Structure and reactivity of benzothiazole-2-thione polysulfides

A quantum-chemical study was made of the possibility of the formation of polysulfides from benzothiazole-2-thione and their structure. The reactivity indices of the benzothiazole-2-thione molecule and of the small sulfur fragments were calculated. It was shown that as the fragments approach each other the formation of polysulfide structures with increased reactivity becomes possible.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 26, No. 1, pp. 73–78, January–February, 1990.     

Photocycloaddition of Benzothiazole-2-thiones to Alkenes

The photocycloaddition of benzothiazole-2-thiones to electron-rich and aryl-substituted alkenes are described. Irradiation of N-unsubstituted benzothiazole-2-thione ( 1 ) in the presence of alkenes 3 gave 2-(2′-mercaptoalkyl)benzothiazoles 4 , and 2-substituted benzothiazoles 5 and 6 (in the case of 3a and 3h , resp.) through the ring cleavage of an intermediate 2-aminothietane (Schemes 1 and 3 ). The latter was formed by [2+2] cycloaddition of the C?S bond of 1 and the C?C bond of 3 . Irradiation of N-methylbenzothiazole-2-thione ( 2 ) and 2-methylpropene ( 3a ) gave the spiro-1,3-dithiane 8 , 1,2,6-benzodithiazocin-5-one 9 , and disulfide 10 . The structure of 9 was established by X-ray crystal-structure analysis.     

14N nuclear quadrupole coupling in cyclic amides and thioamides. Ab initio simulations of the solid state environment as interpretation of the NQR spectra of 2-pyridinone,isatin and benzothiazole-2-one. A new x-ray structure for isatin

A new determination of the X-ray structure of isatin is reported. Ab initio SCF calculations of the local crystal environment in 2-pyridinone (a trimeric structure) and each of isatin and benzothiazole-2-one (dimeric structures) are reported. In view of the importance of the NH bond lengths in the bicyclic compounds, these were treated as variables in the computations, and found to be relatively short (1.01 Å). In all three molecules χ_zz lies out of plane both in the monomeric and dimer and trimer calculations but in the last two types a reduction in magnitude of χ_zz occurs.     

Raman spectroscopic and density functional theory studies on a benzothiazole-2-thione derivative

The two tautomers of 7H-[1,3]dioxolo[4′,5′,4,5]benzo[1,2-d]thiazole-6-thione (DBTT) have been investigated by FT-IR and FT-Raman combined with density functional theory (DFT) calculations at the B3LYP level and 6-311+G** basis sets. On the basis of optimized structures, the harmonic force fields, vibrational frequencies and Raman intensities were calculated and scaled. The assignment of the fundamental vibrations for this molecule in its thione form was performed according to the potential energy distribution (PED) analysis. We have also discussed the adsorption behavior of DBTT on gold by means of SERS and DFT calculations at the same level. It revealed that the DBTT exhibited stable conformation of benzothiazole-2-thione (BTT) form both in solid and on gold surfaces; in addition, DBTT molecule is chemisorbed to the gold through both N and the exocyclic S atoms in its thione form and its molecular plane is perpendicular to the surface as BTT. The results show that the substituted groups in the phenyl ring have changed the characters such as the charge density in heterocyclic atoms and so on, but have little influence on the tautomeric preference of the BTT molecule and adsorption orientation on gold.     

Group 6 metal carbonyl complexes of 3′H-spiro[indole-3,2′-[1,3]benzothiazole-2(1H)]-one

The spiro-compound 3′H-spiro[indole-3,2′-[1,3]benzothiazole-2(1H)-one (IBTH₂) was synthesized and its structure was determined using spectroscopic techniques (FTIR, ¹H NMR and mass) and X-ray crystallography. This ligand possesses different centers for coordination. Reactions of [M(CO)₆], M = Cr, Mo or W with IBTH₂ in THF under reduced pressure were studied. For chromium a complex with molecular formula [Cr(ITP)₂] was isolated; where ITP is the opened form of the ligand which occurred through C_spiro–S bond, while [Mo(CO)₅(IBTH₂)] and [W(CO)₅(IBTH₂)] were isolated from the reaction of IBTH₂ with molybdenum and tungsten carbonyls, respectively. All complexes were characterized by elemental analysis, IR, mass and ¹H NMR spectroscopy. The biological activity of the ligand and its complexes were studied and compared with the parent compound isatin.     

