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Papers by Thomas Giannopoulos

Research paper thumbnail of Tele vs. Oxidative Substitution of Hydrogen inmeta Monochloromethyl, Dichloromethyl, and Trichloromethyl Nitrobenzenes in the Reaction with Grignard Reagents

European Journal of Organic Chemistry, 2003

ABSTRACT Grignard reagents add to nitrobenzene derivatives containing trichloromethyl, dichlorome... more ABSTRACT Grignard reagents add to nitrobenzene derivatives containing trichloromethyl, dichloromethyl, and monochloromethyl groups in the meta position to form σH adducts, which are either further converted through departure of a chloride anion, giving products of tele substitution, or oxidized to products of oxidative nucleophilic substitution of hydrogen. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Research paper thumbnail of Abnormal Nucleophilic Substitution in 3-Trichloromethylpyridine, its N-Oxide and 3,5-Bis(trichloromethyl)pyridine

Tetrahedron, Nov 1, 1995

The scope of abnormal reactions of nucleophiles with β-trichloromethylazines is further explored:... more The scope of abnormal reactions of nucleophiles with β-trichloromethylazines is further explored: reactions of 3-trichloromethylpyridine with nucleophiles other than methoxide, and reactions of 3-trichloromethylpyridine N-oxide and 3,5-bis(trichloromethyl)pyridine with methoxide. Attack at a ring carbon, followed by hydrogen migration to the side-chain, occurred in most cases, though attack at the trichloromethyl carbon was also sometimes observed.We now report further studies on

Research paper thumbnail of Determination of plasma, urine, and bovine serum albumin low-molecular-weight carbonyl levels by capillary gas chromatography with electron-capture and mass-selective detection

Analytical Biochemistry, 2005

Peroxidation of lipids produces low-molecular-weight carbonyl compounds, which are reactive with ... more Peroxidation of lipids produces low-molecular-weight carbonyl compounds, which are reactive with biological nucleophiles. The analysis of these compounds is often diYcult. A multicomponent method for the determination of 11 of them in biological samples is reported. The samples are subjected to a pretreatment-derivatization procedure followed by gas chromatographic analysis with either electron-capture detection (ECD) or mass-selective detection (MSD) in the selected-ion monitoring mode. The procedure involves derivatization of the analyte with 2,4,6-trichlorophenylhydrazine, extraction with n-hexane, and separation of the derivatization products on a nonpolar gas chromatographic column. The concentration of the derivatization reagent, pH, reaction time, temperature, and presence of extraneous ions were investigated to determine the optimal derivatization conditions. Under these conditions, the method allows for the selective detection of low-molecular-weight carbonyl compounds at femtomole levels in several biological materials such as plasma, urine, and bovine serum albumin without interferences. The limits of detection were in the ranges 0.01-0.2 M for ECD and 0.15-1.5 M for MSD. The mean procedural recoveries obtained during the method validation were within the range 85-95% and the intra-and interassay standard deviations do not exceed 4.6 and 6.1%, respectively.

Research paper thumbnail of ChemInform Abstract: Synthesis, Chemistry, and Biological Properties of Thienopyrimidines

Research paper thumbnail of ChemInform Abstract: Abnormal Nucleophilic Substitution in 3-Trichloromethylpyridine, Its N- Oxide and 3,5Bis(trichloromethyl)pyridine

Research paper thumbnail of ChemInform Abstract: Synthesis of Some β-Trichloromethylazines and -diazines

Cheminform, 2010

Synthesis of Some β-Trichloromethylazines and -diazines.

Research paper thumbnail of Synthesis of some ?-trichloromethyl-azines and -diazines

Journal of The Chemical Society-perkin Transactions 1, 1995

ABSTRACT Syntheses of compounds required as substrates for reactions with nucleophiles are report... more ABSTRACT Syntheses of compounds required as substrates for reactions with nucleophiles are reported: 2-trichloromethylquinoxaline 5, 3-trichloromethylquinoline 6, 3,5-bis(trichloromethyl)pyridine 7, 2,5-bis(trichloromethyl)pyrazine 8 and 5-trichloromethylpyrimidine 9.

