Ditellurino[2,3-b:5,6-b 0 ]dipyrazine represents the first reported [1,4]chalcogena[2,3-b:5,6-b 0... more Ditellurino[2,3-b:5,6-b 0 ]dipyrazine represents the first reported [1,4]chalcogena[2,3-b:5,6-b 0 ]dipyrazine containing a heavy chalcogens The asymmetric unit consists of three molecules. In contrast to its sulfur analog, which is planar [Lynch et al. (1994) Cryst. Struct. Commun. 50,1470-1472], C 8 H 4 N 4 Te 2 is folded along the TeÁ Á ÁTe axis to accommodate the larger chalcogenide atoms. The dihedral angle between the two Te 2 C 2 rings of the central ring is 57.9 (mean of three). C-Te bond lengths range from 2.1105 (16) Å to 2.1381 (17) Å , in good agreement with those predicted by their covalent radii. All Te atoms are involved in intermolecular TeÁ Á ÁN contacts, with distances in the range 2.894 (2) to 2.963 (2) Å. These result in a spiral supramolecular assembly, forming helical columns. Structure description Heterocyclic tellurium compounds have found considerable attention due to their tendency to form supramolecular assemblies including molecular wires (Kremer et al., 2016), ribbons (Cozzolino et al., 2010) and rings (Ho et al., 2016, 2017). Such assembles can give rise to materials with non-linear optical properties (Cozzolino et al., 2010), as well as novel phosphorescent organic emitters (Kremer et al., 2015). A ribbon motif resulting from secondary intermolecular NÁ Á ÁTe bonding interactions of 2.767 (6) and 2.659 (6) Å was reported for 3,4-dicyano-1,2,5-telluradiazole (Cozzolino et al., 2010). Similarly, molecular wire motifs resulting from secondary intermolecular NÁ Á ÁTe bonding were observed for 2-substituted benzo-1,3-tellurazoles, but with significantly longer NÁ Á ÁTe distances. This is exemplified by 2-(2-furanyl) benzo-1,3-tellurazole, 3.17 Å (Kremer et al., 2016) and 1,3-benzotellurazol-2-ylacetonitrile, 3.16 Å (Sanford et al., 2017). Not all Te, N-containing heterocycles form supramolecular wires or ribbons. Thus, 10H-pyrazino[2,3-b][1,4]benzotellurazine (Smith et al., 2020), 2H-1,4-benzo-tellurazin-3(4H)-one and 2,3-dihydro-1,5-benzotellurazepin-4(5H)-one (Myers et al., 2016) lack this
Dinuclear Ni(ii)-, Cu(ii)-, Zn(ii)- and Mn(ii)-acetato complexes have been used in the cleavage o... more Dinuclear Ni(ii)-, Cu(ii)-, Zn(ii)- and Mn(ii)-acetato complexes have been used in the cleavage of DNA and the hydrolysis of BDNPP.
Acta Crystallographica Section C Crystal Structure Communications, 2003
All three title compounds, prepared from bis(3,5-dimethyl-2nitrophenyl)ditellurium, exhibit high ... more All three title compounds, prepared from bis(3,5-dimethyl-2nitrophenyl)ditellurium, exhibit high degrees of intramolecular TeÐO coordination. Their TeÐO distances increase in the order C 8 H 8 BrNOTe < C 8 H 8 BrNO 2 Te < C 8 H 8 Br 3 NO 2 Te, with distances of 2.165 (3), 2.306 (1) and 2.423 (6) A Ê , respectively, indicating that C 8 H 8 BrNOTe may be more aptly described as 1-bromo-4,6-dimethyl-2,1,3-benzoxatellurazole.