Synthesis of 4,5-dihydrothiazole derivatives by the reaction of perfluoro-2-methylpent-2-en-3-yl isothiocyanate with ambident N,O- and N,S-nucleophiles

The reactions of perfluoro-2-methylpent-2-en-3-yl isothiocyanate with ambident N,O- and N,S-nucleophiles (thiazole-2-thione, pyridine-2-thione, 2-hydroxypyridine, benzothiazole-2-thione, benzoxazole-2-thione, 3,4,5,6-tetrahydropyrimidine-2-thione) in the presence of triethylamine yield only 2-N-substituted 4,5-dihydrothiazole derivatives. The molecular structures of three products were determined by X-ray diffraction analysis. The reaction pathways are discussed.     

Hydrogen bonding abilities and self-association of thiazolidin-and imidazolidin-2-ones and 2-selenones

The hydrogen bonding abilities of iV-methylimidazolidin-2-one and -2-selone and thiazolidin-2-one and -2-selenone have been studied by ir spectroscopy at 25° in carbon tetrachloride solutions, using dimethyl sulphoxide and 4-chlorophenol as proton acceptor (K_A) and proton donor (K_B), respectively. The results are compared with those previously reported for N-methylimidazolidine-2-thione and thiazolidine-2-thione. The K_A values increase in each series in the order O < S < Se and Kg in the reverse order. The and K_B values are discussed in terms of the substituent in ring. The self-association constants (K_D) are dependent on both K_A and K_B, although K_A seems to be much more important.     

Syntheses on the basis of 2H-chromen-2-one and 2H-chromene-2-thione

4-Hydroxy-2H-chromen-2-one and 4-hydroxy-2H-chromene-2-thione reacted with allyl bromide, 1,1,3-trichloroprop-1-ene, and 1,3-dichlorobut-2-ene to give the corresponding ethers, which were oxidized to (2-oxo-2H-chromen-4-yloxy)acetic acid with potassium permanganate, and various derivatives of that acid were obtained. 3-(3,3-Dichloroprop-2-enyl)-7-hydroxy-4-methyl-2H-chromen-2-one and 3-(3,3-dichloroprop-2-enyl)-7-hydroxy-4-methyl-2H-chromene-2-thione were synthesized, and some their transformations were studied.     

Synthesis and biological evaluation of novel benzothiazole-2-thiol derivatives as potential anticancer agents

A series of novel benzothiazole-2-thiol derivatives were synthesized and their structures determined by 1H-NMR, 13C-NMR and HRMS (ESI). The effects of all compounds on a panel of different types of human cancer cell lines were investigated. Among them, pyridinyl-2-amine linked benzothiazole-2-thiol compounds 7d, 7e, 7f and 7i exhibited potent and broad-spectrum inhibitory activities. Compound 7e displayed the most potent anticancer activity on SKRB-3 (IC(50) = 1.2 nM), SW620 (IC(50) = 4.3 nM), A549 (IC(50) = 44 nM) and HepG2 (IC(50) = 48 nM) and was found to induce apoptosis in HepG2 cancer cells.     

Synthesis of 3-Aryl[1,2,4]triazolo[3,4-<Emphasis Type="Italic">b</Emphasis>][1,3]benzothiazole-6,7-dicarbonitriles from 5-Aryl-4H-triazole-2-thiols and 5-Bromo-5-nitrophthalonitrile

New 3-aryl-substituted [1,2,4]triazolo][3,4-b][1,3]benzothiazole-6,7-dicarbonitriles have been synthesized by successive interaction of 5-aryl-4H-triazole-2-thiols with 4-bromo-5-nitrophthalonitrile in the presence of K₂CO₃ initially at the bromine atoms and then at the nitro group.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, 270–272, February, 2005.     

