- A new strategy for the synthesis of 2-mercaptobenzazole derivatives by green chemistry metrics
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A green and efficient method has been developed for the synthesis of 2-mercaptobenzazole derivatives via the reaction of commercially available aniline derivatives with low-cost and nontoxic potassium thiocyanate in water. The reactions proceeded smoothly under catalyst- and ligand-free conditions to give the corresponding products in good to excellent yields. The versatility, low cost, and environmental friendliness, in combination with high yields and easy work-up makes the procedure noteworthy.
- Vessally, Esmail,Monfared, Aazam,Eskandari, Zahra,Abdoli, Morteza,Hosseinian, Akram
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supporting information
p. 1 - 5
(2020/08/25)
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- Synthesis of thiocarbamoyl fluorides and isothiocyanates using amines with CF3SO2Cl
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A practical and efficient method to synthesize thiocarbamyl fluorides and isothiocyanates from amines with trifluoromethanesulfonyl chloride was developed. In the presence of the reducing agent triphenylphosphine and sodium iodide, thiocarbamyl fluorides and isothiocyanates were synthesized from secondary/primary amine in moderate to excellent yields, respectively. A broad scope of substrates and good functional group compatibility were observed.
- Jiang, Lvqi,Yi, Wenbin,Wei, Jingjing,Liang, Shuaishuai
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p. 12374 - 12381
(2020/11/10)
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- One-step construction of unsymmetrical thioureas and oxazolidinethiones from amines and carbon disulfide: Via a cascade reaction sequence
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A concise and versatile method for the construction of unsymmetrical thioureas and oxazolidinethiones from amines and carbon disulfide has been achieved in DMSO without addition of extra reagents. The present protocol is compatible with various secondary amines and primary amines, and suitable for intermolecular and intramolecular reactions. Diverse unsymmetrical thioureas and oxazolidinethiones were efficiently obtained in good to excellent yields via a cascade reaction sequence.
- Ding, Chaochao,Wang, Shaoli,Sheng, Yaoguang,Dai, Qian,Zhao, Yunjie,Liang, Guang,Song, Zengqiang
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p. 26768 - 26772
(2019/09/06)
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- Synthesis Of di- and tri-substituted thiourea derivatives in water using choline chloride–urea catalyst
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In this work, di- and tri-substituted thiourea derivatives have been synthesized via a one-pot, three-component reaction from carbon disulfide and aliphatic or aromatic amines using choline chloride-urea deep eutectic solvent as a catalyst in water. Both cyclic and acyclic thiourea derivatives with two or three substituents were synthesized successfully. The reactions were done at 25–100°C, using 5–20 mol% catalyst, in 3–5 h and the GC-Mass yields were between 60% and 95%. All products were characterized using FT-IR, 1H-NMR, 13C-NMR, GC-MS and melting point analyses. The results showed that both water and the DES have important effects on the yield and the rate of this reaction and both of them are necessary to obtain higher yields in less time. The extra experiment, which was designed to study the mechanism of the reaction, showed that an isothiocyanate intermediate was formed in the reaction. Finally, the results showed that by the increase of the amine's nucleophilicity, the reaction occurs faster and gives higher yield.
- Tavakol, Hossein,Mahmoudi, Amir,Ranjbari, Mohammad-Amin
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p. 113 - 123
(2018/10/24)
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- Pyridinethiol-Assisted Dissolution of Elemental Gold in Organic Solutions
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Dissolution of elemental gold in organic solutions is a contemporary approach to lower the environmental burden associated with gold recycling. Herein, we describe fundamental studies on a highly efficient method for the dissolution of elemental Au that is based on DMF solutions containing pyridine-4-thiol (4-PSH) as a reactive ligand and hydrogen peroxide as an oxidant. Dissolution of Au proceeds through several elementary steps: isomerization of 4-PSH to pyridine-4-thione (4-PS), coordination with Au0, and then oxidation of the Au0 thione species to AuI simultaneously with oxidation of free pyridine thione to elemental sulfur and further to sulfuric acid. The final dissolution product is a AuI complex bearing two 4-PS ligands and SO42? as a counterion. The ligand is crucial as it assists the oxidation process and stabilizes and solubilizes the formed Au cations.
- R?is?nen, Minna,Heli?vaara, Eeva,Al-Qaisi, Feda'a,Muuronen, Mikko,Eronen, Aleksi,Liljeqvist, Henri,Nieger, Martin,Kemell, Marianna,Moslova, Karina,H?m?l?inen, Jani,Lagerblom, Kalle,Repo, Timo
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supporting information
p. 17104 - 17109
(2018/12/04)
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- AlCl3-Promoted Synthesis of 2-Mercapto Benzoheterocycles by Using Sodium Dimethyldithiocarbamate as Thiocarbonyl Surrogate
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A simple, expeditious and high-efficiency synthetic method for the AlCl3-mediated one-pot preparation of 2-mercapto benzoheterocycles (2-mercapto benzothiazoles, benzoxazoles and benzimidazoles) is described. By the treatment of a series of S, O and N heteroatoms containing bifunctional molecules with sodium dimethyldithiocarbamate in AlCl3, the desired benzoheterocycles are obtained smoothly. The protocol can also be applied on the synthesis of a series of thiazolidine-2-thiones, imidazolidine-2-thiones. This novel synthetic approach has advantages such as ligand-free, high efficiency, short reaction time, readily available starting materials and simple experimental procedures.
