- Chromatography-Free Multicomponent Synthesis of Thioureas Enabled by Aqueous Solution of Elemental Sulfur
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The development of a new three-component chromatography-free reaction of isocyanides, amines and elemental sulfur allowed us the straightforward synthesis of thioureas in water. Considering a large pool of organic and inorganic bases, we first optimized the preparation of aqueous polysulfide solution from elemental sulfur. Using polysulfide solution, we were able to omit the otherwise mandatory chromatography, and to isolate the crystalline products directly from the reaction mixture by a simple filtration, retaining the sulfur in the solution phase. A wide range of thioureas synthesized in this way confirmed the reasonable substrate and functional group tolerance of our protocol.
- Németh, András Gy.,Szabó, Renáta,Domján, Attila,Keser?, Gy?rgy M.,ábrányi-Balogh, Péter
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- Synthesis, characterization, and pharmacological evaluation of thiourea derivatives
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Thioureas and their derivatives are organosulfur compounds having applications in numerous fields such as organic synthesis and pharmaceutical industries. Symmetric thiourea derivatives were synthesized by the reaction of various anilines with CS2. The synthesized compounds were characterized using the UV-visible and nuclear magnetic resonance (NMR) spectroscopic techniques. The compounds were screened for in vitro inhibition of α-amylase, α-glucosidase, acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE) enzymes and for their antibacterial and antioxidant potentials. These compounds were fed to Swiss male albino mice to evaluate their toxicological effects and potential to inhibit glucose-6-phosphatase (G6Pase) inhibition. The antibacterial studies revealed that compound 4 was more active against the selected bacterial strains. Compound 1 was more active against 2,2-diphenyl-1-picrylhydrazyl and 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radicals, AChE, BuChE, and α-glucosidase. Compound 2 was more potent against α-amylase and G6Pase. Toxicity studies showed that compound 4 is safe as it exerted no toxic effect on any of the hematological and biochemical parameters or on liver histology of the experimental animals at any studied dose rate. The synthesized compounds showed promising antibacterial and antioxidant potential and were very active (both in vitro and in vivo) against G6Pase and moderately active against the other selected enzymes used in this study.
- Alghamdi, Saad,Naz, Sumaira,Sahibzada, Muhammad Umar Khayam,Ulbari, Wasim,Umar, Muhammad Naveed,Zahoor, Muhammad
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p. 764 - 777
(2020/07/20)
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- An efficient and recyclable thiourea-supported copper(i) chloride catalyst for azide-alkyne cycloaddition reactions
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A reaction between two equivalents of bulky thiourea, i.e., 1,3-bis(2,6-dimethylphenyl)thiourea (L) [L = (ArNH)2C = S; Ar = 2,6-Me2C6H3], and CuCl2 or CuCl in THF solvent afforded a bulky thiourea-sta
- Barman, Milan Kr.,Sinha, Ashish Kumar,Nembenna, Sharanappa
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p. 2534 - 2541
(2016/05/19)
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- Efficient synthesis of aluminium-terminated polyethylene by means of irreversible coordinative chain-transfer polymerisation using a guanidinatotitanium catalyst
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A series of guanidinato-ligand-stabilised titanium complexes has been synthesised and characterised. These compounds can be prepared by carbodiimide insertion into titanium-amide bonds. Reaction of carbodiimides N,N′-bis(2,6-diisopropylphenyl)carbodiimide, N,N′-bis(2,6- dimethylphenyl)carbodiimide and N-tert-butyl-N′-(2,6-diisopropylphenyl) carbodiimide (2a-2c, respectively) with [(Et2N)TiCl3] led to mono(guanidinato)trichloridotitanium(IV) complexes (3a-3c). Subsequent conversion with methylmagnesium chloride gave the corresponding trimethyl complexes (4a and 4b). Single-crystal X-ray diffraction analyses were carried out for all complexes. Compound 4a showed very high activities in the polymerisation of ethylene in the presence of very high amounts of triethylaluminium and undergoes polymeryl chain transfer to aluminium. Irreversible coordinative chain-transfer polymerisation and a unique combination of catalyst economy and high activity were observed. In the presence of 1000 equivalents of aluminium, a chain elongation of 83.3 % could be achieved with an activity of 9900 kgPE molcat-1 h-1 bar-1. The influence of the steric demand of the ligand on the polymerisation capability is significant and was investigated too. A series of novel mono(guanidinato)titanium(IV) complexes has been synthesised and characterised. Single-crystal analyses were performed for all complexes. Compound 4a showed very high activities in the polymerisation of ethylene in the presence of very high amounts of aluminium after activation with fluorinated borates. Irreversible coordinative chain transfer to aluminium was observed. Copyright