Research paper thumbnail of Abnormal Nucleophilic Substitution in 3-Trichloromethylpyridine, its N-Oxide and 3,5Bis(trichloromethyl)pyridine

Tetrahedron, 1995

The scope of abnormal reactions of nucleophiles with β-trichloromethylazines is further explored:... more The scope of abnormal reactions of nucleophiles with β-trichloromethylazines is further explored: reactions of 3-trichloromethylpyridine with nucleophiles other than methoxide, and reactions of 3-trichloromethylpyridine N-oxide and 3,5-bis(trichloromethyl)pyridine with methoxide. Attack at a ring carbon, followed by hydrogen migration to the side-chain, occurred in most cases, though attack at the trichloromethyl carbon was also sometimes observed.We now report further studies on

Research paper thumbnail of ChemInform Abstract: Tele Nucleophilic Aromatic Substitutions in 1-Nitro-3- and 1,3-Dinitro-5-trichloromethylbenzene, and 3-Trichloromethylbenzonitrile. A New Synthesis of the 1,4-Benzothiazine-3(4H)-one Ring System from 3-Nitrobenzoic Acid

Research paper thumbnail of Tele Nucleophilic Aromatic Substitutions in 1Nitro3- and 1,3-Dinitro-5-trichloromethylbenzene, and 3-Trichloromethylbenzonitrile. A New Synthesis of the 1,4-Benzothiazine-3(4 H)-one Ring System from 3-Nitrobenzoic Acid

Tetrahedron, 2000

3-Trichloromethylnitrobenzene 2, 1,3-dinitro-5-trichloromethylbenzene 13 and 3-trichloromethylben... more 3-Trichloromethylnitrobenzene 2, 1,3-dinitro-5-trichloromethylbenzene 13 and 3-trichloromethylbenzonitrile 18 react with sodium methoxide to give 4-methoxy-3-nitrobenzaldehyde 6, 4-methoxy-3,5-dinitrobenzaldehyde 15 and 5-dimethoxymethyl-2-methoxybenzonitrile 19, respectively. Compounds 2 and 13 react with methyl thioglycolate to afford dichloromethylacetates 7 and 16, respectively. These products are the result of tele nucleophilic aromatic substitution. Compound 18 reacted with methyl thioglycolate to give acetate 20 resulting from nucleophilic displacement

Research paper thumbnail of Synthesis, Chemistry, and Biological Properties of Thienopyrimidines

Advances in Heterocyclic Chemistry, 1996

Research paper thumbnail of Physicochemical study of novel organoclays as heavy metal ion adsorbents for environmental remediation

Journal of Colloid and Interface Science, 2007

Four organic-modified clays based on a SWy-2 montmorillonite were prepared by embedding ammonium ... more Four organic-modified clays based on a SWy-2 montmorillonite were prepared by embedding ammonium organic derivatives with different chelating functionalities (-NH 2 , -COOH, -SH or -CS 2 ) in the interlayer space of montmorillonite. Organic molecules such as (a) hexamethylenediamine, (b) 2-(dimethylamino)ethenethiol, (c) 5-aminovaleric acid and (d) hexamethylenediamine-dithiocarbamate were used for the clay modification in order to study the effect of the chelating functionality on heavy metal ions binding from aqueous solutions. The organoclays were characterized by powder X-ray diffraction (XRD), infrared (FTIR) and NMR spectroscopies. The experimental data showed that the organic molecules are intercalated into the interlamelar space with the long dimension parallel to the clay sheets. Their sorbing properties were evaluated for the removal of heavy metals, Pb, Cd and Zn, from aqueous solutions as a function of the pH. When compared with the unmodified SWy-2 montmorillonite, the modified clays show significant improvement in terms of sorbing selectivity as well as of metal loading capacity. The fit to adsorption data by a Surface Complexation Model shows that the intercalated molecules act as specific binding sites in the clay. These contribute additional sorption capacity which is additive to the variable charge edge-sites of the clay in competition with the permanent charge sites. (Y. Deligiannakis). heavy metals. Moreover, due to their abundance in soil systems, their high specific surface area and exchange capacity, clay minerals such as montmorillonite play a significant role in determining the availability and transport of metals species in soil and sediments .