- Liu, Xing,Zhang, Shi-Bo,Dong, Zhi-Bing
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p. 5406 - 5411
(2018/10/20)
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- A catalyst-free and additive-free method for the synthesis of benzothiazolethiones from: O -iodoanilines, DMSO and potassium sulfide
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Under catalyst-free and additive-free conditions, a novel, convenient, eco-friendly method for the synthesis of benzothiazolethiones has been developed. The three-component reaction of o-iodoanilines and K2S with DMSO proceeded smoothly and the corresponding benzothiazolethiones were obtained with good isolated yields. Meanwhile, this method could be used for the synthesis of thioureas from primary diamines. Furthermore, mechanism research showed that DMSO not only functioned as a carbon source, but also as a mild oxidant in this reaction.
- Zhu, Xiaoming,Li, Wenguang,Luo, Xiai,Deng, Guobo,Liang, Yun,Liu, Jianbing
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supporting information
p. 1970 - 1974
(2018/05/23)
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- Thiocarbonyl Surrogate via Combination of Sulfur and Chloroform for Thiocarbamide and Oxazolidinethione Construction
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An efficient and practical thiocarbonyl surrogate via combination of sulfur and chloroform has been developed. A variety of thiocarbamides and oxazolidinethiones have been established, including chiral thiourea catalysts and chiral oxazolidinethione auxiliaries with high selectivity. Meanwhile, pesticides Diafenthiuron (an acaricide), ANTU (a rodenticide), and Chloromethiuron (an insecticide) were practically synthesized through this method in gram scale. Dicholorocarbene, as the key intermediate, was further confirmed via a carbene-trapping control experiment.
- Tan, Wei,Wei, Jianpeng,Jiang, Xuefeng
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supporting information
p. 2166 - 2169
(2017/04/27)
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- Reaction of Thiocarbonyl Fluoride Generated from Difluorocarbene with Amines
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The reaction of thiocarbonyl fluoride, generated from difluorocarbene, with various amines under mild conditions is described. Secondary amines, primary amines, and o-phenylenediamines are converted to thiocarbamoyl fluorides, isothiocyanates, and difluoromethylthiolated heterocycles, respectively. Thiocarbamoyl fluorides were further transformed into trifluoromethylated amines by using a one-pot process. Thiocarbonyl fluoride is generated in situ and is rapidly fully converted in one pot under mild conditions; therefore, no special safety precautions are needed.
- Yu, Jiao,Lin, Jin-Hong,Xiao, Ji-Chang
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supporting information
p. 16669 - 16673
(2017/12/07)
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- An environmentally benign and efficient synthesis of substituted benzothiazole-2-thiols, benzoxazole-2-thiols, and benzimidazoline-2-thiones in water
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An efficient and practical method for the one-step synthesis of benzothiazole-2-thiols, benzoxazole-2-thiols and benzimidazoline-2-thiones by cyclization of 2-aminothiophenols, 2-aminophenols, and 1,2-phenylenediamines with tetramethylthiuram disulfide (TMTD) in water was described. The features of this method include metal/ligand-free, excellent yield, short reaction time and broad substrate scope. The method provides a facile and convenient preparation of some potentially biologically active compounds.
- Liu, Xing,Liu, Min,Xu, Wan,Zeng, Meng-Tian,Zhu, Hui,Chang, Cai-Zhu,Dong, Zhi-Bing
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p. 5591 - 5598
(2017/12/06)
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- Thiosemicarbazide Derivatives as Building Block in Synthesis of Target Heterocyclic Compounds with Their Antimicrobial Assessment
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1-(2-Benzamido-3-(1,3-diphenyl-1H-pyrazol-4-yl)acryloyl)-4-phenylthiosemicarbazide is used as precursor for synthesis of imidazole, 1,3,4-oxadiazole, 1,3,4-thiadiazole, 1,3-oxazine, and 1,2,4-triazine ring systems. The antimicrobial activity of some of th
- Abou Elmagd, Wael S. I.,Hemdan, Magdy M.,Samy, Sandy S.,Youssef, Ahmed S. A.
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p. 1391 - 1395
(2017/03/27)
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- Ball milling assisted solvent and catalyst free synthesis of benzimidazoles and their derivatives
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Benzoic acid and o-phenylenediamine efficiently reacted under the green solvent-free Ball Milling method. Several reaction parameters were investigated such as rotation frequency; milling balls weight and milling time. The optimum reaction condition was milling with 56.6 g weight of balls at 20 Hz frequency for one hour milling time. The study was extended for synthesis of a series of benzimidazol-2-one or benzimidazol-2-thione using different aldehydes; carboxylic acids; urea; thiourea or ammonium thiocyanate with o-phenylenediamine. Moreover; the alkylation of benzimidazolone or benzimidazolthione using ethyl chloroacetate was also studied.
