4300-35-0Relevant academic research and scientific papers
Halogen-substituted ureas for anion binding: solid state and solution studies
Casula, Arianna,Fornasier, Marco,Montis, Riccardo,Bettoschi, Alexandre,Argent, Stephen P.,Blake, Alexander J.,Lippolis, Vito,Marongiu, Laura,Picci, Giacomo,Tidey, Jeremiah P.,Caltagirone, Claudia
, p. 875 - 886 (2017/10/07)
Herein, we report the synthesis and the anion binding properties of a family of N,N′-diphenylureas L1-L15, bearing on the aromatic ring(s) halogens (chlorine and iodine) and/or nitro or trifluoromethyl electron-withdrawing groups. The analysis of the crystal structures obtained from single crystal X-ray diffraction experiments shows that self-assembled chains or tapes connected via N–H···O hydrogen bonds are the most commonly adopted arrangements for this type of molecules in the crystal lattice. In the presence of anion guests or solvent molecules with competing hydrogen bond donors and acceptors, other supramolecular arrangements can be observed. Solution studies conducted in DMSO-d6/0.5% H2O by means of 1H-NMR titrations show the formation of 1:1 adducts with all receptors. The different observed affinities of the receptors for the anion guests were rationalised in terms of steric hindrance of the substituents on the phenyl rings and their electron-withdrawing properties.
Ortho-substituent effects on diphenylurea packing motifs
Solomos, Marina A.,Watts, Taylor A.,Swift, Jennifer A.
, p. 5065 - 5072 (2018/03/01)
Hydrogen bonding between urea groups is a widely used motif in crystal engineering and supramolecular chemistry studies. In an effort to discern how the steric and electronic properties of substituents affect the molecular conformation and crystal packing
Polystyrene anchored ruthenium(II) complex catalyzed carbonylation of nitrobenzene and amines for the synthesis of disubstituted ureas
Islam, Sk Manirul,Ghosh, Kajari,Roy, Anupam Singha,Molla, Rostam Ali,Salam, Noor,Chatterjee, Tanmay,Iqubal, Md. Asif
, p. 152 - 160 (2015/01/09)
The catalytically active complex [Ru(PS-imd)(CO)2Cl2] (PS-imd = polystyrene anchored imidazole) was synthesized and characterized using various spectroscopic techniques. The complex is well characterized and highly stable. The catalytic activity of the resulting species was investigated towards the synthesis of diphenyl urea and other disubstituted ureas. The experiments were carried out under high CO pressure, high temperature condition in mild coordinating media. The catalyst was found to produce excellent yields with high product selectivity. Variable yields are obtained depending on the substituent on nitrobenzene and aniline. The effects of co-solvent and co-catalyst were also studied. The catalyst was very stable and could be reused for more than five times without any noticeable loss of its catalytic activity.
Polystyrene anchored ruthenium(II) complex catalyzed carbonylation of nitrobenzene and amines for the synthesis of disubstituted ureas
Islam, Sk Manirul,Ghosh, Kajari,Roy, Anupam Singha,Molla, Rostam Ali,Salam, Noor,Chatterjee, Tanmay,Iqubal, Md. Asif
, p. 152 - 160 (2015/01/30)
The catalytically active complex [Ru(PS-imd)(CO)2Cl2] (PS-imd = polystyrene anchored imidazole) was synthesized and characterized using various spectroscopic techniques. The complex is well characterized and highly stable. The catalytic activity of the resulting species was investigated towards the synthesis of diphenyl urea and other disubstituted ureas. The experiments were carried out under high CO pressure, high temperature condition in mild coordinating media. The catalyst was found to produce excellent yields with high product selectivity. Variable yields are obtained depending on the substituent on nitrobenzene and aniline. The effects of co-solvent and co-catalyst were also studied. The catalyst was very stable and could be reused for more than five times without any noticeable loss of its catalytic activity.