2-Trif luoromethyl-4H-thiochromen-4-one and 2-trif luoromethyl-4H-thiochromene-4-thione: Synthesis and reactivities

2-Trifluoromethyl-4H-thiochromene-4-thione obtained from 2-trifluoromethyl-4H-thiochromen-4-one and P₂S₅ reacts with aromatic amines, hydrazine hydrate, phenylhydrazine, and hydroxylamine at the C(4) atom of the chromene ring to give the corresponding anils, azine, hydrazones, and oxime of thiochromone. 2-Trifluoromethyl-4H-thiochromen-4-one is oxidized by hydrogen peroxide in AcOH into 4-oxo-2-trifluoromethyl-4H-thiochromene 1,1-dioxide and reduced by NaBH₄ to 2-trifluoromethyl-4H-thiochromen-4-ol or cis-2-(trifluoromethyl)thiochroman-4-ol. When treated with hydrazine hydrate, thiochromen-4-one gives 3(5)-(2-mercaptophenyl)-5(3)-trifluoromethylpyrazole. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 504–509, March, 2006.     

Simple Method for the Preparation of 1,3-Dithiol-2-one and 1,3-Dithiol-2-thione

Abstract

The reaction of diisopropyl xanthogen and thio-diisopropyl xanthogen disulfide with alkynes furnished 1,3-dithiol-2-one and 1,3-dithiol-2-thione.     

Cyanoacetylenes in a reaction with benzoxazole-2-thione and benzoxazol-2-one

The reaction of benzoxazole-2-thione and benzoxazol-2-one with substituted cyanoacetylenes was studied. 2-[(3-Phenyl-2-propenenitrile)thio]benzoxazole was obtained by the reaction of benzoxazole-2-thione with phenylcyanoacetylene. Benzoxazol-2-one with phenylcyanoacetylene and a tertiary cyanoacetylenic alcohol gave the corresponding N-adducts.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1390–1391, June, 1990.     

Reaction of <Emphasis Type="Italic">N</Emphasis>-aryl-3-oxobutanethioamides with 2-amino-1,3-thiazole and 2-amino-1,3-benzothiazole

N-Aryl-3-oxobutanethioamides react with 2-amino-1,3-thiazole (2-amino-1,3-benzothiazole) in acetic acid to give mixtures of 7-methyl-5H-[1,3]thiazolo[3,2-a]pyrimidine-5-thione (2-methyl-4H-pyrimido-[2,1-b][1,3]benzothiazole-4-thione) and 5-arylimino-7-methyl-5H-[1,3]thiazolo[3,2-a]pyrimidines (4-arylimino-2-methyl-4H-pyrimido[2,1-b][1,3]benzothiazoles), whose ratio depends on the nature of the aryl substituent in the initial butanethioamide.     

The Rearrangement of 2—Benzothiazolylthioacetyl Hydrazide in Synthesis of s—Triazolo[3,4—b]benzothiazole—3—thiol

The rearrangement reaction of 2-benzothiazolylthioacetyl hydrazide 1 with potassium hydroxide and carbon disulfide in ethanol to produce s-triazolo [3,4-b] benzothiazole-3-thiol 3 was described. 3 also can be obtained from 2-benzothiazolylhydazine 2 and the two methods for getting 3 were compared. Mannich reaction of compounds 3 was reported too.     

What Is Its Real Existing Form? ---Theoretical and Experimental Studies on 2-Mercaptobenzothiazole

The geometry of 2-mercaptobenzothiazole (MBT) and its tautomeric form of benzo- thiazole-2-thione are optimized at B3LYP/6-311G** and HF/6-311G** levels, respectively. The crystal structure of benzothiazole-2-thione and its FTIR spectra are also obtained. From the calcu- lated and experimental data, it can be concluded that in gas-phase and solid-state, the real existing form of 2-mercaptobenzothiazole is the thione-form of MBT.     