- El-Sayed, Taghreed H.,Aboelnaga, Asmaa,Hagar, Mohamed
-
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- Synthesis and crystal structures of benzimidazole-2-thione derivatives by alkylation reactions
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Alkylated, benzylated and bromoalkylated benzimidazole-thione that intramolecularly heterocyclized to 3,4-dihydro-2H-[1,3]thiazino[3,2-a]benzimidazole were synthesized. The chemical structure of the synthesized product was characterized by Infra Red, 1H-NMR, 13C-NMR, and Mass spectroscopy. Furthermore, the molecular structures of 8 and 9 were confirmed by X-ray single crystallography in different space groups, Pbca and P21/c, respectively.
- El Ashry, El Sayed H.,Kilany, Yeldez El,Nahas, Nariman M.,Barakat, Assem,Al-Qurashi, Nadia,Ghabbour, Hazem A.,Fun, Hoong-Kun
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- Alkylation and Aminomethylation of 1,3-Dihydro-2H-Benzimidazole-2-Thione
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Alkylation of 1,3-dihydro-2H-benzimidazole-2-thione (2-mercaptobenzimidazole) with bromoethane and chloroacetic acid derivatives occurrs at the sulfur atom, leading to the corresponding 2-sulfanylbenz-imidazole derivatives. Aminomethylation of 1,3-dihydro-2H-benzimidazole-2-thione with piperidine and 4-methylpiperidine gives reaction products at both nitrogen atoms, while reaction with morpholine gives derivative at only one nitrogen atom, which is in an equilibrium with the starting compound and bis-adduct in DMSO solution.
- Bespalov,Gorchakova,Ivanov,Kuznetsov,Kuznetsova,Pankova,Prokopenko,Avdontceva
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p. 1547 - 1558
(2015/02/19)
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- Lanthanide-catalyzed cyclocarbonylation and cyclothiocarbonylation: A facile synthesis of benzannulated 1,3-diheteroatom five- and six-membered heterocycles
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La[N(SiMe3)2]3 proves to be an efficient catalyst system for the cyclocarbonylation of 1,2-disubstituted benzenes with isocyanates. In this approach, aryl/alkyl isocyanates react with o-phenylenediamine, o-aminophenol, o-aminothiophenol, catechols and anilines ortho-substituted by CH2NH2 and CONH2 to form, respectively, the corresponding benzimidazolones, benzoxazolones, benzothiazolones, benzodioxolones, 3,4-dihydroquinazolin-2(1H)-one, and quinazolinediones. These results represent the first example of lanthanide-catalyzed carbonylation. This methodology is also applicable for the preparation of various benzannulated 1,3-diheteroatom cyclic thioketones starting from aryl/alkyl isothiocyanates or CS2 in good to excellent yields. Based on the results of experiments performed using an o-aminobenzamido dianion lanthanide complex, a general mechanism, involving the tandem reaction of two lanthanide-ligand bonds with one heterocumulene molecule, is proposed as well.
- Jing, Yufeng,Liu, Ruiting,Lin, Yanghui,Zhou, Xigeng
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p. 1117 - 1125
(2014/08/18)
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- Imidazopyridine- and purine-thioacetamide derivatives: Potent inhibitors of nucleotide pyrophosphatase/phosphodiesterase 1 (NPP1)
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Nucleotide pyrophosphatase/phosphodiesterase 1 (NPP1) belongs to the family of ecto-nucleotidases, which control extracellular nucleotide, nucleoside, and (di)phosphate levels. To study the (patho)physiological roles of NPP1 potent and selective inhibitors with drug-like properties are required. Therefore, a compound library was screened for NPP1 inhibitors using a colorimetric assay with p-nitrophenyl 5′-thymidine monophosphate (p-Nph-5′-TMP) as an artificial substrate. This led to the discovery of 2-(3H-imidazo[4,5-b]pyridin-2-ylthio)-N-(3,4-dimethoxyphenyl)acetamide (5a) as a hit compound with a Ki value of 217 nM. Subsequent structure-activity relationship studies led to the development of purine and imidazo[4,5-b]pyridine analogues with high inhibitory potency (Ki values of 5.00 nM and 29.6 nM, respectively) when assayed with p-Nph-5′-TMP as a substrate. Surprisingly, the compounds were significantly less potent when tested versus ATP as a substrate, with Ki values in the low micromolar range. A prototypic inhibitor was investigated for its mechanism of inhibition and found to be competitive versus both substrates.