Research paper thumbnail of Tele vs. Oxidative Substitution of Hydrogen inmeta Monochloromethyl, Dichloromethyl, and Trichloromethyl Nitrobenzenes in the Reaction with Grignard Reagents

European Journal of Organic Chemistry, 2003

ABSTRACT Grignard reagents add to nitrobenzene derivatives containing trichloromethyl, dichlorome... more ABSTRACT Grignard reagents add to nitrobenzene derivatives containing trichloromethyl, dichloromethyl, and monochloromethyl groups in the meta position to form σH adducts, which are either further converted through departure of a chloride anion, giving products of tele substitution, or oxidized to products of oxidative nucleophilic substitution of hydrogen. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Research paper thumbnail of Tele vs. Oxidative Substitution of Hydrogen inmeta Monochloromethyl, Dichloromethyl, and Trichloromethyl Nitrobenzenes in the Reaction with Grignard Reagents

European Journal of Organic Chemistry, 2003

ABSTRACT Grignard reagents add to nitrobenzene derivatives containing trichloromethyl, dichlorome... more ABSTRACT Grignard reagents add to nitrobenzene derivatives containing trichloromethyl, dichloromethyl, and monochloromethyl groups in the meta position to form σH adducts, which are either further converted through departure of a chloride anion, giving products of tele substitution, or oxidized to products of oxidative nucleophilic substitution of hydrogen. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Research paper thumbnail of Abnormal Nucleophilic Substitution in 3-Trichloromethylpyridine, its N-Oxide and 3,5-Bis(trichloromethyl)pyridine

Tetrahedron, Nov 1, 1995

The scope of abnormal reactions of nucleophiles with β-trichloromethylazines is further explored:... more The scope of abnormal reactions of nucleophiles with β-trichloromethylazines is further explored: reactions of 3-trichloromethylpyridine with nucleophiles other than methoxide, and reactions of 3-trichloromethylpyridine N-oxide and 3,5-bis(trichloromethyl)pyridine with methoxide. Attack at a ring carbon, followed by hydrogen migration to the side-chain, occurred in most cases, though attack at the trichloromethyl carbon was also sometimes observed.We now report further studies on

Research paper thumbnail of Determination of plasma, urine, and bovine serum albumin low-molecular-weight carbonyl levels by capillary gas chromatography with electron-capture and mass-selective detection

Analytical Biochemistry, 2005

Peroxidation of lipids produces low-molecular-weight carbonyl compounds, which are reactive with ... more Peroxidation of lipids produces low-molecular-weight carbonyl compounds, which are reactive with biological nucleophiles. The analysis of these compounds is often diYcult. A multicomponent method for the determination of 11 of them in biological samples is reported. The samples are subjected to a pretreatment-derivatization procedure followed by gas chromatographic analysis with either electron-capture detection (ECD) or mass-selective detection (MSD) in the selected-ion monitoring mode. The procedure involves derivatization of the analyte with 2,4,6-trichlorophenylhydrazine, extraction with n-hexane, and separation of the derivatization products on a nonpolar gas chromatographic column. The concentration of the derivatization reagent, pH, reaction time, temperature, and presence of extraneous ions were investigated to determine the optimal derivatization conditions. Under these conditions, the method allows for the selective detection of low-molecular-weight carbonyl compounds at femtomole levels in several biological materials such as plasma, urine, and bovine serum albumin without interferences. The limits of detection were in the ranges 0.01-0.2 M for ECD and 0.15-1.5 M for MSD. The mean procedural recoveries obtained during the method validation were within the range 85-95% and the intra-and interassay standard deviations do not exceed 4.6 and 6.1%, respectively.

Research paper thumbnail of ChemInform Abstract: Synthesis, Chemistry, and Biological Properties of Thienopyrimidines

Research paper thumbnail of ChemInform Abstract: Abnormal Nucleophilic Substitution in 3-Trichloromethylpyridine, Its N- Oxide and 3,5Bis(trichloromethyl)pyridine

Research paper thumbnail of ChemInform Abstract: Synthesis of Some β-Trichloromethylazines and -diazines

Cheminform, 2010

Synthesis of Some β-Trichloromethylazines and -diazines.

Research paper thumbnail of Synthesis of some ?-trichloromethyl-azines and -diazines

Journal of The Chemical Society-perkin Transactions 1, 1995

ABSTRACT Syntheses of compounds required as substrates for reactions with nucleophiles are report... more ABSTRACT Syntheses of compounds required as substrates for reactions with nucleophiles are reported: 2-trichloromethylquinoxaline 5, 3-trichloromethylquinoline 6, 3,5-bis(trichloromethyl)pyridine 7, 2,5-bis(trichloromethyl)pyrazine 8 and 5-trichloromethylpyrimidine 9.