Dalton transactions (Cambridge, England : 2003), Jan 20, 2015
The reaction of a methanolic solution containing the bi-compartmental phenolic ligand 2,6-bis[bis... more The reaction of a methanolic solution containing the bi-compartmental phenolic ligand 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-chlorophenol (L(Cl)-OH) with MCl2·nH2O in the presence of NH4PF6 or NaClO4 afforded the dinuclear bridged-phenoxido dichlorido-metal(ii) complexes [Co2(μ-L(Cl)O)(H2O)2Cl2][Co2(μ-L(Cl)O)(MeOH)2Cl2](PF6)2 (), [Ni2(μ-L(Cl)O)(MeOH)2Cl2]PF6 (), [Ni2(μ-L(Cl)O)(MeOH)(H2O)Cl2]ClO4·1.25H2O (), [Cu2(μ-L(Cl)O)Cl2]PF6·1/2MeOH () and [Zn2(μ-L(Cl)O)Cl2]PF6·MeOH (). The complexes were characterized by elemental microanalyses, conductivity measurements, IR and UV-Vis spectroscopy, mass spectrometry and single crystal X-ray crystallography. Each M(ii) center within the dinuclear complex cations is octahedrally coordinated in complexes , and five-coordinated distorted square pyramidal in and . Magnetic susceptibility measurements at variable temperature of the complexes revealed weak to moderate antiferromagnetic coupling with |J| values = 8.38, 39.0, 30.2 and 0.79 cm(-1), ...
Bromoaromatics are ubiquitous in chemistry, and their manufacture is often wasteful. Halogen exch... more Bromoaromatics are ubiquitous in chemistry, and their manufacture is often wasteful. Halogen exchange under hydrothermal conditions constitutes a viable alternative for their synthesis in some cases. The preparation of 1,2-dibromobenzene and 1-bromo-2-chlorobenzene from 1,2-dichlorobenzene, by treatment with hydrobromic acid in hydrothermal media at temperatures ranging from 240˚C to 320˚C was investigated as a viable alternative to de novo synthesis. The effects of temperature, exchange duration and the presence of Fe 3+ salts on product yields are discussed. Yields for both targeted haloarenes of up to 37% and 48%, respectively, were achieved, with very limited formation of 1,3-and 1,4-dihalobenzene isomers. A mechanism for halogen exchange was proposed.
The1H and13C chemical shifts as well as the1H–2H and2H–13C coupling constants of perdeuterated 3,... more The1H and13C chemical shifts as well as the1H–2H and2H–13C coupling constants of perdeuterated 3,5-dimethylpyrazole and 3,5-diphenylpyrazole have been measured and the values compared with those of the unlabelled compounds.
... W. James Catallo1 (u) · Jay L. Comeaux2 (u) · Thomas Junk3 (u) 1Comparative Biomedical Scienc... more ... W. James Catallo1 (u) · Jay L. Comeaux2 (u) · Thomas Junk3 (u) 1Comparative Biomedical Sciences Department, School of Veterinary ... This work addresses the possible deployment of sediments contami-nated with aromatic hydrocarbons (AHs) in salt marsh creation efforts. ...
A general, post-synthetic labeling method for the preparation of fully deuteratedpyrazolesand qui... more A general, post-synthetic labeling method for the preparation of fully deuteratedpyrazolesand quinoxalinesby base-inducedisotopeexchangein superheated deuteriumoxideis described. Examplesincludethe synthesisof 2-methylquinoxaline+&, 2,3-dimethylquinoxaline-d10, 3,5-dimethylpyrazole-d8, and3,5-diphenylpyrazole-dlz.
Deuterated homo-and heterocyclic aromatic substrates bearing various functionalities were prepare... more Deuterated homo-and heterocyclic aromatic substrates bearing various functionalities were prepared by isotope exchange in supercritical deuterium oxide, with little or no formation of byproducts. Equilibration was attained rapidly (1-24 hrs), and deuterium exchange extended to alpha positions of alkyl homologs. Nitroand haloarenes, thioethers, telluroethers, and some heterocyclic substrates were unstable.