- Chang, Lei,Lee, Sang-Yong,Leonczak, Piotr,Rozenski, Jef,De Jonghe, Steven,Hanck, Theodor,Müller, Christa E.,Herdewijn, Piet
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p. 10080 - 10100
(2015/02/05)
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- Synthesis and invitro Evaluation of West Nile Virus Protease Inhibitors Based on the 2-{6-[2-(5-Phenyl-4H-{1,2,4]triazol-3-ylsulfanyl)acetylamino]benzothiazol-2-ylsulfanyl}acetamide Scaffold
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In recent years, clinical symptoms resulting from West Nile virus (WNV) infection have worsened in severity, with an increased frequency in neuroinvasive diseases among the elderly. As there are presently no successful therapies against WNV for use in humans, continual efforts to develop new chemotherapeutics against this virus are highly desired. The viral NS2B-NS3 protease is a promising target for viral inhibition due to its importance in viral replication and its unique substrate preference. In this study, a WNV NS2B-NS3 protease inhibitor with a 2-{6-[2-(5-phenyl-4H-[1,2,4]triazol-3-ylsulfanyl)acetylamino]benzothiazol-2-ylsulfanyl}acetamide scaffold was identified during screening. Optimization of this initial hit by synthesis and screening of a focused compound library with this scaffold led to the identification of a novel uncompetitive inhibitor (1a24, IC50=3.4±0.2μM) of the WNV NS2B-NS3 protease. Molecular docking of 1a24 into the WNV protease showed that the compound interferes with productive interactions of the NS2B cofactor with the NS3 protease and is an allosteric inhibitor of the WNV NS3 protease.
- Samanta, Sanjay,Lim, Ting Liang,Lam, Yulin
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supporting information
p. 994 - 1001
(2013/07/27)
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- Regioselective synthesis of isoxazole-mercaptobenzimidazole hybrids and their in vivo analgesic and anti-inflammatory activity studies
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Regioselective synthesis of isoxazole-mercaptobenzimidazole hybrids and their efficiency in in vivo analgesic and anti-inflammatory activity was described. A comparison of structure-activity relationship for there compounds was also emphasized.
- Kankala, Shravankumar,Kankala, Ranjith Kumar,Gundepaka, Prasad,Thota, Niranjan,Nerella, Srinivas,Gangula, Mohan Rao,Guguloth, Hanmanthu,Kagga, Mukkanti,Vadde, Ravinder,Vasam, Chandra Sekhar
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p. 1306 - 1309
(2013/03/14)
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- Slow, spontaneous degradation of lansoprazole, omeprazole and pantoprazole tablets: Isolation and structural characterization of the toxic antioxidants 3H-benzimidazole-2-thiones
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The spontaneous degradation of lansoprazole, omeprazole and pantoprazole tablets upon long-term and forced storage conditions was determined by high performance liquid chromatography (HPLC). The more abundant products could be isolated by liquid chromatography and their molecular weights determined by Mass Spectrometry (MS). Their structures, established according to their spectroscopic data, were compared to those of either the literature or of authentic samples. Thus lansoprazole led mainly to a mixture of 3H-benzimidazole-2-thione (2a) and 3H-benzimidazole-2-one (2c), omeprazole mainly to a mixture of 5-methoxy-3H-benzimidazole-2-thione (1a) and 2-hydroxymethyl-3, 5-dimethyl- 4-methoxypyridine (1b), and pantoprazole, to 5-difluoromethoxy-3H-benzimidazole-2-thione (3a) and 2-hydroxymethyl-3, 4-dimethoxypyridine (3b). Although some of the degradation products had already been observed under different conditions, the detection of benzimidazole-2- thiones is unprecedented and their involvement as possible physiological, yet toxic antioxidants must be emphasized. Plausible, unified mechanisms for the formation of the different degradation products observed herein and in previous papers from the literature are suggested.
- Rajab,Touma,Rudler,Afonso,Seuleiman
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p. 749 - 754
(2013/10/08)
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- A simple route for the synthesis of symmetrical thiourea derivatives and amidinium cations by reaction between isocyanides, amines and carbon disulfide
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Reaction between primary amines and CS2 promoted by alkyl isocyanides in ethanol as solvent provides a simple and efficient route for the synthesis of symmetrical thiourea derivatives. The reaction of secondary amines with carbon disulfide and alkyl isocyanides afforded new amidinium cations in good yields.
- Anary-Abbasinejad, Mohammad,Karimi, Nadia,Mehrabi, Hossein,Ranjbar-Karimi, Reza
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p. 653 - 659
(2013/02/22)
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- Synthesis and antiviral activity of benzimidazolyl-and triazolyl-1,3,5- triazines
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A novel series of 1,3,5-triazine analogs was successfully synthesized through conjugation with benzimidazole or 1,2,4-triazole derivatives via a methylenethio linker. The new analogs were in vitro evaluated against HSV-1 in Vero cells; among these analogs, two compounds exhibited good effect in inhibiting HSV-1 replication (for compound 5p: EC50 = 3.5 μg/ml, SI = 358; for compound 5r: EC50 = 5.0 μg/ml, SI = 300) in comparison to acyclovir. Springer Science+Business Media, LLC 2011.
- Maarouf, Azza R.,Farahat, Abdelbasset A.,Selim, Khalid B.,Eisa, Hassan M.