Friedel-Crafts-type reactions with ureas and thioureas
Raja, Erum K.,Nilsson Lill, Sten O.,Klumpp, Douglas A.
supporting information; experimental part, p. 8141 - 8143 (2012/09/07)
Despite the relatively low reactivities of urea and thiourea functional groups towards nucleophilic attack, we have found conditions in which they are useful substrates in Friedel-Crafts reactions. The Bronsted superacid, triflic acid, promotes these reactions and a mechanism is proposed involving dicationic, superelectrophilic intermediates.
2-substituted imidazoquinoxaline diones, a new class of GABA brain receptor ligands
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, (2008/06/13)
The invention encompasses compounds of the formula: STR1 and the pharmaceutically acceptable non-toxic salts thereof wherein R1, R2, R3, and R4 represent organic or inorganic substituents; X represents hydrogen,
N- and O-Alkylations of Nitro-Substituted 1,3-Diphenylureas: Preparations of Propellant Stabilizer Derivatives
Curtis, Neville J.
, p. 585 - 595 (2007/10/02)
A procedure has been developed for the N-ethylation and methylation of 1,3-diphenylureas, ArNRCONHAr' (R=H, Me or Et), through treatment with sodium hydride and iodoalkane in dimethylformamide.The reaction was general, provided that the aniline to be alkylated was substituted with no more than one nitro group.ArRNCONR'Ar' derivatives prepared were: R = R'= Et (and Me); Ar = phenyl, Ar' = 2-nitrophenyl and 4-nitrophenyl; Ar = 2-nitrophenyl, Ar' = 2-nitrophenyl and 4-nitrophenyl; Ar = Ar' = 4-nitrophenyl.Two mixed derivatives were also prepared: R = Et, R' = Me, Ar = phenyl, Ar' = 2-nitrophenyl and 4-nitrophenyl.O-Alkylated isourea products were obtained in the reactions of 1-(2,4-dinitrophenyl)-3-(2-nitrophenyl)urea and 1-(2,4-dinitrophenyl)-3-(4-nitrophenyl)urea.The use of potassium carbonate as the base led to apparently exclusive O-alkylation of 1,3-bis(2-nitrophenyl)urea although the reaction was not general. 1-(2,4-Dinitrophenyl)-1,3-diethyl-3-phenylurea was prepared by using silver oxide and obtained as a mixture with the isourea.Many of the compounds prepared are important nitro derivatives of the propellant stabilizers, ethyl and methyl centralite.
Intramolecular Reaction Between Nitro and Carbodi-imide Groups; A New Synthesis of 2-Arylbenzotriazoles
Houghton, Peter G.,Pipe, David F.,Rees, Charles W.
, p. 1471 - 1480 (2007/10/02)
1-(2-Nitrophenyl)-5-phenyltetrazole (5b) decomposes when heated to give nitrogen, carbon dioxide, and 2-phenylbenzotriazole (6) in high yield.This new molecular rearrangement proceeds via 2-nitrophenyl(phenyl)carbodi-imide (8).Other precursors of this carbodi-imide, i.e. oxadiazolone (10), oxadiazolethione (11), oxathiadiazole 2-oxide (12), and the aminimide (16), and carbodi-imide itself, all give 2-phenylbenzotriazole (6) on thermolysis, the last three in high yield.This reaction is general for diarylcarbodi-imides with an ortho nitro group, and their precursors, and it provides a useful new route to 2-arylbenzotriazoles.A sequence of electrocyclic ring closing and opening reactions (Scheme 5) is proposed as the mechanism of this process.The key intermediate, 2-phenyl-1,2,4-benzotriazin-3-one 1-oxide (19) has been isolated from a careful thermolysis of (12) in toluene; in solution it is in reversible equlibrium with the ring-opened form (20).This new nitro-carbodi-imide group interaction has been extended to the more stable nitrobiphenyl(phenyl)carbodi-imide (25) and nitronaphthyl(phenyl)carbodi-imide (24) which, on flash vacuum pyrolysis, give benzimidazophenanthridine (29) and benzindazole 1-oxide (32) respectively, in new rearrangements.
