- Micelle-Enabled One-Pot Guanidine Synthesis in Water Directly from Isothiocyanate using Hypervalent Iodine(III) Reagents under Mild Conditions
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In this work, we developed a one-pot synthesis of guanidine directly from isothiocyanate using DIB (diacetoxyiodobenzene) as a desulfurizing agent under micellar conditions in water. Our optimization study revealed that the use of 1 % TPGS-750-M as a surfactant with NaOH as an additive base at room temperature can convert a variety of isothiocyanates and amines into corresponding guanidines in excellent yields (69–95 %). This synthetic process in water can be applied to prepare guanidine at gram-scale quantity. Our aqueous micellar medium also demonstrated high reusability as the reaction can be performed for several cycles without losing its efficiency. The reaction is metal-free, utilizes water as solvent and practical (room temperature and open flask).
- Srisa, Jakkrit,Tankam, Theeranon,Sukwattanasinitt, Mongkol,Wacharasindhu, Sumrit
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p. 3335 - 3343
(2019/09/12)
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- Ph3P/I2-mediated synthesis of N,N′,N″-substituted guanidines and 2-iminoimidazolin-4-ones from aryl isothiocyanates
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A convenient one-pot procedure for the synthesis of acyclic and cyclic guanidines mediated by the Ph3P/I2 system is described. Sequential condensation of aryl isothiocyanates with amines followed by dehydrosulfurization and guanylation could lead to both symmetric and unsymmetric N,N′,N″-substituted derivatives. Through a tandem guanylation-cyclization, a series of 2-iminoimidazolin-4-ones could also be prepared in good yields from the reaction of aryl isothiocyanates with amino acid methyl esters.
- Wangngae, Sirilak,Pattarawarapan, Mookda,Phakhodee, Wong
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p. 10331 - 10340
(2018/05/31)
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- Synthesis and characterisation of [(en)2Co]3+ complexes coordinated by substituted thiourea ligands
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Substituted thiourea ligands bind in a bidentate manner forming a four-membered ring through the sulfur atom and a deprotonated thiourea nitrogen atom when reacted with [(en)2Co(OSO2CF3)2]+ in tetramethylene sulfone. Reaction of unsymmetrical ligands results in the formation of coordination isomers, some of which can be separated by column chromatography using Sephadex SPC-25. Coordination isomers are easily distinguishable based on visible and 1H NMR spectroscopy . Twelve para-substituted and one meta-substituted ligands were studied: N,N′-dibenzylthiourea (1a); N-(R)phenyl-N′-benzylthiourea R≤H (2a), NO2 (2b), CH3 (2c); N-(R)phenyl-N′-(R′)phenylthiourea R, R′: H, H (3a), H, CH3 (3b), OCH3, NO2 (3c), CH3, NO2 (3d); N-methyl-N′-(R)phenylthiourea R≤H (4a), CH3 (4b), OCH3 (4c), NO2 (4d), 3-CH3 (4e). The solid state structure (X-ray) of one isomer of Co-4a as its perchlorate salt confirms the coordination mode suggested by 1H NMR spectroscopy and shows that the Co-N bond trans to the coordinated thiourea sulfur induces a structural trans effect of 0.019A.
- Roecker, Lee,Aiyegbo, Mohammed,Al-Haddad, Aladdin,Fletcher, Emily,Kc, Ravi,Hurst, Jason,Lane, Timothy,Larsen, Ryan,Noinaj, Nicholas,Teh, Say Lee,Wade, Samuel K.,Parkin, Sean
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p. 944 - 951
(2013/09/12)
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- A simple and green procedure for the synthesis of N-benzylthioureas
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A simple and efficient reaction protocol for the synthesis of N-benzylthioureas is described from benzylisothiocyanate (BITC: 94% pure/GC-MS), isolated from crushed papaya seeds.
- De Sequeira Aguiar, Lucia C.,Viana, Gil M.,Dos Santos Romualdo, Marcus V.,Costa, Marcio V.,Bonato, Bruno S.
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experimental part
p. 540 - 544
(2012/06/01)
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