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scheme or table
p. 703 - 710
(2012/09/22)
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- Enhanced anion binding from unusual coordination modes of bis(thiourea) ligands in platinum group metal complexes
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Treatment of a range of bis-(thiourea) ligands with inert organometallic transition-metal ions gives a number of novel complexes that exhibit unusual ligand binding modes and significantly enhanced anion binding ability. The ruthenium(II) complex [Ru(η6-p-cymene)(κS,S′,N-L 3-H)] + (2b) possesses juxtaposed four- and seven-membered chelate rings and binds anions as both 1:1 and 2:1 host guest complexes. The pyridyl bis(thiourea) complex [Ru(η6-p-cymeme)(κS,S′, Npy-L4)]2+ (4) binds anions in both 1:1 and 1:2 species, whereas the free ligand is ineffective because of intramolecular NH...N hydrogen bonding. Novel palladium(II) complexes with nine- and ten-membered chelate rings are also reported.
- Laura Soriano,Lenthall, Joseph T.,Anderson, Kirsty M.,Smith, Stephen J.,Steed, Jonathan W.
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supporting information; experimental part
p. 10818 - 10831
(2010/12/18)
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- Revisit to the reaction of o-phenylene diamine with thiosemicarbazide to give benzimidazole-2-thione rather than benzotriazine-2-thione and its glycosylation
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Reaction of o-phenylene diamine with thiosemicarbazide did not give benzotriazine-2-thione 2 as reported, although the product was found to be benzimidazole-2-thione 3. Glycosylation of 3 with acetobromo sugars 4α-4b gave the respective thioglycosides 7α-7d in addition to minor products of the nucleosides 8α and 8b, in the case of the gluco-and galacto-analogs, respectively. The regioselectivity of glycosylation reaction has been investigated. Taylor and Francis Group, LLC.
- Ashry, El Sayed H. El,Aly, Aly A.,Aouad, Mohamed R.,Amer, Mohammed R.
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experimental part
p. 698 - 706
(2011/06/21)
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- Selective benzimidazole inhibitors of the antigen receptor-mediated NF-κB activation pathway
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Dysregulated antigen receptor-mediated NF-κB activation can contribute to development of autoimmunity, chronic inflammation, and malignancy. A chemical biology screening strategy has identified a substituted benzimidazole that selectively inhibits antigen receptor-mediated NF-κB activation without blocking other NF-κB activation pathways. A library of analogs was synthesized and the structure-activity relationship and metabolic stability for the series is presented.
- Okolotowicz, Karl J.,Shi, Ranxin,Zheng, Xueying,MacDonald, Mary,Reed, John C.,Cashman, John R.
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scheme or table
p. 1918 - 1924
(2010/05/17)
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- Carbon tetrabromide promoted reaction of amines with carbon disulfide: Facile and efficient synthesis of thioureas and thiuram disulfides
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A novel carbon tetrabromide promoted one-pot reaction of amines and carbon disulfide under mild conditions has been developed, which provides a straightforward and efficient access to thioureas and thiuram disufides, depending on the nature of the amines employed. The promotion effect is explained as the transient formation of a sulfenyl bromide intermediate from dithiocarbamate and carbon tetrabromide during the reaction. Georg Thieme Verlag Stuttgart · New York.
- Liang, Fushun,Tan, Jing,Piao, Chengri,Liu, Qun
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experimental part
p. 3579 - 3584
(2009/07/04)
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- NOVEL VIRAL REPLICATION INHIBITOR
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The present invention relates to a pharmaceutical composition for the treatment or prevention of viral infections comprising as an active principle at least one benzimidazole conjugates derivative havin the general formula I. The invention also relates to processes for the preparation of compounds according to the invention having above mentioned general formula and their use as a medicine or to treat or prevent viral infections.
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-
Page/Page column 15-16
(2008/06/13)
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- Reinvestigation of o-phenylenediamine thermal cyclocondensation with thiosemicarbazide
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Thermal cyclocondensation of o-phenylenediamine with thiosemicarbazide at elevated temperature gave the 1,3-dihydro-2H-1,3-benzimidazole-2-thione not the 1,4-dihydro- 1,2,4-benzotriazine-3(2H)thione claimed by an earlier worker. Analytical and spectral data are given in support of this reinvestigtation.
- Bakavoli,Rezaei Seresht,Rahimizadeh
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p. 273 - 274
(2007/10/03)
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- Some chemical properties of 2,3-dihydro-4H-[1,3]thiazino[3,2-a] benzimidazol-4-one and 2-aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4- ones
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We have studied the reaction of 2,3-dihydro-4H-[1,3]thiazino[3,2-a] benzimidazol-4-one and 2-aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4- ones with amines, alkylating reagents, and hydrogen peroxide. We have shown that the presence of an aryl substituent at the 2 position of [1,3-thiazino[3,2-a] benzimidazol-4-ones has a substantial effect on the direction of the reactions. 2006 Springer Science+Business Media, Inc.
- Britsun,Esipenko,Lozinskii
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p. 396 - 402
(2008/02/04)
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- Thermolysis of symmetrical dithiobiurea and thioureidoethylthiourea derivatives
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Microwave and thermal heterocyclization of N,N′-disubstituted hydrazinecarbothioamide 1a,b and substituted thioureidoethylthioureas 2a-c as well as 1-phenyl-3[2-(3-phenylthio-ureido)phenyl]-thiourea 6 are reported.