Journal of Labelled Compounds and Radiopharmaceuticals, 2013
Methods for the preparation of deuterium‐labeled analogs to six prominent biotransformation produ... more Methods for the preparation of deuterium‐labeled analogs to six prominent biotransformation products of the explosive 2,4,6‐trinitrotoluene were developed. These are useful as reference standards for stable isotope dilution techniques and for solid state 2H NMR spectroscopic studies. Although syntheses for most of the target compounds in protiated form had been reported in the past, most of those were found to be poorly suited for the preparation of the deuterated materials. Selective reduction of [2H5]trinitrotoluene furnished [2H5]‐4,6‐dinitro‐2‐hydroxylaminotoluene, [2H5]‐2,6‐dinitro‐4‐hydroxylaminotoluene, [2H5]‐2‐amino‐4,6‐dinitrotoluene, and [2H5]‐4‐amino‐2,6‐dinitrotoluene. The syntheses of [2H10]‐2,2′‐azo‐4,4′,6,6′‐tetranitrotoluene and [2H10]‐4,4′‐azo‐2,2′,6,6′‐tetranitrotoluene were accomplished by selective oxidation of [2H5]‐2‐amino‐4,6‐dinitrotoluene and [2H5]‐4‐amino‐2,6‐dinitrotoluene, respectively.
Journal of Labelled Compounds and Radiopharmaceuticals, 1997
ABSTRACT 2-[2H]Benzothiazole, readily available according to the literature, was observed to unde... more ABSTRACT 2-[2H]Benzothiazole, readily available according to the literature, was observed to undergo slow isotope exchange in water. This necessitated development of practical syntheses for benzothiazoles carrying deuterium lables in positions other than 2 [4,5,6,7-2H4]Benzothiazole and 4-[2H3]methyl[5,6,7-2H3]benzothiazole were prepared in good yield from [2H7]aniline and 2-[2H9]toluidine, which were obtained by novel rapid isotope exchange in supercritical deuterium oxide.
ABSTRACTBenzothiazole (BT) is a natural and synthetic compound occurring in aquatic sediments and... more ABSTRACTBenzothiazole (BT) is a natural and synthetic compound occurring in aquatic sediments and wastewater. The purpose of this work was to investigate BT biogeochemistry in controlled Eh/pH microcosms (CEPMs) containing estuarine sediments of different particle sizes (coarse, intermediate, fine) under oxidized and reduced conditions vs. killed controls, and tide simulation mesocosms (TSMs) containing plants and meiofauna under well‐drained (oxidized), consistently saturated/flooded (reduced), and tidal (alternating oxidized/reduced) conditions. Benzothiazole was transformed into complex product mixtures under all conditions. Benzothiazole transformation rates in CEPMs were slower under reduced conditions vs. oxidized conditions in the fine‐ and intermediate‐grain sediments, but the same in the coarse sediment. Quiescent (unstirred) CEPMs showed greatly reduced BT transformation rates in all sediments, with half‐lives on the order of 2200 to >4000 h (unstirred) vs. 640 to 1000 ...
Synthese de phenotellurazine et de benzo [a] phenotellurazine, a partir de diphenylamine et de ph... more Synthese de phenotellurazine et de benzo [a] phenotellurazine, a partir de diphenylamine et de phenyl 2-naphtyl amine, respectivement
Arsenic analogs of lecithins (i.e. with replacement of nitrogen by arsenic in the choline group) ... more Arsenic analogs of lecithins (i.e. with replacement of nitrogen by arsenic in the choline group) are probably trace constituents of phospholipids in many organisms. Attempts to synthesize 1,2‐bis(palmitoyloxy)‐3‐propyl 2‐trimethylarsonioethyl phosphate (arsenolecithin) according to wellestablished procedures for the synthesis of the corresponding nitrogen compound failed. However, 1,2‐bis(palmitoyloxy)‐3‐propyl 2‐trimethylarsonioethylphosphonate, an arsenic‐containing phosphonolipid, was obtained in 16% yield by reacting 1,2‐bis(palmitoyloxy)‐3‐iodopropane with silver 2‐trimethylarsonioethylphosphonate in isopropanol. The precursors to the arsenic‐containing phosphonolipid were obtained by quaternization of trimethylarsine with diethyl 2‐bromoethylphosphonate, hydrolysis of the resulting product with concentrated hydrochloric acid, and reaction of the phosphonic acid with silver oxide to give silver 2‐trimethylarsonioethylphosphonate. Quaternization and hydrolysis proceeded almost q...
