyclic RGD peptidomimetics containing a bifunctional diketopiperazine scaffold are a novel class of high-affinity ligands for the integrins αVβ3 and αVβ5. Since integrins are a promising target for the modulation of normal and pathological angiogenesis, the present study aimed at characterizing the ability of the RGD peptidomimetic cyclo[DKP-RGD] 1 proliferation, migration and network formation in human umbilical vein endothelial cells (HUVEC). Cell viability was assessed by flow cytometry and annexin V (ANX)/propidium iodide (PI) staining. Cell proliferation was evaluated by the ELISA measurement of bromodeoxyuridine (BrdU) incorporation. Network formation by HUVEC cultured in Matrigel-coated plates was evaluated by optical microscopy and image analysis. Integrin subunit mRNA expression was assessed by real time-PCR and Akt phosphorylation by western blot analysis. Cyclo[DKP-RGD] 1 does not affect cell viability and proliferation either in resting conditions or in the presence of the pro-angiogenic growth factors VEGF, EGF, FGF, and IGF-I. Addition of cyclo[DKP-RGD] 1 however significantly decreased network formation induced by pro-angiogenic growth factors or by IL-8. Cyclo[DKP-RGD] 1 did not affect mRNA levels of αV, β3 or β5 integrin subunits, however it significantly reduced the phosphorylation of Akt. Cyclo[DKP-RGD] 1 can be a potential modulator of angiogenesis induced by different growth factors, possibly devoid of the adverse effects of cytotoxic RGD peptidomimetic analogues.

Research paper thumbnail of ChemInform Abstract: Enantioselective Rh-Catalyzed Addition of Arylboronic Acids to N-Tosylarylimines

Research paper thumbnail of Combination of Acidic and Basic Phosphites in Rhodium-Induced Hydrogenations

Research paper thumbnail of Chiral (salen)Co(III)(N-benzyl-l-serine)-derived phosphites: monodentate P-ligands for enantioselective catalytic applications

Tetrahedron: Asymmetry, 2009

Chiral (salen)cobalt(II) and cobalt(III) complexes have found wide application in several asymmet... more Chiral (salen)cobalt(II) and cobalt(III) complexes have found wide application in several asymmetric transformations. 1 We have recently reported a novel approach to the resolution of racemic N-benzyl α-amino acids (N-Bn-AA) by liquid–liquid extraction, using the lipophilic chiral ( ...

Research paper thumbnail of A carbonylative cross-coupling strategy to the total synthesis of the sarcodictyins: preliminary studies and synthesis of a cyclization precursor

Tetrahedron Letters, 2001

Research paper thumbnail of Ureas: New efficient Lewis base catalysts for the allylation of aldehydes

Tetrahedron Letters, 1999

Research paper thumbnail of Rh-catalysed asymmetric hydrogenations with a dynamic library of chiral tropos phosphorus-ligands

Tetrahedron Letters, 2004

Research paper thumbnail of Foldamers of bifunctional diketopiperazines displaying a β-bend ribbon structure

Tetrahedron Letters, 2010

The synthesis of two oligomers, of a bifunctional diketopiperazine scaffold DKP-1, formally deriv... more The synthesis of two oligomers, of a bifunctional diketopiperazine scaffold DKP-1, formally derived from the cyclization of l-aspartic acid and (S)-2,3-diaminopropionic acid, is reported. A trimeric and a tetrameric structure were prepared by solution-phase peptide synthesis (Boc strategy). Conformational analysis of these derivatives was carried out by a combination of 1H NMR spectroscopy, CD spectroscopy, and molecular modeling, and revealed the formation of β-bend ribbon involving 10-membered H-bonded rings and a reverse turn of the growing peptide chain.