- Hassan, Alaa A.,Mourad, Aboul-Fetouh E.,El-Shaieb, Kamal M.,Abou-Zied, Ashraf H.,Doepp, Dietrich
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p. 535 - 541
(2007/10/03)
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- Microwave irradiation synthesis of 2-substituted benzimidazoles using PPA as a catalyst under solvent-free conditions
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An efficient microwave irradiation synthesis of 2-substituted benzimidazoles using polyphosphoric acid (PPA) as a catalyst from organic acid and o-phenylenediamine under solvent-free conditions is described. This method is a good option to obtain the title compounds in a simple and an inexpensive way.
- Lu, Jun,Yang, Bingqin,Bai, Yinjuan
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p. 3703 - 3709
(2007/10/03)
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- Synthesis and reactions of some 3-aryl-2-thioxoquinazolin-4(3H)-ones
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A series of 3-aryl-2-thioxoquinazolin-4(3H)-ones la-g are prepared in good yields from reactions of anthranilic acids, aromatic amines and carbon disulfide under basic conditions in one step. Reaction of aminophenyl derivatives la,b with D-glucose affords the corresponding N-glucosylamines 4a,b in very good yields. Diazotization of la,b followed by reactions with aromatic amines yield the corresponding azo dyes 6a-f in 40-56% yields. The fastness for 6 has been studied. Compounds 6a,b,f have been proved to biologically active.
- El-Hiti, Gamal A.,Abdel-Megeed, Mohamed F.,Zied, Tarek M. M.
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p. 1519 - 1522
(2007/10/03)
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- 1-(Methyldithiocarbonyl)imidazole: A useful thiocarbonyl transfer reagent for synthesis of substituted thioureas
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1-(Methyldithiocarbonyl)imidazole 1 and its N-methyl quaternary salt 2 have been shown to be efficient methyldithiocarbonyl and thiocarbonyl transfer reagents for the synthesis of dithiocarbamates, symmetrical and unsymmetrical mono-, di- and tri-substituted thioureas in high yields under mild and simple non-hazardous reaction conditions. (C) 2000 Elsevier Science Ltd.
- Mohanta, Pramod K.,Dhar, Sanchita,Samal,Ila,Junjappa
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p. 629 - 637
(2007/10/03)
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- Synthesis of benzimidazoles in dry medium
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A new route to obtain 2-alkylbenzimidazoles and benzimidazol-2-one or thione is reported, using a natural clay and infrared irradiation in solvent free conditions. This method is a good option to obtain the title compounds in a simple and an inexpensive way.
- Guillermo, Penieres C.,Imelda, Bonifas A.,Jose, Guadalupe Lopez C.,Jose, Guadalupe Garcia E.,Cecilio, Alvarez T.
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p. 2191 - 2196
(2007/10/03)
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- Energy transfer, electron transfer, and addition reactions of triplet state of 1,3-dihydroimidazole-2-thiones investigated by laser flash photolysis
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The transient absorption bands observed at ca. 400 and 550 nm for 1,3- dihydro-2H-imidazole-2-thione (IT), 1,3-dihydro-1-methyl-2H-imidazole-2- thione (MIT), and 1,3-dihydro-2H-benzimidazole-2-thione (BIT) have been assigned to their triplet states (3IT* 's) by the quenching and sensitizing experiments using laser flash photolysis technique. Short intrinsic triplet lifetimes and relatively high triplet energies have been evaluated as characteristics of 3IT* 's. For electron acceptors, photoinduced electron- transfer reaction occurs via 3IT* 's in the diffusion controlled limit. The nucleophilic character of 3IT* 's was confirmed by changing the substituents of alkenes on the addition reactions. MO calculations indicate that the lowest electronic configurations of both 3IT* and 3MIT* have 3(n,π*) character, while 3BIT* has 3(π,π*) character. The addition reactivity of 3BIT* is slightly higher than those of 3IT* and 3MIT*, which is opposite to the general tendency.
- Alam, Maksudul M.,Ito, Osamu
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p. 339 - 345
(2007/10/03)
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- Synthesis of benzimidazoles in a solvent-free reaction under microwave activation
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A variety reagents (i-iii) react with o-phenylenediamine to give benzimidazoles in high yields in solvent-free reaction under microwave irradiation.
- Aghapoor, K.,Heravi, M. M.,Nooshabadi, M. A.
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- Various Syntheses of Benzimidazolin-2-ones and Benzimidazoline-2-thiones under Microwave Irradiation
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A variety of reagents (i-ix) which can be considered as carbonyl sources reacted with o-phenylenediamines to give high yields of benzimidazolin-2-ones and benzimidazoline-2-thiones on brief microwave irradiation.
- Khajavi, Mohammad S.,Hajihadi, Mostafa,Nikpour, Farzad
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- N-Hydroxymethylbenzimidazoles as formaldehyde release markers
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Extrusion of formaldehyde from different N-hydroxymethylbenzimidazoles has been observed and confirmed by chemical and thermoanalytical techniques.The applicability of this behaviour of benzimidazole N-methylols in textile industry is highlighted.