Trimethyl‐2‐X‐ethylarsonium salts (X=OH, Cl, Br, CH3COO; anion=Br) and trimethyl‐2‐diethoxyethyla... more Trimethyl‐2‐X‐ethylarsonium salts (X=OH, Cl, Br, CH3COO; anion=Br) and trimethyl‐2‐diethoxyethylarsonium bromide were prepared from trimethylarsine and the appropriate organic bromides in sealed tubes at elevated temperatures or by refluxing the neat reagents. The yields ranged from 33 to 85%. Anion exchange reactions produced the arsonium iodides, nitrates, acetates, tosylates, tetraphenylborates, picrates, hydroxides, and carbonates. Arsenocholine bromide (X=OH) was phosphorylated with concentrated phosphoric acid. The product was isolated as the barium salt. Treatment of the barium salt with sulfuric acid yielded trimethyl‐2‐(dihydrogen phosphato)ethylarsonium bromide. These substances were synthesized to serve as precursors for arsenic‐ containing phospholipids and as standards for the chromatographic identification of arsenocholines. The synthesized compounds were characterized by elemental analyses and 1H and 13C NMR spectroscopy. The shifts of the arsenic compounds were compa...
Synthetic methods have been developed to prepare novel 1,3-benzotellurazoles carrying acylamino a... more Synthetic methods have been developed to prepare novel 1,3-benzotellurazoles carrying acylamino and arylamino moieties in position 2, in order to investigate their propensity to self-assemble to supramolecular structures. The targeted compounds were obtained in yields ranging from 44% to 67%, by reacting bis(2-aminophenyl) ditelluride with acyl-and aryl isothiocyanates, respectively, and subsequent reductive cyclization of the resulting thiourea derivatives. Seven novel 1,3benzotellurazole derivatives were prepared: 2-benzoylamino-1,3-benzotellurazole, 2-(4-chlorobenzoylamino)-1,3benzotellurazole, 2-(2-bromobenzoylamino)-1,3-benzotellurazole, 2-(4-bromobenzoylamino)-1,3-benzotellurazole, 2-(4methoxybenzoylamino)-1,3-benzotellurazole, 2-phenylamino-1,3-benzotellurazole, and 2-(4-chlorophenylamino-1,3benzotellurazole. A simplified protocol was employed to synthesize all acyl isothiocyanates needed for their preparation from benzoyl halide derivatives and potassium thiocyanate. The reductive cyclization of the intermediate thioureas was challenging, only the use of hydroxymethanesulfinate in the presence of elemental mercury provided synthetically useful product yields. A mechanism was proposed, consisting of the insertion of mercury into the Te-Te bond, followed by intramolecular nucleophilic attack of the thiocarbonyl moiety by the resulting insertion product. All 2-acylamino-1,3-benzotellurazoles are crystalline solids, which are stable to ambient light, air and moderate heat. A characterization of selected samples by X-ray crystallography indicated that they form dimers in solid state, resulting from hydrogen bonding between the exocyclic and endocyclic nitrogen atoms of two adjacent molecules. This sets them apart from 2-alkyl-and 2-aryl-1,3-benzotellurazoles, which are known to self-assemble into supramolecular wires.
Condensation of 2,3-dichloropyrazine with 2-aminobenzenetellurole and 2-amino-5-methylbenzenetell... more Condensation of 2,3-dichloropyrazine with 2-aminobenzenetellurole and 2-amino-5-methylbenzenetellurole, generated in situ by reduction of the corresponding ditellurides, resulted in the formation of novel 10H-pyrazino[2,3-b][1,4]benzotellurazine and its 7-methyl derivative. The products were purified via their well-crystallized 5,5-dibromo derivatives. X-ray crystallographic analysis of the title compound indicates that it has a pronounced V-shape and forms hydrogen-bonded dimers. Te, N-containing heterocycles have the potential of offering access to supramolecular assemblies.
