2080-59-3Relevant academic research and scientific papers
Reinvestigation of o-phenylenediamine thermal cyclocondensation with thiosemicarbazide
Bakavoli,Rezaei Seresht,Rahimizadeh
, p. 273 - 274 (2006)
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.
Synthesis and crystal structures of benzimidazole-2-thione derivatives by alkylation reactions
El Ashry, El Sayed H.,Kilany, Yeldez El,Nahas, Nariman M.,Barakat, Assem,Al-Qurashi, Nadia,Ghabbour, Hazem A.,Fun, Hoong-Kun
, (2016)
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.
Ball milling assisted solvent and catalyst free synthesis of benzimidazoles and their derivatives
El-Sayed, Taghreed H.,Aboelnaga, Asmaa,Hagar, Mohamed
, (2016)
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.
Slow, spontaneous degradation of lansoprazole, omeprazole and pantoprazole tablets: Isolation and structural characterization of the toxic antioxidants 3H-benzimidazole-2-thiones
Rajab,Touma,Rudler,Afonso,Seuleiman
, p. 749 - 754 (2013)
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.
A new strategy for the synthesis of 2-mercaptobenzazole derivatives by green chemistry metrics
Vessally, Esmail,Monfared, Aazam,Eskandari, Zahra,Abdoli, Morteza,Hosseinian, Akram
supporting information, p. 1 - 5 (2020/08/25)
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.
Synthesis of thiocarbamoyl fluorides and isothiocyanates using amines with CF3SO2Cl
Jiang, Lvqi,Yi, Wenbin,Wei, Jingjing,Liang, Shuaishuai
, p. 12374 - 12381 (2020/11/10)
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.
One-step construction of unsymmetrical thioureas and oxazolidinethiones from amines and carbon disulfide: Via a cascade reaction sequence
Ding, Chaochao,Wang, Shaoli,Sheng, Yaoguang,Dai, Qian,Zhao, Yunjie,Liang, Guang,Song, Zengqiang
, p. 26768 - 26772 (2019/09/06)
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.
Synthesis Of di- and tri-substituted thiourea derivatives in water using choline chloride–urea catalyst
Tavakol, Hossein,Mahmoudi, Amir,Ranjbari, Mohammad-Amin
, p. 113 - 123 (2018/10/24)
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.
Pyridinethiol-Assisted Dissolution of Elemental Gold in Organic Solutions
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
supporting information, p. 17104 - 17109 (2018/12/04)
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.
AlCl3-Promoted Synthesis of 2-Mercapto Benzoheterocycles by Using Sodium Dimethyldithiocarbamate as Thiocarbonyl Surrogate
Liu, Xing,Zhang, Shi-Bo,Dong, Zhi-Bing
, p. 5406 - 5411 (2018/10/20)
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.