- Anklekar, Kiran Y.,Kulkarni, Manohar V.
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p. 677 - 678
(2007/10/03)
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- SYNTHESIS OF 1-AMINO-2-MERCAPTO- AND 1-AMINO-2-ALKYLTHIOBENZIMIDAZOLES
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The action of carbon disulfide on diethyl mesoxalate o-aminophenylhydrazone in pyridine gives 1-amino-2-mercaptobenzimidazole.Alkylation of the latter with alkyl halides in an alcohol solution of alkali leads to the formation of the previuosly unknown 1-amino-2-alkylbenzimidazoles, while the action of phenacyl bromides leads to 3-aryl-2H-1,3,4-thiadiazinobenzimidazoles.
- Kryshtalyuk, O. V.,Kuz'menko, V. V.,Pozharskii, A. F.
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p. 1880 - 1884
(2007/10/02)
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- A NEW ROUTE TO 1,2-DITHIOLE-3-THIONES (TRITHIONES) BY THE REACTION OF ENAMINONES WITH CARBON DISULFIDE
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Enaminones reacted with carbon disulfide in the presence of sodium hydroxide to give the corresponding 1,2-dithiole-3-thiones (trithiones) in 30-82percent yields.
- Tominaga, Yoshinori,Norisue, Hajime,Kamio, Chizuko,Masunari, Toshiyuki,Miyashiro, Yuji,Hosomi, Akira
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- Fission of 1,2,4-Thiadiazol-3-ones by Triphenylphosphane: Triphenylphosphonio Thioimidazolates and Their Consecutive Reactions
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Treatment of benzimidazothiadiazol-3(2H)-ones (1) and imidazothiadiazol-3(2H)-ones (17) with triphenylphosphan leads to the liberation of isocyanate and the formation of triphenylphosphonio-thiobenzimidazolat (4) and triphenylphosphonio-thioimidazolat (18), respectively. 2,4-Diphenyl-5-phenylimino-1,2,4-thiadiazol-3-one (23) is desulfurized with Ph3P and decomposed into phenyl isocyanate and diphenylcarbodiimide whereas the N-unsubstituted imino-thiadiazol-3-one (25) is attacked at the exocyclic imino group by Ph3P to give the N-phosphoranylidene thiourea (26).The structure of 4 can be rationalized as a dynamic system between polar and apolar valence isomeres.Reactions of 1 and 17 with cyanates, isocyanates, carbon disulfide, acetic anhydride, amines, benzyl chloride, grignard compounds, and CH acidic compounds are described.
- Tittelbach, Franz,Martin, Dieter
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p. 338 - 348
(2007/10/02)
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- Photochemistry of Pesticides, 12. On the Photoconversion of 1,3-Dihydro-2-benzimidazole-2-thione, 2(3)-Benzothiazolethione, and 2-Chlorobenzothiazole
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The photoreactivity of 1,3-dihydro-2-benzimidazole-2-thione (1a) and 2(3)-benzothiazolethione (1b) has been studied in several solvents in the presence of oxygen with or without methylene blue as a sensitizer.The corresponding disulfides (5a, b), 2-oxo derivatives (2a, b), benzimidazole and benzothiazole (11a, b), and elemental sulfur have been characterized as the main products.The UV irradiation of the disulfides 5a, b results in the formation of the same product pattern as the thiones 1a, b.Photolysis of 2-chlorobenzothiazole (12) in acetonitrile gives a mixture of 2b, 2,2'-dibenzothiazole (13), while photolysis of 12 in ethanol yields 2b and 11b.Products and mechanisms are discussed and compared with previous studies in this area. - Key words: 1,3-Dihydro-2-benzimidazole-2-thione, 2(3)-Benzothiazolethione, 2-Chlorobenzothiazole, Photodegradation, Photooxidation
- Abdou, W. M.,Sidky, M. M.,Wamhoff, H.
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p. 1153 - 1158
(2007/10/02)
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- Exchange, Elimination, and Ring Opening Reactions of 2,3-Dihydrobenzimidazothiadiazoles and 3H-Benzimidazodithiazoles
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The reactions of benzimidazothiadiazol-3(2H)-ones (1) with isocyanates, isothiocyanates, carbon disulphide, aryl cyanates, acetylenedicarboxylates, and enamines, with exchange of the isocyanate component of (1), to give the corresponding condensed benzimidazole derivatives (1)-(6) are described.Under more severe conditions the 1-benzothiazol-2-yl-1,3-dihydrobenzimidazole-2-thiones (7) were obtained from aromatic isothiocyanates.Thermolysis of the thiadiazoles (1) led to the triazine derivative (12) with elimination of isocyanate and sulphur, and in the presence of phenols to the 2-aryloxybenzimidazoles (13).With amines and CH-acidic compounds, the S,N bond in compound (1) was cleaved to give benzimidazol-2-ylsulphenamides (14), and the ω-substituted methylthiobenzimidazoles (17) and (18).With cyanide ion, insertion into the S,N bond of compound (1) to furnish the thiadiazine (22) took place.The dithiazoles (2) were fragmented by amines to give 1,3-dihydrobenzimidazole-2-thione and guanidine with loss of sulphur; reaction with cyanide ion then gave the dibenzimidazothiadiazine (25).
