Analysis of chlorinated, sulfochlorinated and sulfonamide derivatives of n-tetradecane by gas chromatography/mass spectrometry

The photosulfochlorination of n-tetradecane by sulfuryl chloride leads to a reaction mixture containing unreacted n-tetradecane, chloro n-tetradecanes and n-tetradecanesulfonyl chlorides. Direct and simultaneousGCanalysis of the mixture of the sulfochlorinated and chlorinated isomers is followed by mass spectrometry identification of all the components either by electron impact (EI-MS) and by negative and positive chemical ionisation (NCI-MS and PCI-MS). With the goal of performing an accurate quantitative GC analysis, and as n-tetradecanesulfonyl chlorides prone to degrade partially into the corresponding chlorides, the former are converted to N,N-diethylsufonamides, more stable thermally, and then analysed by GC/EI-MS and GC/PCI-MS. The chloro n-tetradecanes, sulfonylchlorides and sulfonamides spectra present strong similarities. However, some differences between terminal and internal isomers are noticed and the peculiar behaviour of sulfonamides is emphasized

Synthesis and antibacterial activity of benzo[4,5]isothiazolo[2,3-a]pyrazine-6,6-dioxide derivatives

Using a routine procedure, a number of derivatives of the benzo[4,5]isothiazolo[2,3-a]pyrazine-6,6-dioxide ring system have been synthesized from readily available starting materials. A series of chalcones were synthesized, which were subsequently reacted with chlorosulfonic acid to generate chalcone sulfonyl chlorides. The chalcone sulfonyl chlorides were then treated with bromine to generate dibromo chalcone sulfonyl chlorides. These were subsequently reacted with 1,2-diaminopropane and 2-methyl-1,2-diaminopropane in boiling ethanol resulting in compounds 2–10 and 11–19 respectively, in 12–80% yields. The products were characterized by spectral analysis and the definitive structure of compound 11 was determined by X-ray crystallography. The synthesized compounds were screened for potential antibacterial properties against Bacillus subtilis, Escherichia coli, Proteus vulgaris and Staphylococcus aureus

CuI catalyzed sulfonylation of organozinc reagents with sulfonyl halides

In this study, a facile CuI catalyzed synthesis of sulfones involving a nucleophilic addition of functionalized organozinc reagents to organic sulfonyl chlorides is realized. This reaction proceeds efficiently at room temperature, giving rise to various functional group substituted sulfones, generally in moderate to high yields. The method provides a novel, simple, and promising strategy for functionalized sulfone synthesis in the research field of sulfur chemistry

New Synthetic Approaches to Alk-1-enyl Sulfones and Sulfoxides

This thesis is devoted to the finding of new synthetic approaches to alk-1-enyl sulfones and sulfoxides. In particular, uncomplexed organoaluminum reagents reacted with aluminium sulfinates to afford alkenyl sulfoxides in good yields (72-75%). Sulfonyl chlorides reacted with pyridine-complexed alanes in the presence of PPh3 to afford sulfoxides in up to 94% yields; a reasonable mechanism is proposed. Sulfinyl chlorides react with alkynyl aluminium reagents to give alkynyl sulfoxides in modest yields (43-57%). Pyridine-complexed organoalanes react with sulfonyl chlorides in the presence of Ph3PO to give alkenyl sulfones in good yields (75%). Uncomplexed organoalanes reacted with pyridine-sulfonyl chloride complexes to afford sulfones in variable yields (40-90%). Finally, N-acyl-2-alkenyl-2H-dihydropyridine and dihydroisoquinoline derivatives are obtained via reaction of organoalane-pyridine complexes with acid halides

Correlation of the Rates of Solvolysis of Two Arenesulfonyl Chlorides and of trans-β-Styrenesulfonyl Chloride – Precursors in the Development of New Pharmaceuticals

Additional specific rates of solvolysis have been determined, mainly in fluoroalcohol containing solvents, for benzenesulfonyl chloride (1) and p-nitrobenzene-sulfonyl chloride (2). For trans-β-styrenesulfonyl chloride (3), a study has been carried out in 43 pure and binary solvents, covering a wide range of hyroxylic solvent systems. For the specific rates of solvolyses of each of the three substrates, a good correlation was obtained over the full range of solvents when the extended Grunwald-Winstein equation was applied. The sensitivities to changes in solvent nucleophilicity and solvent ionizing power are similar to values determined earlier and an SN2 process is proposed. For 3, kinetic solvent isotope effects of 1.46 for kH2O/kD2O and 1.76 for kMeOH/kMeOD were determined. These are also compared to literature values for other sulfonyl chlorides

