6744-64-5Relevant articles and documents
Bulky Barbiturates as Non-Toxic Ionic Dye Insulators for Enhanced Emission in Polymeric Nanoparticles
Andreiuk, Bohdan,Aparin, Ilya O.,Klymchenko, Andrey S.,Reisch, Andreas
, p. 12877 - 12883 (2021)
Bulky hydrophobic counterions (weakly coordinating anions) can insulate ionic dyes against aggregation-caused quenching (ACQ) and enable preparation of highly fluorescent dye-loaded nanoparticles (NPs) for bioimaging, biosensing and light harvesting. Here, we introduce a family of hydrophobic anions based on fluorinated C-acyl barbiturates with delocalized negative charge and bulky non-polar groups. Similarly to fluorinated tetraphenylborates, these barbiturates prevent ACQ of cationic dye alkyl rhodamine B inside polymer NPs made of biodegradable poly(lactic-co-glycolic acid) (PLGA). Their efficiency to prevent ACQ increases for analogues with higher acidity and bulkiness. Their structure controls dye-dye communication, yielding bright NPs with on/off switching or stable emission. They enhance dye encapsulation inside NPs, allowing intracellular imaging without dye leakage. Compared to fluorinated tetraphenylborates known as cytotoxic transmembrane ion transporters, the barbiturates display a significantly lower cytotoxicity. These chemically available and versatile barbiturate derivatives are promising counterion scaffolds for preparation of bright non-toxic fluorescent nanomaterials.
Co-N-doped carbon nanotubes supported on diatomite for highly efficient catalysis oxidative carbonylation of amines with CO and air
Li, Jiangwei,Tu, Dong-huai,Li, Yani,Wang, Weiqiang,Yu, Qinwei,Yang, Jianming,Lu, Jian
, p. 112 - 116 (2017/10/09)
Cobalt-nitrogen-doped carbon nanotubes stably supported on diatomite were obtained by employing Co(OAc)2/phenanthroline. The resulting material was found to be excellent catalysts for the carbonylation of a variety of amines with CO other than phosgene. Both high activity and selectivity were achieved in this carbonylation process, and it allows air as a cheap oxidizing agent. Moreover the catalyst could be recycled for several times with relatively higher activity compared to homogeneous catalyst palladium acetate.
Ruthenium-Catalyzed Urea Synthesis by N-H Activation of Amines
Krishnakumar, Varadhan,Chatterjee, Basujit,Gunanathan, Chidambaram
supporting information, p. 7278 - 7284 (2017/06/23)
Activation of the N-H bond of amines by a ruthenium pincer complex operating via amine-amide metal-ligand cooperation is demonstrated. Catalytic formyl C-H activation of N,N-dimethylformamide (DMF) is observed in situ, which resulted in the formation of CO and dimethylamine. The scope of this new mode of bond activation is extended to the synthesis of urea derivatives from amines using DMF as a carbon monoxide (CO) surrogate. This catalytic protocol allows the synthesis of simple and functionalized urea derivatives with liberation of hydrogen, devoid of any stoichiometric activating reagents, and avoids the direct use of fatal CO. The catalytic carbonylation occurred at low temperature to provide the formamide; a formamide intermediate was isolated. The consecutive addition of different amines provided unsymmetrical urea compounds. The reactions are proposed to proceed via N-H activation of amines followed by CO insertion from DMF and with liberation of dihydrogen.
Direct extraction of carbonyl from waste polycarbonate with amines under environmentally friendly conditions: Scope of waste polycarbonate as a carbonylating agent in organic synthesis
Singh, Sukhdeep,Lei, Yong,Schober, Andreas
, p. 3454 - 3460 (2015/02/19)
An efficient green method for converting waste polycarbonate into urea derivatives by reacting with primary amines has been developed. Simple treatment of polycarbonate plastic with primary amines in a closed vial at 80 °C without using any catalyst and toxic solvents made this process environmentally friendly. Digestion of the waste polycarbonate obtained from CDs and DVDs with amines affords functionalized urea and 4,4′-(propane-2,2-diyl)diphenol (BPA, bisphenol-A). The procedure is optimized to get maximum conversion of polymer to urea and its derivatives as a major product. The purification procedure to isolate the urea derivatives in the presence of bisphenol-A has been tuned to avoid chromatographic procedures. This environmentally friendly method provides (i) an alternative for recycling BPA from polycarbonate, (ii) a method of obtaining useful product like urea derivatives, (iii) scope for new carbonylating agents in organic synthesis, (iv) an amine functionalized polycarbonate surface. This journal is
Direct synthesis of acyl azides from carboxylic acids using 2-azido-l,3-dimethylimidazolinium chloride
Kitamura, Mitsuru,Tashiro, Norifumi,Takamoto, Yusuke,Okauchi, Tatsuo
scheme or table, p. 731 - 733 (2011/01/08)
Acyl azides were directly synthesized from carboxylic acids by the treatment with 2-azido-l,3-dimethylimidazolinium chloride (ADMC, 1) and amine. This procedure resulted in acyl azides in good yields and was applied to the amidation of amino acid derivatives without racemization of the products.
A study on the stability of 5,5-diamino-substituted- 1,4,2- oxathiazoline derivatives
Jung, Keum Shin,Lee, Hong Jung,Song, Hyun Nam,Kim, Jae Nyoung
, p. 1879 - 1884 (2007/10/03)
5,5-Diamino-substituted-1,4,2-oxathiazoline derivatives 3 as potential prodrugs, which were easily prepared from hydroximoyl chlorides I and the appropriate thiourea derivatives 2, were decomposed instantaneously into isothiocyanates 4 and the corresponding urea derivatives 5 irrespective of the substituents.
Ureas in Organic Synthesis. XI. Reactions of Arylcarbinols with Carbamides in Synthesis of Biologically Active Arylmethylureas
Bakibaev, A. A.
, p. 1433 - 1437 (2007/10/03)
The reaction of arylcarbinols with carbamide in the presence of acids affords the corresponding arylmethylureas.
N, N′ - Ditritylurea and analogs as hosts in crystalline clathrate complexes: Synthesis and selectivity studies
Ng, Kwok-Keung Daniel,Hart, Harold
, p. 7883 - 7906 (2007/10/02)
Of 38 hosts, most of them new, designed on the 'wheel-and-axle' model, 24 formed clathrate complexes with small molecules; 95 new host/guest combinations are described (Table 6). Selectivity studies (Table 7) show, in some instances, substantial discrimin