- Martin, Dieter,Tittelbach, Franz
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p. 1007 - 1014
(2007/10/02)
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- REACTION OF BENZIMIDAZOLE-2-THIONE WITH ACYLACETYLENES AND DIBENZOYLACETYLENE
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2-(Acylvinylthio)benzimidazoles were synthesized with good yields by the reaction of α-acetylenic ketones and dibenzoylacetylene with benzimidazole-2-thione in methanol or acetonitrile.
- Andriyankova, L. V.,Komarova, T. N.,Nakhmanovich, A. S.,Abramova, N. D.,Skvortsova, G. G.
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p. 2388 - 2390
(2007/10/02)
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- SPECTROSCOPIC AND STRUCTURAL STUDIES OF SOME BISDITHIOCARBAMATES AND CYCLIC THIONES
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The synthesis of bisdithiocarbamates from diamines and CS2 are described, and possible complications in these reactions explained.Ethylenebisdithiocarbamate was prepared from ethylendiamine and CS2 in basic solution, but the same reaction using o-phenylenediamine led to a cyclization product, o-phenyleneimidazolidine-2-thione or benzimidazolidine-2-thione.In these reactions, if slightly insufficient amounts of CS2 are used, bisdithiocarbamates will not be formed; instead, the cyclization reactions will occour, leading to the formation of thiones.Crystallographic studies were carried out for disodium ethylenebisdithiocarbamate and imidazolidine-2-thione or ethylenethiourea.The hexahydrate crystals of the former, Na2*6H2O, F.W. 364.42 are triclinic with α = 5.766(1), b = 7.212(1), c = 10.074(1)Angstroem, α = 88.53(1), β = 98.41(1), γ = 105.50(1)deg, V = 399.3(1) Angstroem3, and Z = 1.The structure was determined from 2259 unique reflections, (2065deg) to an R factor of 0.022.The bisdithiocarbamate ion has a center of symmetry between the two CH2 groups, and therefore the two NCS22- groups are separated as far apart as possible.Each Na+ ion is octahedrally surrounded by five water molecules with Na...O distances ranging from 2.373 to 2.446 Angstroem, and a sulphur atom of the thiocarbamate group with Na...S = 3.060 Angstroem.The two C-S bonds of the CS2- group are 1.710(1) and 1.727(1) Angstroem, and SCS = 121.9(1)deg.Crystals of imidazolidine-2-thione, (CH2NH2)2CS, are monoclinic, with a = 5.800(1), b = 14.516(3), c = 5.780(1) Angstroem, β = 101.33(2)deg, V = 477.2(2)Angstroem3, and Z = 4.This structure, first determined thirty years ago, has been refined by full-matrix least-squares to R = 0.031, using 975 new Mo-Kα data.
- Mak, Thomas C. W.,Jasim, Khalid S.,Chieh, Chung
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p. 808 - 813
(2007/10/02)
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- Applications of Phase Transfer Catalysis, 26. - Thioureas by Three-Component Reactions of Amines, Carbon Tetrachloride, and Sulfide Ions
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The title reactions proceed exothermically in the presence of a phase transfer catalyst.Thiophosgene is an intermediate in this conversion, and its phase transfer catalytic transformation into carbon disulfide and trithiocarbonate can be demonstrated.Perchloromethanethiol/sodium sulfide and a PT catalyst yield thiophosgene too.Activated vicinal dibromides were debrominated by Na2S/catalyst.
- Broda, Witold,Dehmlow, Eckehard V.
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p. 1839 - 1843
(2007/10/02)
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- A CONVENIENT METHOD FOR THE PREPARATION OF N,N'-DISUBSTITUTED THIOUREAS USING 2-CHLOROPYRIDINIUM SALT, SODIUM TRITHIOCARBONATE AND AMINES
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N,N'-Disubstituted thioureas were prepared in high yields by treating 2-chloropyridinium salt with sodium trithiocarbonate and subsequently adding amines.
- Takikawa, Yuji,Inoue, Noriyuki,Sato, Ryu,Takizawa, Saburo
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p. 641 - 642
(2007/10/02)
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- KINETICS OF THE ACIDIC HYDROLYSIS OF VINYL DERIVATIVES OF BENZIMIDAZOLE-2-THIONE AND BENZOXAZOL-2-ONE AND -2-THIONE
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The kinetics of the acidic hydrolysis of seven vinyl derivatives of benzimidazole-2-thione and benzoxazol-2-one and -2-thione were studied by means of polarography.The rate constants and energies of activation of the reaction were determined.The hydrolytic stabilities of the compounds depend on the nature of the heteroring and the site to which the vinyl group is attached.
- Svyatkina, L. I.,Abramova, N. D.,Dmitrieva, L. L.,Trzhtsinskaya, B. V.,Skvortsova, G. G.
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p. 1190 - 1193
(2007/10/02)
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