Ditellurino[2,3-b:5,6-b 0 ]dipyrazine represents the first reported [1,4]chalcogena[2,3-b:5,6-b 0... more Ditellurino[2,3-b:5,6-b 0 ]dipyrazine represents the first reported [1,4]chalcogena[2,3-b:5,6-b 0 ]dipyrazine containing a heavy chalcogens The asymmetric unit consists of three molecules. In contrast to its sulfur analog, which is planar [Lynch et al. (1994) Cryst. Struct. Commun. 50,1470-1472], C 8 H 4 N 4 Te 2 is folded along the TeÁ Á ÁTe axis to accommodate the larger chalcogenide atoms. The dihedral angle between the two Te 2 C 2 rings of the central ring is 57.9 (mean of three). C-Te bond lengths range from 2.1105 (16) Å to 2.1381 (17) Å , in good agreement with those predicted by their covalent radii. All Te atoms are involved in intermolecular TeÁ Á ÁN contacts, with distances in the range 2.894 (2) to 2.963 (2) Å. These result in a spiral supramolecular assembly, forming helical columns. Structure description Heterocyclic tellurium compounds have found considerable attention due to their tendency to form supramolecular assemblies including molecular wires (Kremer et al., 2016), ribbons (Cozzolino et al., 2010) and rings (Ho et al., 2016, 2017). Such assembles can give rise to materials with non-linear optical properties (Cozzolino et al., 2010), as well as novel phosphorescent organic emitters (Kremer et al., 2015). A ribbon motif resulting from secondary intermolecular NÁ Á ÁTe bonding interactions of 2.767 (6) and 2.659 (6) Å was reported for 3,4-dicyano-1,2,5-telluradiazole (Cozzolino et al., 2010). Similarly, molecular wire motifs resulting from secondary intermolecular NÁ Á ÁTe bonding were observed for 2-substituted benzo-1,3-tellurazoles, but with significantly longer NÁ Á ÁTe distances. This is exemplified by 2-(2-furanyl) benzo-1,3-tellurazole, 3.17 Å (Kremer et al., 2016) and 1,3-benzotellurazol-2-ylacetonitrile, 3.16 Å (Sanford et al., 2017). Not all Te, N-containing heterocycles form supramolecular wires or ribbons. Thus, 10H-pyrazino[2,3-b][1,4]benzotellurazine (Smith et al., 2020), 2H-1,4-benzo-tellurazin-3(4H)-one and 2,3-dihydro-1,5-benzotellurazepin-4(5H)-one (Myers et al., 2016) lack this
Dinuclear Ni(ii)-, Cu(ii)-, Zn(ii)- and Mn(ii)-acetato complexes have been used in the cleavage o... more Dinuclear Ni(ii)-, Cu(ii)-, Zn(ii)- and Mn(ii)-acetato complexes have been used in the cleavage of DNA and the hydrolysis of BDNPP.
Acta Crystallographica Section C Crystal Structure Communications, 2003
All three title compounds, prepared from bis(3,5-dimethyl-2nitrophenyl)ditellurium, exhibit high ... more All three title compounds, prepared from bis(3,5-dimethyl-2nitrophenyl)ditellurium, exhibit high degrees of intramolecular TeÐO coordination. Their TeÐO distances increase in the order C 8 H 8 BrNOTe < C 8 H 8 BrNO 2 Te < C 8 H 8 Br 3 NO 2 Te, with distances of 2.165 (3), 2.306 (1) and 2.423 (6) A Ê , respectively, indicating that C 8 H 8 BrNOTe may be more aptly described as 1-bromo-4,6-dimethyl-2,1,3-benzoxatellurazole.
