- A green, isocyanide-based three-component reaction approach for the synthesis of multisubstituted ureas and thioureas
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A one-pot, isocyanide based multicomponent protocol was presented starting from secondary amines towards (thio)urea derivatives and utilized for the construction of a diverse 27-membered chemical library. Following a green compatible microwave assisted condition, the formed N,N′-multisubstituted (thio)ureas were obtained in up to 85% yield.
- Angyal, Anikó,Demjén, András,W?lfling, János,Puskás, László G.,Kanizsai, Iván
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Read Online
- An isocyanide based multi-component reaction under catalyst- and solvent-free conditions for the synthesis of unsymmetrical thioureas
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A new and efficient method for the synthesis of thiourea derivatives by a sequential one-pot, three-component reaction between aromatic isocyanides, amines, and 1,2-di-tert-butyldisulfane (DTBS) was developed and 27 different examples were synthesized in good to excellent yields. DTBS was identified as an effective sulfur surrogate without the use of both catalysts and solvents. This protocol does not employ any transition metal catalyst or special experimental setup.
- Singh, Karandeep,Sharma, Siddharth
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p. 197 - 201
(2016/12/28)
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- Eosin y catalyzed visible-light-promoted aerobic oxidative cyclization of 2-aminobenzothiazole
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A mild and efficient one-pot visible light irradiated synthesis of 2-aminobenzothiazole 4(a-l) from arylisothiocyanate 1(a-l) and secondary amines 2 have been reported in presence of eosin Y as an organophotoredox catalyst at room temperature under aerobi
- Srivastava, Vishal,Singh, Pravin K.,Singh, Praveen P.
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p. 227 - 233
(2016/01/20)
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- A ligand free copper(II) catalyst is as effective as a ligand assisted Pd(II) catalyst towards intramolecular C-S bond formation via C-H functionalization
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Copper(I) catalysts are usually ineffective on the other hand Pd(II) catalysts are quite effective in promoting intramolecular sp2 C-H functionalization (C-S bond formation). Herein, we have developed a ligand assisted Pd(II) catalyzed C-S bond formation via C-H activation from arylthioureas leading to the formation of 2-aminobenzothiazoles for substrates bearing electron donating (EDG) groups in the aryl ring. However without the assistance of ligand this Pd(II) catalyzed reaction is quite unproductive particularly for thioureas possessing strongly electron donating groups in the aryl rings. Interestingly, the ligand free Cu(II) catalyzed oxidative cyclization of arylthioureas are equally effective both for arylthioureas possessing electron donating as well as electron withdrawing groups in the aryl rings.
- Banerjee, Arghya,Santra, Sourav Kumar,Rout, Saroj Kumar,Patel, Bhisma K.
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p. 9096 - 9104
(2013/09/24)
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- A model for a solvent-free synthetic organic research laboratory: Click-mechanosynthesis and structural characterization of thioureas without bulk solvents
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The mechanochemical click coupling of isothiocyanates and amines has been used as a model reaction to demonstrate that the concept of a solvent-free research laboratory, which eliminates the use of bulk solvents for either chemical synthesis or structural characterization, is applicable to the synthesis of small organic molecules. Whereas the click coupling is achieved in high yields by simple manual grinding of reactants, the use of an electrical, digitally controllable laboratory mill provides a rapid, quantitative and general route to symmetrical and non-symmetrical aromatic or aromatic-aliphatic thioureas. The enhanced efficiency of electrical ball milling techniques, neat grinding or liquid-assisted grinding, over manual mortar-and-pestle synthesis is demonstrated in the synthesis of 49 different thiourea derivatives. Comparison of powder X-ray diffraction data of mechanochemical products with structural information found in the Cambridge Structural Database (CSD), or obtained herein through single crystal X-ray diffraction, indicates that the mechanochemically obtained thiourea derivatives are pure in a chemical sense, but can also demonstrate purity in a supramolecular sense, i.e. in all structurally explored cases the product consisted of a single polymorph. As an extension of our previous work on solvent-free synthesis of coordination polymers, it is now demonstrated that such polymorphic and chemical purity of selected thiourea derivatives, the latter being evidenced through quantitative reaction yields, can enable the direct solvent-free structural characterization of mechanochemical products through powder X-ray diffraction aided by solid-state NMR spectroscopy.
- Strukil, Vjekoslav,Igrc, Marina D.,Fabian, Laszlo,Eckert-Maksic, Mirjana,Childs, Scott L.,Reid, David G.,Duer, Melinda J.,Halasz, Ivan,Mottillo, Cristina,Friscic, Tomislav
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supporting information
p. 2462 - 2473
(2013/02/21)
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- Heterocycle formation via palladium-catalyzed intramolecular oxidative C-H bond functionalization: An efficient strategy for the synthesis of 2-aminobenzothiazoles
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N-Arylthioureas are converted to 2-aminobenzothiazoles via Intramolecular C-S bond formation/C-H functionalization utilizing an unusual cocatalytic Pd(PPh3)4MnO2 system under an oxygen atmosphere at 80 °C. This method elim
- Joyce, Laurie L.,Batey, Robert A.
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supporting information; experimental part
p. 2792 - 2795
(2009/11/30)
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- Highly efficient and catalyst-free synthesis of unsymmetrical thioureas under solvent-free conditions
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A highly efficient and simple synthesis of unsymmetrical thioureas is reported based on the reaction of readily synthesized dithiocarbamates with amines, without using any catalyst under solvent-free conditions. The short reaction time, high yields, and s
- Halimehjani, Azim Ziyaei,Pourshojaei, Yaghoub,Saidi, Mohammad R.
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scheme or table
p. 32 - 34
(2009/04/10)
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- 1-(Alkyl/Arylthiocarbamoyl)benzotriazoles as Stable Isothiocyanate Equivalents: Synthesis of Di- and Trisubstituted Thioureas
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1-(Alkyl/arylthiocarbamoyl)benzotriazoles 4a-i were synthesized in yields of 91-99% from bis(benzotriazolyl)methanethione (3). Reagents 4a-g were then used as isothiocyanate equivalents for the efficient synthesis of 10 secondary and 14 tertiary thioureas
- Katritzky, Alan R.,Ledoux, Stephane,Witek, Rachel M.,Nair, Satheesh K.
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p. 2976 - 2982
(2007/10/03)
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- Oxidation of thiocarbamyls with lead tetraacetate
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Oxidation of a series of arylthiocarbamyls 2 to the corresponding bis-formamidinomonosulphides 3 with lead tetraacetate has been carried out. In addition sulphur is obtained.
- Chattree, N. S.,Chandel, M. S.,Sharma, T. C.
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p. 1178 - 1180
(2007/10/03)
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- Fragmentation of N-aryl- and N-Aralkyl-N',N"-dicarbomethoxyguanidines with Thiophosgene
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N-Aryl- and N-aralkyl-N',N"-dicarbomethoxyguanidines (3) on treatment with thiophosgene undergo fragmentation to yield N,N'-dicarbomethoxyurea (5) and the isothiocyanates.
- Viswanathan, N.,Sidhaye, A. R.
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p. 659 - 660
(2007/10/02)
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