Synthesis and Antimicrobial Activity of 1,2-Benzothiazine Derivatives

© 2016 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).A number of 1,2-benzothiazines have been synthesized in a three-step process. Nine chalcones 1-9 bearing methyl, fluoro, chloro and bromo substituents were chlorosulfonated with chlorosulfonic acid to generate the chalcone sulfonyl chlorides 10-18. These were converted to the dibromo compounds 19-27 through reaction with bromine in glacial acetic acid. Compounds 19-27 were reacted with ammonia, methylamine, ethylamine, aniline and benzylamine to generate a library of forty-five 1,2-benzothiazines 28-72. Compounds 28-72 were evaluated for their antimicrobial activity using broth micro dilution techniques against two Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus), and two Gram-negative bacteria (Proteus vulgaris and Salmonella typhimurium). The results demonstrated that none of the compounds showed any activity against Gram-negative bacteria, P. vulgaris and S. typhimurium, however compounds 31, 33, 38, 43, 45, 50, 53, 55, 58, 60, 63 and 68 showed activity against Gram-positive bacteria, Bacillus subtilis and Staphylococcous aureus. The range of MIC and MBC was 25-600µg/ml; though some of the MIC and MBC concentrations were high indicating weak activity. Structure activity relationship studies revealed that the compounds with a hydrogen atom or an ethyl group on the nitrogen of the thiazine ring exerted antibacterial activity against Gram-positive bacteria. The results also showed that the compounds where the benzene ring of the benzoyl moiety contained a methyl group or chlorine or bromine atom in the para position showed higher antimicrobial activity. Similar influences were identified where either a bromine or chlorine atom was in the meta position.Peer reviewedFinal Published versio

Synthesis and Antimicrobial Activity of 1,2-Benzothiazine Derivatives

A number of 1,2-benzothiazines have been synthesized in a three-step process. Nine chalcones 1–9 bearing methyl, fluoro, chloro and bromo substituents were chlorosulfonated with chlorosulfonic acid to generate the chalcone sulfonyl chlorides 10–18. These were converted to the dibromo compounds 19–27 through reaction with bromine in glacial acetic acid. Compounds 19–27 were reacted with ammonia, methylamine, ethylamine, aniline and benzylamine to generate a library of 45 1,2-benzothiazines 28–72. Compounds 28–72 were evaluated for their antimicrobial activity using broth microdilution techniques against two Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) and two Gram-negative bacteria (Proteus vulgaris and Salmonella typhimurium). The results demonstrated that none of the compounds showed any activity against Gram-negative bacteria P. vulgaris and S. typhimurium; however, compounds 31, 33, 38, 43, 45, 50, 53, 55, 58, 60, 63 and 68 showed activity against Gram-positive bacteria Bacillus subtilis and Staphylococcous aureus. The range of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was 25–600 µg/mL, though some of the MIC and MBC concentrations were high, indicating weak activity. Structure activity relationship studies revealed that the compounds with a hydrogen atom or an ethyl group on the nitrogen of the thiazine ring exerted antibacterial activity against Gram-positive bacteria. The results also showed that the compounds where the benzene ring of the benzoyl moiety contained a methyl group or a chlorine or bromine atom in the para position showed higher antimicrobial activity. Similar influences were identified where either a bromine or chlorine atom was in the meta position