Dalton transactions (Cambridge, England : 2003), Jan 20, 2015
The reaction of a methanolic solution containing the bi-compartmental phenolic ligand 2,6-bis[bis... more The reaction of a methanolic solution containing the bi-compartmental phenolic ligand 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-chlorophenol (L(Cl)-OH) with MCl2·nH2O in the presence of NH4PF6 or NaClO4 afforded the dinuclear bridged-phenoxido dichlorido-metal(ii) complexes [Co2(μ-L(Cl)O)(H2O)2Cl2][Co2(μ-L(Cl)O)(MeOH)2Cl2](PF6)2 (), [Ni2(μ-L(Cl)O)(MeOH)2Cl2]PF6 (), [Ni2(μ-L(Cl)O)(MeOH)(H2O)Cl2]ClO4·1.25H2O (), [Cu2(μ-L(Cl)O)Cl2]PF6·1/2MeOH () and [Zn2(μ-L(Cl)O)Cl2]PF6·MeOH (). The complexes were characterized by elemental microanalyses, conductivity measurements, IR and UV-Vis spectroscopy, mass spectrometry and single crystal X-ray crystallography. Each M(ii) center within the dinuclear complex cations is octahedrally coordinated in complexes , and five-coordinated distorted square pyramidal in and . Magnetic susceptibility measurements at variable temperature of the complexes revealed weak to moderate antiferromagnetic coupling with |J| values = 8.38, 39.0, 30.2 and 0.79 cm(-1), ...
Bromoaromatics are ubiquitous in chemistry, and their manufacture is often wasteful. Halogen exch... more Bromoaromatics are ubiquitous in chemistry, and their manufacture is often wasteful. Halogen exchange under hydrothermal conditions constitutes a viable alternative for their synthesis in some cases. The preparation of 1,2-dibromobenzene and 1-bromo-2-chlorobenzene from 1,2-dichlorobenzene, by treatment with hydrobromic acid in hydrothermal media at temperatures ranging from 240˚C to 320˚C was investigated as a viable alternative to de novo synthesis. The effects of temperature, exchange duration and the presence of Fe 3+ salts on product yields are discussed. Yields for both targeted haloarenes of up to 37% and 48%, respectively, were achieved, with very limited formation of 1,3-and 1,4-dihalobenzene isomers. A mechanism for halogen exchange was proposed.
The1H and13C chemical shifts as well as the1H–2H and2H–13C coupling constants of perdeuterated 3,... more The1H and13C chemical shifts as well as the1H–2H and2H–13C coupling constants of perdeuterated 3,5-dimethylpyrazole and 3,5-diphenylpyrazole have been measured and the values compared with those of the unlabelled compounds.
... W. James Catallo1 (u) · Jay L. Comeaux2 (u) · Thomas Junk3 (u) 1Comparative Biomedical Scienc... more ... W. James Catallo1 (u) · Jay L. Comeaux2 (u) · Thomas Junk3 (u) 1Comparative Biomedical Sciences Department, School of Veterinary ... This work addresses the possible deployment of sediments contami-nated with aromatic hydrocarbons (AHs) in salt marsh creation efforts. ...
A general, post-synthetic labeling method for the preparation of fully deuteratedpyrazolesand qui... more A general, post-synthetic labeling method for the preparation of fully deuteratedpyrazolesand quinoxalinesby base-inducedisotopeexchangein superheated deuteriumoxideis described. Examplesincludethe synthesisof 2-methylquinoxaline+&, 2,3-dimethylquinoxaline-d10, 3,5-dimethylpyrazole-d8, and3,5-diphenylpyrazole-dlz.
Deuterated homo-and heterocyclic aromatic substrates bearing various functionalities were prepare... more Deuterated homo-and heterocyclic aromatic substrates bearing various functionalities were prepared by isotope exchange in supercritical deuterium oxide, with little or no formation of byproducts. Equilibration was attained rapidly (1-24 hrs), and deuterium exchange extended to alpha positions of alkyl homologs. Nitroand haloarenes, thioethers, telluroethers, and some heterocyclic substrates were unstable.