Research paper thumbnail of Abnormal Nucleophilic Substitution in 3-Trichloromethylpyridine, its N-Oxide and 3,5Bis(trichloromethyl)pyridine

Tetrahedron, 1995

The scope of abnormal reactions of nucleophiles with β-trichloromethylazines is further explored:... more The scope of abnormal reactions of nucleophiles with β-trichloromethylazines is further explored: reactions of 3-trichloromethylpyridine with nucleophiles other than methoxide, and reactions of 3-trichloromethylpyridine N-oxide and 3,5-bis(trichloromethyl)pyridine with methoxide. Attack at a ring carbon, followed by hydrogen migration to the side-chain, occurred in most cases, though attack at the trichloromethyl carbon was also sometimes observed.We now report further studies on

Research paper thumbnail of ChemInform Abstract: Tele Nucleophilic Aromatic Substitutions in 1-Nitro-3- and 1,3-Dinitro-5-trichloromethylbenzene, and 3-Trichloromethylbenzonitrile. A New Synthesis of the 1,4-Benzothiazine-3(4H)-one Ring System from 3-Nitrobenzoic Acid

Research paper thumbnail of Tele Nucleophilic Aromatic Substitutions in 1Nitro3- and 1,3-Dinitro-5-trichloromethylbenzene, and 3-Trichloromethylbenzonitrile. A New Synthesis of the 1,4-Benzothiazine-3(4 H)-one Ring System from 3-Nitrobenzoic Acid

Tetrahedron, 2000

3-Trichloromethylnitrobenzene 2, 1,3-dinitro-5-trichloromethylbenzene 13 and 3-trichloromethylben... more 3-Trichloromethylnitrobenzene 2, 1,3-dinitro-5-trichloromethylbenzene 13 and 3-trichloromethylbenzonitrile 18 react with sodium methoxide to give 4-methoxy-3-nitrobenzaldehyde 6, 4-methoxy-3,5-dinitrobenzaldehyde 15 and 5-dimethoxymethyl-2-methoxybenzonitrile 19, respectively. Compounds 2 and 13 react with methyl thioglycolate to afford dichloromethylacetates 7 and 16, respectively. These products are the result of tele nucleophilic aromatic substitution. Compound 18 reacted with methyl thioglycolate to give acetate 20 resulting from nucleophilic displacement

Research paper thumbnail of Synthesis, Chemistry, and Biological Properties of Thienopyrimidines

Advances in Heterocyclic Chemistry, 1996

Research paper thumbnail of Physicochemical study of novel organoclays as heavy metal ion adsorbents for environmental remediation

Journal of Colloid and Interface Science, 2007

Four organic-modified clays based on a SWy-2 montmorillonite were prepared by embedding ammonium ... more Four organic-modified clays based on a SWy-2 montmorillonite were prepared by embedding ammonium organic derivatives with different chelating functionalities (-NH 2 , -COOH, -SH or -CS 2 ) in the interlayer space of montmorillonite. Organic molecules such as (a) hexamethylenediamine, (b) 2-(dimethylamino)ethenethiol, (c) 5-aminovaleric acid and (d) hexamethylenediamine-dithiocarbamate were used for the clay modification in order to study the effect of the chelating functionality on heavy metal ions binding from aqueous solutions. The organoclays were characterized by powder X-ray diffraction (XRD), infrared (FTIR) and NMR spectroscopies. The experimental data showed that the organic molecules are intercalated into the interlamelar space with the long dimension parallel to the clay sheets. Their sorbing properties were evaluated for the removal of heavy metals, Pb, Cd and Zn, from aqueous solutions as a function of the pH. When compared with the unmodified SWy-2 montmorillonite, the modified clays show significant improvement in terms of sorbing selectivity as well as of metal loading capacity. The fit to adsorption data by a Surface Complexation Model shows that the intercalated molecules act as specific binding sites in the clay. These contribute additional sorption capacity which is additive to the variable charge edge-sites of the clay in competition with the permanent charge sites. (Y. Deligiannakis). heavy metals. Moreover, due to their abundance in soil systems, their high specific surface area and exchange capacity, clay minerals such as montmorillonite play a significant role in determining the availability and transport of metals species in soil and sediments .

Research paper thumbnail of Tele vs. Oxidative Substitution of Hydrogen inmeta Monochloromethyl, Dichloromethyl, and Trichloromethyl Nitrobenzenes in the Reaction with Grignard Reagents

European Journal of Organic Chemistry, 2003

ABSTRACT Grignard reagents add to nitrobenzene derivatives containing trichloromethyl, dichlorome... more ABSTRACT Grignard reagents add to nitrobenzene derivatives containing trichloromethyl, dichloromethyl, and monochloromethyl groups in the meta position to form σH adducts, which are either further converted through departure of a chloride anion, giving products of tele substitution, or oxidized to products of oxidative nucleophilic substitution of hydrogen. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)