- Obenauf, Johannes,Kretschmer, Winfried P.,Kempe, Rhett
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p. 1446 - 1453
(2014/04/03)
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- Efficient synthesis of aluminium-terminated polyethylene by means of irreversible coordinative chain-transfer polymerisation using a guanidinatotitanium catalyst
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A series of guanidinato-ligand-stabilised titanium complexes has been synthesised and characterised. These compounds can be prepared by carbodiimide insertion into titanium-amide bonds. Reaction of carbodiimides N,N′-bis(2,6-diisopropylphenyl)carbodiimide, N,N′-bis(2,6-dimethylphenyl)carbodiimide and N-tert-butyl-N′-(2,6-diisopropylphenyl)carbodiimide (2a-2c, respectively) with [(Et2N)TiCl3] led to mono(guanidinato)trichloridotitanium(IV) complexes (3a-3c). Subsequent conversion with methylmagnesium chloride gave the corresponding trimethyl complexes (4a and 4b). Single-crystal X-ray diffraction analyses were carried out for all complexes. Compound 4a showed very high activities in the polymerisation of ethylene in the presence of very high amounts of triethylaluminium and undergoes polymeryl chain transfer to aluminium. Irreversible coordinative chain-transfer polymerisation and a unique combination of catalyst economy and high activity were observed. In the presence of 1000 equivalents of aluminium, a chain elongation of 83.3 % could be achieved with an activity of 9900 kgPE molcat-1 h-1 bar-1. The influence of the steric demand of the ligand on the polymerisation capability is significant and was investigated too. A series of novel mono(guanidinato)titanium(IV) complexes has been synthesised and characterised. Single-crystal analyses were performed for all complexes. Compound 4a showed very high activities in the polymerisation of ethylene in the presence of very high amounts of aluminium after activation with fluorinated borates. Irreversible coordinative chain transfer to aluminium was observed.
- Obenauf, Johannes,Kretschmer, Winfried P.,Kempe, Rhett
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p. 1446 - 1453
(2015/04/27)
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- Synthesis of thioureas in ionic liquid medium
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A highly efficient procedure for the synthesis of symmetrical thioureas by means of simple condensation of primary amines and carbon disulfide in 1-butyl-3-methylimidazolium chloride [BMIM][Cl] as a cheap and commercially available ionic liquid is presented. This procedure works for aromatic and aliphatic primary amines and give high to excellent yields of symmetrical thioureas without need for any catalyst or tedious work-up.
- Halimehjani, Azim Ziyaei,Farahbakhsh, Fataneh
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p. 284 - 288
(2013/08/26)
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- Synthesis and conformational features of sym N,N′,N″- triarylguanidines
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A one pot reaction involving sym N,N′-diarylthiourea and the respective arylamine in the presence of aq. KOH in nitrobenzene at ≥105°C afforded sym N,N′,N″-triarylguanidine in fair to good yield and the products have been characterized. Sym N,N′,N″-tri(4-tolyl)guanidine possesses (7) anti-anti conformation, sym N,N′,N″-tri(2-tolyl) guanidine (8) and sym N,N′,N″-tris(2,4-xylyl)guanidine (11) each possess anti-anti αβα conformation whereas sym N,N′,N″-tris(2-anisyl)guanidine possesses (9) syn-anti αββ conformation as determined by single crystal X-ray diffraction data. The observed conformations appear to result from a subtle balance between steric factor associated with the aryl substituent and multiple electronic factors namely n-π conjugation/negative hyperconjugation and non-covalent interactions in the crystal lattice. Indian Academy of Sciences.
- Gopi, Kanniyappan,Rathi, Brijesh,Thirupathi, Natesan
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experimental part
p. 157 - 167
(2010/11/17)
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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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