Journal of Labelled Compounds and Radiopharmaceuticals, 2013
Methods for the preparation of deuterium‐labeled analogs to six prominent biotransformation produ... more Methods for the preparation of deuterium‐labeled analogs to six prominent biotransformation products of the explosive 2,4,6‐trinitrotoluene were developed. These are useful as reference standards for stable isotope dilution techniques and for solid state 2H NMR spectroscopic studies. Although syntheses for most of the target compounds in protiated form had been reported in the past, most of those were found to be poorly suited for the preparation of the deuterated materials. Selective reduction of [2H5]trinitrotoluene furnished [2H5]‐4,6‐dinitro‐2‐hydroxylaminotoluene, [2H5]‐2,6‐dinitro‐4‐hydroxylaminotoluene, [2H5]‐2‐amino‐4,6‐dinitrotoluene, and [2H5]‐4‐amino‐2,6‐dinitrotoluene. The syntheses of [2H10]‐2,2′‐azo‐4,4′,6,6′‐tetranitrotoluene and [2H10]‐4,4′‐azo‐2,2′,6,6′‐tetranitrotoluene were accomplished by selective oxidation of [2H5]‐2‐amino‐4,6‐dinitrotoluene and [2H5]‐4‐amino‐2,6‐dinitrotoluene, respectively.
Journal of Labelled Compounds and Radiopharmaceuticals, 1997
ABSTRACT 2-[2H]Benzothiazole, readily available according to the literature, was observed to unde... more ABSTRACT 2-[2H]Benzothiazole, readily available according to the literature, was observed to undergo slow isotope exchange in water. This necessitated development of practical syntheses for benzothiazoles carrying deuterium lables in positions other than 2 [4,5,6,7-2H4]Benzothiazole and 4-[2H3]methyl[5,6,7-2H3]benzothiazole were prepared in good yield from [2H7]aniline and 2-[2H9]toluidine, which were obtained by novel rapid isotope exchange in supercritical deuterium oxide.
ABSTRACTBenzothiazole (BT) is a natural and synthetic compound occurring in aquatic sediments and... more ABSTRACTBenzothiazole (BT) is a natural and synthetic compound occurring in aquatic sediments and wastewater. The purpose of this work was to investigate BT biogeochemistry in controlled Eh/pH microcosms (CEPMs) containing estuarine sediments of different particle sizes (coarse, intermediate, fine) under oxidized and reduced conditions vs. killed controls, and tide simulation mesocosms (TSMs) containing plants and meiofauna under well‐drained (oxidized), consistently saturated/flooded (reduced), and tidal (alternating oxidized/reduced) conditions. Benzothiazole was transformed into complex product mixtures under all conditions. Benzothiazole transformation rates in CEPMs were slower under reduced conditions vs. oxidized conditions in the fine‐ and intermediate‐grain sediments, but the same in the coarse sediment. Quiescent (unstirred) CEPMs showed greatly reduced BT transformation rates in all sediments, with half‐lives on the order of 2200 to >4000 h (unstirred) vs. 640 to 1000 ...
Synthese de phenotellurazine et de benzo [a] phenotellurazine, a partir de diphenylamine et de ph... more Synthese de phenotellurazine et de benzo [a] phenotellurazine, a partir de diphenylamine et de phenyl 2-naphtyl amine, respectivement
Arsenic analogs of lecithins (i.e. with replacement of nitrogen by arsenic in the choline group) ... more Arsenic analogs of lecithins (i.e. with replacement of nitrogen by arsenic in the choline group) are probably trace constituents of phospholipids in many organisms. Attempts to synthesize 1,2‐bis(palmitoyloxy)‐3‐propyl 2‐trimethylarsonioethyl phosphate (arsenolecithin) according to wellestablished procedures for the synthesis of the corresponding nitrogen compound failed. However, 1,2‐bis(palmitoyloxy)‐3‐propyl 2‐trimethylarsonioethylphosphonate, an arsenic‐containing phosphonolipid, was obtained in 16% yield by reacting 1,2‐bis(palmitoyloxy)‐3‐iodopropane with silver 2‐trimethylarsonioethylphosphonate in isopropanol. The precursors to the arsenic‐containing phosphonolipid were obtained by quaternization of trimethylarsine with diethyl 2‐bromoethylphosphonate, hydrolysis of the resulting product with concentrated hydrochloric acid, and reaction of the phosphonic acid with silver oxide to give silver 2‐trimethylarsonioethylphosphonate. Quaternization and hydrolysis proceeded almost q...
