- Palladium-Catalyzed Aerobic Oxidative Carbonylation of Amines Enables the Synthesis of Unsymmetrical N,N′-Disubstituted Ureas
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A ligand-free palladium-catalyzed aerobic oxidative carbonylation of amines for the synthesis of ureas, particular unsymmetrically N,N′-disubstituted ureas, which cannot be accessed by any other palladium-catalyzed oxidative carbonylation of amines to date, is presented. An array of symmetrical and unsymmetrical ureas were straightforwardly synthesized by using inexpensive, readily available, stable, and safe amines with good to excellent yields under a pressure of 1 atm. This novel method employs oxygen as the sole oxidant and offers an attractive alternative to transition-metal-based oxidant systems.
- Zeng, Honglan,Du, Hongyan,Gong, Xu,Zhang, Jie,Han, Wei
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p. 1223 - 1226
(2021/06/02)
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- Direct conversion of carboxylic acids to various nitrogen-containing compounds in the one-pot exploiting curtius rearrangement
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Herein we report, a single-pot multistep conversion of inactivated carboxylic acids to various N-containing compounds using a common synthetic methodology. The developed methodology rendered the use of carboxylic acids as a direct surrogate of primary amines, for the synthesis of primary ureas, secondary/tertiary ureas, O/S-carbamates, benzoyl ureas, amides, and N-formyls, exploiting the Curtius reaction. This approach has a potential to provide a diversified library of N-containing compounds, starting from a single carboxylic acid, based on the selection of the nucleophile.
- Kumar, Arun,Kumar, Naveen,Sharma, Ritika,Bhargava, Gaurav,Mahajan, Dinesh
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p. 11323 - 11334
(2019/09/10)
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- An efficient and mild protocol for the synthesis of unsymmetrical ureas in the absence of catalyst and additives
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A new practical method for the synthesis of unsymmetrical ureas was achieved by reaction of phenylurea with primary and secondary amines under neutral and mild condition in very good yields. The reaction took place in refluxing dioxane and does not require any catalyst or additives.
- Hosseinzadeh, Rahman,Sarrafi, Yaghoub,Aghili, Nora
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experimental part
p. 1171 - 1174
(2011/10/04)
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- Copper-catalyzed arylation of phenylurea using KF/Al2O3
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A mild and efficient method for the copper-catalyzed arylation of phenylurea is described. The coupling reaction of phenylurea with different functionalized aryl iodides in the presence of air stable CuI, N,N′-dibenzylethylenediamine as a ligand, and KF/Al2O3 as a base gives symmetrical and unsymmetrical diarylureas in relatively high yields.
- Hosseinzadeh, Rahman,Sarrafi, Yaghoub,Mohadjerani, Maryam,Mohammadpourmir, Fatemeh
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p. 840 - 843
(2008/04/13)
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- DIARYL UREAS AS CB1 ANTAGONISTS
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Compounds of Formula I are provided. In which the variables are as described herein. Such compounds may be used to modulate CB1 activity in vivo or in vitro, and are particularly useful in the treatment of conditions responsive to CB1 modulation in humans, domesticated companion animals and livestock animals, including appetite disorders, obesity and addictive disorders. Pharmaceutical compositions and methods for using them to treat such disorders are provided, as are methods for using such ligands for receptor localization studies and various in vitro assays.
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Page/Page column 63
(2008/06/13)
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- A photoactivated precipiton for reagent sequestration in solution-phase synthesis
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Precipitons are molecular phase tags for chemical separations. They can be switched from a high-solubility to a low-solubility state to facilitate product, reagent, or catalyst isolation. This paper presents the first photoactivated precipiton and demonstrates that this precipiton is an efficient amine scavenging agent in solution-phase syntheses of amides, ureas, and imines. This approach to amine scavenging offers advantages over solid-phase scavenging methods. The amine is captured in a homogeneous medium, so the capture is much faster than seen with isocyanate resins, and only a small excess of the scavenger is required. Copyright
- Bosanac, Todd,Wilcox, Craig S.
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p. 4194 - 4195
(2007/10/03)
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- Antitumor Imidazotetrazines. 1. Synthesis and Chemistry of 8-Carbamoyl-3-(2-chloroethyl)imidazo-1,2,3,5-tetrazin-4(3H)-one, a Novel Broad-Spectrum Antitumor Agent
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Interaction of 5-diazoimidazole-4-carboxamide and alkyl and aryl isocyanates in the dark affords 8-carbamoyl-3-substituted-imidazo-1,2,3,5-tetrazin-4(3H)-ones.In cold methanol or ethanol, the 3-(2-chloroethyl) derivative 7a decomposes to afford 2-azahypoxanthine (14) and methyl and ethyl N-(2-chloroethyl)carbamates, respectively.Compound 7a has curative activity against L-1210 and P388 leukemia and may act as a prodrug modification of the acyclic triazene 5-imidazole-4-carboxamide (MCTIC), since it ring opens to form the triazene in aqueous sodium carbonate.
- Stevens, Malcolm F. G.,Hickman, John A.,Stone, Robert,Gibson, Neil W.,Baig, Ghouse Unissa,et al.
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p. 196 - 201
(2007/10/02)
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