PHOTOCHEMISTRY OF 2-MERCAFTOPYRIDINES. PART 2. AN EPR AND SPIN-TRAPPING INVESTIGATION USING 2-METHYL-2-NITROSOPROPANE AND aci-NITROMETHANE AS SPIN TRAPS IN AQUEOUS SOLUTIONS*

Abstract Compounds possessing a pyridine-2-thione moiety show antimicrobial, antifungal and anticancer activities. Some of them are also photochemically active and upon UV irradiation generate free radicals. In this work, employing EPR and the spin traps 2-methyl-2-nitrosopropane (MNP) and aci-nitromethane (NM), we investigated the photochemistry in aqueous solutions of N-hydroxypyridine-2-thione (used here as a sodium salt, 2-S-PyrNONa), and pyridine-2-thione (2-S-PryH), as well as photochemistry of the respective disulfides, 2,2′-dithiobis(pyridine N-oxide) [(2-S-PyrN→O)₂] and 2,2′-dithiodipyridine [(2-S-Pyr)₂]. We found that UV irradiation of 2-S-PyrNONa and of 2-S-PyrH in the presence of MNP and NM generates EPR signals of reduced spin traps in addition to signals of MNP and NM adducts with aryl-thiyl radicals, 2–.S-PyrN→O and 2–.S-Pyr. The identification of the aromatic thiyl radicals was based on comparison of EPR spectra of spin adducts generated by irradiation of 2-S-PyrNONa and 2-S-PyrH with those produced by UV photolysis of the respective disulfides (2-S-PyrN→O), and (2-S-Pyr)₂. It is concluded that pyridine-2-thione and N-hydroxypyridine-2-thione possess a photoreducing capacity and generate aromatic thiyl radicals upon UV activation. This property may be relevant to biological action of agents containing the pyridine-2-thione moiety.     

Synthesis of some sulfur-containing pyrido[1,2-α]pyrimidines

4-Methylthiopyrido[1,2-α]pyrimidin-2-one and 2-hydroxypyrido[1,2-α]pyrimidine-4-thione derivatives were synthesized by the addition ofN-(4-R-pyrid-2-yl)acetoacetamides (R = H, Me) to CS₂ under phase-transfer conditions followed by the alkylation of the reaction products with Mel. The molecular structure of 3-acetyl-4-methylthiopyrido[1,2-α]pyrimidin-2-one is established by X-ray analysis.     

1,3-Heterazolidines-2-heterounsaturated compounds derived from ephedrines

Herein, a direct and easy method for preparing 2-oxo-, 2-thione- or 2-imine-1,3-heterazolidines derived from ephedrines and norephedrines are reported. The method is based on solvent free heating of ephedrines with oxocyanate or thiocyanate salts (180–200 °C). In the reactions with potassium oxocyanate in refluxing ethanol, it was possible to isolate ureidic derivatives. The structure and stereochemistry of the compounds were determined by ¹H, ¹³C NMR, IR spectroscopies and mass spectrometry. Ureidic derivatives, cis-1,5-dimethyl-4-phenyl-imidazolidine-2-thione and trans-4-methyl-5-phenyl-thiazolidine-2-one are new compounds. Ephedrineurea, cis-1,5-dimethyl-4-phenyl-imidazolidine-2-thione and trans-4-methyl-5-phenyl-thiazolidine-2-one were also studied by X-ray diffraction.     

What Is Its Real Existing Form?——Theoretical and Experimental Studies on 2-Mercaptobenzothiazole

1 INTRODUCTION The study of heterocyclic molecules with aroma- tic rings and their absorptions on metals is of con- siderable importance from both theoretical and te- chnological points of view. These molecules are in- teresting because of their applications as corrosion inhibitors and flotation collectors, and their abilities to form self-assembly layers[1]. 2-Mercaptobenzo- thiazole (C7H5NS2, in the following MBT) is an important heterocyclic molecule, which can be used as corrosion …