Trimethyl‐2‐X‐ethylarsonium salts (X=OH, Cl, Br, CH3COO; anion=Br) and trimethyl‐2‐diethoxyethyla... more Trimethyl‐2‐X‐ethylarsonium salts (X=OH, Cl, Br, CH3COO; anion=Br) and trimethyl‐2‐diethoxyethylarsonium bromide were prepared from trimethylarsine and the appropriate organic bromides in sealed tubes at elevated temperatures or by refluxing the neat reagents. The yields ranged from 33 to 85%. Anion exchange reactions produced the arsonium iodides, nitrates, acetates, tosylates, tetraphenylborates, picrates, hydroxides, and carbonates. Arsenocholine bromide (X=OH) was phosphorylated with concentrated phosphoric acid. The product was isolated as the barium salt. Treatment of the barium salt with sulfuric acid yielded trimethyl‐2‐(dihydrogen phosphato)ethylarsonium bromide. These substances were synthesized to serve as precursors for arsenic‐ containing phospholipids and as standards for the chromatographic identification of arsenocholines. The synthesized compounds were characterized by elemental analyses and 1H and 13C NMR spectroscopy. The shifts of the arsenic compounds were compa...
Synthetic methods have been developed to prepare novel 1,3-benzotellurazoles carrying acylamino a... more Synthetic methods have been developed to prepare novel 1,3-benzotellurazoles carrying acylamino and arylamino moieties in position 2, in order to investigate their propensity to self-assemble to supramolecular structures. The targeted compounds were obtained in yields ranging from 44% to 67%, by reacting bis(2-aminophenyl) ditelluride with acyl-and aryl isothiocyanates, respectively, and subsequent reductive cyclization of the resulting thiourea derivatives. Seven novel 1,3benzotellurazole derivatives were prepared: 2-benzoylamino-1,3-benzotellurazole, 2-(4-chlorobenzoylamino)-1,3benzotellurazole, 2-(2-bromobenzoylamino)-1,3-benzotellurazole, 2-(4-bromobenzoylamino)-1,3-benzotellurazole, 2-(4methoxybenzoylamino)-1,3-benzotellurazole, 2-phenylamino-1,3-benzotellurazole, and 2-(4-chlorophenylamino-1,3benzotellurazole. A simplified protocol was employed to synthesize all acyl isothiocyanates needed for their preparation from benzoyl halide derivatives and potassium thiocyanate. The reductive cyclization of the intermediate thioureas was challenging, only the use of hydroxymethanesulfinate in the presence of elemental mercury provided synthetically useful product yields. A mechanism was proposed, consisting of the insertion of mercury into the Te-Te bond, followed by intramolecular nucleophilic attack of the thiocarbonyl moiety by the resulting insertion product. All 2-acylamino-1,3-benzotellurazoles are crystalline solids, which are stable to ambient light, air and moderate heat. A characterization of selected samples by X-ray crystallography indicated that they form dimers in solid state, resulting from hydrogen bonding between the exocyclic and endocyclic nitrogen atoms of two adjacent molecules. This sets them apart from 2-alkyl-and 2-aryl-1,3-benzotellurazoles, which are known to self-assemble into supramolecular wires.
Condensation of 2,3-dichloropyrazine with 2-aminobenzenetellurole and 2-amino-5-methylbenzenetell... more Condensation of 2,3-dichloropyrazine with 2-aminobenzenetellurole and 2-amino-5-methylbenzenetellurole, generated in situ by reduction of the corresponding ditellurides, resulted in the formation of novel 10H-pyrazino[2,3-b][1,4]benzotellurazine and its 7-methyl derivative. The products were purified via their well-crystallized 5,5-dibromo derivatives. X-ray crystallographic analysis of the title compound indicates that it has a pronounced V-shape and forms hydrogen-bonded dimers. Te, N-containing heterocycles have the potential of offering access to supramolecular assemblies.
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