• Title/Summary/Keyword: Ureas

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A Facile Synthesis of N,N'-Disubstituted Ureas from Amide and Amine by Using N-Bromophthalimide (NBP) and Silvercetate in One Pot

  • Park, Min-Soo;Choi, Chang-Uk
    • Archives of Pharmacal Research
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    • v.17 no.1
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    • pp.39-41
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    • 1994

  • Various N,N'-disubstituted ureas 5 were easily prepared from the corresponding primary amide 1 by tratment with N-Bromophthalimide $(NBP)-AgOAc-RNH$_{2}$ 4 in dry N,N-dimrthylformamide (DMF). This reaction envolved the intemediate formation of isocyanate 3 from amide 1 via Hofmann rearrangement by treatment with AgOAc and NBP and nucleophilic addition of amine 4 to this isocyante 3. This method is simple enough to be applied to the synthesis of various N,N'-disubstututed ureas scale conviently.

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Effect of Ureas on the Hydrophobic Properties of Aqueous Poly(ethylene oxide) Solutions by Viscometry

  • Sang Il Jeon;Hak-Kyu ChoI;Seung Chang Ra;Byoung Jip Yoon
    • Bulletin of the Korean Chemical Society
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    • v.15 no.9
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    • pp.748-751
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    • 1994

  • Poly(ethylene oxide) (PEO) in aqueous solutions has a hydrophobic character which can induce the hydrophobic interaction between its nonpolar parts. The hydrophobic properties of aqueous PEO solutions are studied by the viscometry in terms of the water structure-making and -breaking capabilities of added solutes of ureas. The results show that the contracted conformation of PEO of low molecular weight, namely poly(ethylene glycol) (PEG), does not result from the hydrophobic interaction between the nonpolar parts of PEO but it can participate in a hydrophobic interaction between the nonpolar parts of PEO and added ureas solutes with nonpolar groups, which can induce a large hydrodynamic volume and increase the viscosity. On the other hand, the PEO of large molecular weight seems to behave like any other water soluble polymers with nonpolar parts and its conformation in aqueous solutions is well explained in terms of water structure perturbing capabilities of added ureas.

  • https://doi.org/10.5012/bkcs.1994.15.9.748 인용 PDF

The Effect of Organic Solvent in the Dyeing of Silk Fiber (II) -The Change of Dyeability by Addition of Ureas- (견섬유의 염색에 있어서 첨가용제의 영향(II) -요소류 첨가에 따른 염색성의 변화-)

  • Yoon, Nam-Sik;Lim, Yong-Jin;Lee, Dong-Soo;Rhee, In-Jeon
    • Textile Coloration and Finishing
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    • v.2 no.3
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    • pp.36-42
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    • 1990

  • The effect of urea and its derivatives, which are known as structure breakers of water, in the dyeing of silk with acid dyes was investigated. Without ureas the maximum dye uptake was observed at $60^{\circ}C$ when dyed with Milling Cyanine 5R, but in the presence of ureas the maximum dye uptake was decreased and its temperature also shifted to lower regin in the order of urea >N-methyl urea > N,N-dimethyl urea>tetramethyl urea. These tendencies were more marked in the dyeing of silk fiber with Orange II, a typical levelling type acid dye. These can be interpreted as the decrease in the hydropholic interaction between fiber molecules which results in the broadening of the inter micelie spacing. The increased partition coefficient of dye molecules in the bath by the action of ureas also contributes to dyeing results, and it can be seen from the spectral characteristics of dyes in aqueous urea solution.

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Synthesis and Cytotoxicity of New 3-Alkyl-1-(1-methyl-2-phenylethyl)ureas Related to Ceramide

  • Lim, Sejin;Ryu, Jae-Hark;Im, Chaeuk;Yim, Chul-Bu
    • Archives of Pharmacal Research
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    • v.26 no.4
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    • pp.270-274
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    • 2003

  • A series of new 3-alkyl-1-(1-methyl-2-phenylethyl)ureas related to ceramide was synthesized and evaluated for their in vitro cytotoxic activity against five human tumor cell lines. The urea analogue (2b) of 813 showed comparable or slightly more potent cytotoxic activity as compared to B13, indicating that urea does appear to serve as a bioisostere of amide.

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