14437-03-7Relevant articles and documents
Atom-economy synthesis of N-substituted carbamate from urea derivative and dimethyl carbonate catalyzed by La/SiO2: Characterization and activity
Guo, Xiaoguanga,Shang, Jianpenga,Li, Jiana,Wang, Liguoa,Ma, Yuboa,Shi, Feng,Deng, Youquan
, p. 164 - 170 (2010)
A series of silica gel immobilized lanthanum catalysts were prepared for the atom-economy synthesis of N-substituted carbamates from urea derivatives and dimethyl carbonate. The La/SiO2 catalysts with lanthanum loadings varied from 1.3 wt% to 8.5 wt% were characterized by AES, BET, XRD, TEM, FT-IR, XPS and TPD. According to the characterization, lanthanum species with particle sizes of 5-10 nm on the surface of silica gel were formed. The catalysts were all amorphous and the surface areas were 336.5-530.2 m2/g. NH3-TPD analysis showed that all samples exhibited similar acid strength with different acid amounts. FT-IR measurement indicated that the component of lanthanum species on the catalyst surface were La(OH)3, LaOOH and hydrated La2O3. Also, the peak value of the absolute amount of LaOOH was obtained with 4.3 wt% lanthanum loading. The BET surface area decreased dramatically when the lanthanum loading was above 4.3 wt%. In consideration of the results obtained from the catalytic reactions, it could be concluded that LaOOH was the possible active species and high surface area was important for the high catalytic activity.
Alkene Syn- And Anti-Oxyamination with Malonoyl Peroxides
Curle, Jonathan M.,Perieteanu, Marina C.,Humphreys, Philip G.,Kennedy, Alan R.,Tomkinson, Nicholas C. O.
supporting information, p. 1659 - 1664 (2020/02/13)
Malonoyl peroxide 6 is an effective reagent for the syn- or anti-oxyamination of alkenes. Reaction of 6 and an alkene in the presence of O-tert-butyl-N-tosylcarbamate (R3 = CO2 tBu) leads to the anti-oxyaminated product in up to 99% yield. Use of O-methyl-N-tosyl carbamate (R3 = CO2Me) as the nitrogen nucleophile followed by treatment of the product with trifluoroacetic acid leads to the syn-oxyaminated product in up to 77% yield. Mechanisms consistent with the observed selectivities are proposed.
Sulfonyl Azides as Precursors in Ligand-Free Palladium-Catalyzed Synthesis of Sulfonyl Carbamates and Sulfonyl Ureas and Synthesis of Sulfonamides
Chow, Shiao Y.,Stevens, Marc Y.,Odell, Luke R.
, p. 2681 - 2691 (2016/04/26)
(Chemical Equation Presented). An efficient synthesis of sulfonyl carbamates and sulfonyl ureas from sulfonyl azides employing a palladium-catalyzed carbonylation protocol has been developed. Using a two-chamber system, sulfonyl azides, PdCl2, and CO gas, released ex situ from Mo(CO)6, were assembled to generate sulfonyl isocyanates in situ, and alcohols and aryl amines were exploited as nucleophiles to afford a broad range of sulfonyl carbamates and sulfonyl ureas. A protocol for the direct formation of substituted sulfonamides from sulfonyl azides and amines via nucleophilic substitution was also developed.
Rapid and straightforward transesterification of sulfonyl carbamates
Isaksson, Rebecka,Kumpi?a, Ilze,Larhed, Mats,Wannberg, Johan
supporting information, p. 1476 - 1478 (2016/03/12)
A fast and convenient method for the alkoxy exchange of sulfonyl carbamates by simply heating in a chosen alkyl alcohol is described. No catalysts or additives are required. Microwave heating at 100-120 °C for 20-60 min resulted in good to excellent yields (53-93%) of alkyl (arylsulfonyl)carbamates where the alkyl part originates from the alcohol solvent. The developed protocol was applied to the synthesis of an angiotensin II type 2 receptor (AT2R) ligand.