Синтез та деякі перетворення 5-ізоксазолілсульфонілхлоридів

The effect of the structure of 5-(benzylthio)isoxazoles on selectivity of the synthesis of 5-(chlorosulfonyl)isoxazoles has been determined. The chemical behavior in relation to amines has been described.Aim. To develop the methods for the synthesis of 5-(chlorosulfonyl)- isoxazoles and 4-chloro-5-(chlorosulfonyl)isoxazoles as promising reagents for construction of prospective bioactive compounds.Results and discussion. The number of 5-(benzylthio)isoxazoles was obtained by cyclocondensation of N-hydroxyimidoyl chlorides or 2-chloro-2-(hydroxyimino) acetates with benzylethynylsulfide. Their oxidative chlorination with gaseous chlorine led to formation of the mixture of isoxazole-5-sulfonyl chlorides and 4-chloroisoxazole-5-sulfonyl chlorides. The ratio between these products in the mixture depended on the nature of the substitution group in position 3 of the isoxazole ring. For the synthesis of 4-chloro-5-(chlorosulfonyl)isoxazoles with acceptable yields the approach of an advance chlorination of 5-benzylthioisoxazoles by N-chlorosuccinimide with further oxidative chlorination was used.Experimental part. The synthesis of the starting and target compounds was performed in classic preparative conditions; flesh-chromatography; elemental analysis; LCMS; 1H and 13C NMR-spectroscopy were used.Conclusions. The reaction of oxidative chlorination of 5-(benzylthio)-3-isoxazoles has been studied. The synthetic approach for the previously unknown representatives of isoxazole-5-sulfonylchlorides has been developed.Определено влияние структуры 5-бензилтиоизоксазолов на селективность образования 5-изоксазолилсульфонилхлоридов и выявлено химическое поведение последних по отношению к аминам.Цель  работы – создание методов синтеза 5-изоксазолил- и 4-хлор-5-изоксазолилсульфонилхлоридов как перспективных реагентов для конструирования потенциально биоактивных веществ.Результаты и их обсуждение. Циклоконденсацией N-гидроксиимидоилхлоридов или 2-хлоро-2-(гидроксиимино)ацетатов из бензилтиоацетиленом синтезировано ряд 5-бензилтиоизоксазолов. Их окислительное хлорирование приводит к образованию смеси 5-изоксазолилсульфонилхлоридов и 4-хлор-5-изоксазолилсульфонилхлоридов, соотношение между которыми зависит от характера заместителей в положении 3 изоксазольного цикла. Для синтеза 4-хлор-5-изоксазолилсульфонилхлоридов с удовлетворительными выходами использован вариант предварительного хлорирования ядра 5-бензилтиоизоксазолов N-хлорсукцинимидом с дальнейшим окислительным хлорированием.Экспериментальная часть. Синтез исходных и целевых соединений в классических препаративных условиях; методы флеш-хроматографии, элементного анализа, хроматомасс-спектрометрии, ЯМР 1Н и 13С-спектроскопии. Выводы. Исследована реакция окислительного хлорирования 5-бензилтиоизоксазолов и разработан синтетический подход к ранее неизвестным представителям 5-изоксазолилсульфонилхлоридов.Встановлено вплив структури 5-бензилтіоізоксазолів на селективність утворення 5-ізоксазолілсульфонілхлоридів та з’ясована хімічна поведінка останніх по відношенню до амінів.Мета роботи – створення методів синтезу 5-ізоксазоліл- та 4-хлоро-5-ізоксазолілсульфонілхлоридів як перспективних реагентів для конструювання потенційно біоактивних речовин.Результати та їх обговорення. Циклоконденсацією N-гідроксіімідоїлхлоридів або 2-хлоро-2-(гідроксііміно)ацетатів із бензилтіоацетиленом синтезовано низку 5-бензилтіоізоксазолів. Їх окиснювальне хлорування приводить до утворення суміші 5-ізоксазолілсульфонілхлоридів та 4-хлоро-5-ізоксазолілсульфонілхлоридів, співвідношення між якими залежить від характеру замісників у положенні 3 ізоксазольного циклу. Для синтезу 4-хлоро-5-ізоксазолілсульфонілхлоридів із задовільними виходами використано варіант попереднього хлорування ядра 5-бензилтіоізоксазолів N-хлоросукцинімідом із подальшим окиснювальним хлоруванням.Експериментальна частина. Синтез вихідних та цільових сполук у класичних препаративних умовах; методи флеш-хроматографії, елементного аналізу, хроматомас-спектрометрії, ЯМР 1Н та 13С-спектроскопії.Висновки. Досліджена реакція окиснювального хлорування 5-бензилтіоізоксазолів та розроблено синтетичний підхід до раніше невідомих представників 5-ізоксазолілсульфонілхлоридів

[18F]Tosyl fluoride as a versatile [18F]fluoride source for the preparation of 18F-labeled radiopharmaceuticals

Positron emission tomography (PET) is an in vivo imaging technology that utilizes positron-emitting radioisotope-labeled compounds as PET radiotracers that are commonly used in clinic and in various research areas, including oncology, cardiology, and neurology. Fluorine-18 is the most widely used PET-radionuclide and commonly produced by proton bombardment o

Coumarins as Fluorescent Labels of Biomolecules

Important areas such as environmental sciences, medicine, pharmacy, and cellular biology are dependent on very sensitive analytical techniques. One of the most common methodologies used for their bioanalytical purposes is the fluorescent labelling. The synthesis of new fluorophores and the great development of fluorescent-labelling techniques combined with the enormous technological advances in the field of fluorescence microscopy allowed to deepen the structural knowledge of biomolecules. This new organic fluorophores form covalent bonds with the sample to be analyzed, producing stable bioconjugates that show fluorescence in a wide range of wavelengths, depending on the label used. Coumarin derivatives represent one of the most important chemical classes of organic fluorescent materials being one of the most extensively investigated and commercially significant groups of organic fluorescent materials. In this chapter, it is reviewed the use of fluorescent coumarin derivatives and their application to labelling biomolecules. These fluorescent labels allow researchers to study, and understand, biomolecular assemblies that exhibit complex sensitivity and selectivity. Reactive fluorescent coumarin derivatives are actually widely used in labelling biomolecules as peptides, proteins, oligonucleotides, nucleic acids, and carbohydrates, among other biological molecules