A facile synthesis of unsymmetrical ureas

Bogolubsky, Andrey V.; Ryabukhin, Sergey V.; Pipko, Sergey E.; Lukin, Oleg; Shivanyuk, Alexander; Mykytenko, Dmytro; Tolmachev, Andrey A.

doi:10.1016/j.tet.2011.03.101

Cited by 23 publications

(22 citation statements)

References 20 publications

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“…), the existence of 4 (10 % yield), 6 (32 % yield), and remaining 1 (38 %) was confirmed by 19 F NMR spectroscopic analysis of the mixture (Scheme ). Because there are sufficient temperature differences between the boiling points of each carbonate ( 4 : 97 °C, 1 : 118 °C), it is theoretically possible to isolate 4 . Actually, distillation of the resulting mixture afforded fractions with different composition ratios.…”

Section: Resultsmentioning

confidence: 99%

“…), the existence of 4 (10 %y ield), 6 (32 % yield), and remaining 1 (38 %) wasc onfirmed by 19 FNMR spectroscopic analysis of the mixture (Scheme 7). Because there are sufficient temperature differences between the boilingp oints of each carbonate (4:9 7 8C, [36] 1:1 18 8C [37] ), it is theoretically possible to isolate 4.A ctually,d istillationo ft he resulting mixture afforded fractionsw ith different composition ratios. Althoughi tw as difficult to isolate 4 from the crude mixture by simple distillation on al aboratory scale, it is assumed that 4 could be isolatedb ym ultistage distillation (see the Supporting Information for details, such as timecourse plot, fractional distillation, and control experiments).…”

Section: Methods IVmentioning

confidence: 99%

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Synthesis of Fluorinated Dialkyl Carbonates from Carbon Dioxide as a Carbonyl Source

et al. 2020

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Fluorinated dialkyl carbonates (DACs), which serve as environmentally benign phosgene substitutes, were produced successfully from carbon dioxide either directly or indirectly. Nucleophilic addition of 2,2,2‐trifluoroethanol to carbon dioxide and subsequent reaction with 2,2,2‐trifluoroethyltriflate (3 a) afforded bis(2,2,2‐trifluoroethyl) carbonate (1) in up to 79 % yield. Additionally, carbonate 1 was obtained through the stoichiometric reaction of 3 a and cesium carbonate. Although bis(1,1,1,3,3,3‐hexafluoro‐2‐propyl) carbonate (4) was difficult to obtain by either of the above two methods, it could be synthesized through the transesterification of carbonate 1.

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Section: Resultsmentioning

confidence: 99%

Section: Methods IVmentioning

confidence: 99%

Synthesis of Fluorinated Dialkyl Carbonates from Carbon Dioxide as a Carbonyl Source

et al. 2020

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“…Bis(2,2,2-triuoroethyl)carbonate and 2,2,2-triuoroethyl chloroformate were prepared as previously described. 31 IR spectra were recorded on Perkin-Elmer Spectrum BX II. NMR spectra were acquired on Bruker Avance DRX 500 spectrometer using CDCl 3 or DMSO-d 6 as a solvent and tetramethylsilane (TMS) as an internal standard.…”

Section: Methodsmentioning

confidence: 99%

Facile one-pot synthesis of 4-substituted semicarbazides

et al. 2015

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A diverse library of twenty-five 4-mono-and disubstituted semicarbazides was prepared in a one-pot twostep approach. The method includes formation of a carbamate from bis(2,2,2-trifluoroethyl)carbonate or 2,2,2-trifluoroethylchloroformate and a primary or secondary amine and subsequent interaction of the carbamate with hydrazine to result in a semicarbazide. The approach allowed to obtain 4-substituted semicarbazides on a large scale in good yield and high purity.

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“…[57] This reagent is prepared from bis(trichloromethyl) carbonate and 2,2,2-trifluoroethanol. It readily reacts with both aliphatic and aromatic primary amines at ambient temperature in triethylamine/acetonitrile to give the corresponding 2,2,2-trifluoroethyl carbamates in nearly quantitative yields.…”

Section: Acyclic Unfunctionalized Ureasmentioning

confidence: 99%