1862-07-3Relevant articles and documents
Regioselectivity control in Diels-Alder reactions of surfactant 1,3- dienes with surfactant dienophiles
Jaeger, David A.,Su, Dan,Zafar, Abdullah,Piknova, Barbora,Hall, Stephen B.
, p. 2749 - 2757 (2000)
The ability of surfactant aggregate-H2O interfaces to control the regioselectivity of Diels-Alder reactions has been investigated. Cycloadditions of surfactant 1,3-dienes 2-[[3-(dimethyldodecylsilyl)-1,3- butadien-2-yl]thio]-N,N,N-trimethyl-1-ethanaminium iodide (1a) and 6-[[3- (dimethyloctylsilyl)-1,3-butadien-2-yl]thio]-N,N,N-trimethyl-1-hexanaminium iodide (1b) with surfactant dienophiles (E)-2-[[[2- (dodecoxycarbonyl)ethenyl]carbonyl]oxy]-N,N,N-trimethyl-1-ethanaminium iodide (2a) and (E)-6-[[[2-(octoxycarbonyl)ethenyl]carbonyl]oxy]-N,N,N-trimethyl-1- hexanaminium bromide (2b) within their aqueous mixed micelles have been performed at 25(35) °C. The cycloaddition of 1a and 2a gave a 30:1 ratio of trans-1-[(2-trimethylammonio)ethylthio]-2-(dimethyldodecylsilyl)-4- (dodecoxycarbonyl)-5-[(2-trimethylammonio)ethoxycarbonyl]-1-cyclohexene dihalide (15a) and trans-1-[(2-trimethylammonio)ethylthio]-2- (dimethyldodecylsilyl)-4-[(2-trimethylammonio)ethoxycarbonyl]-5- (dodecoxycarbonyl)-1-cyclohexene dihalide (16a), respectively, and that of 1b and 2b a 6.6:1 ratio of trans-1-[(6-trimethylammonio)hexylthio]-2- (dimethyloctylsilyl)-4-(octoxycarbonyl)-5-[6- (trimethylammonio)hexoxycarbonyl]-1-cyclohexene dihalide (15b) and trans-1- [(6-trimethylammonio)hexylthio]-2-(dimethyloctylsilyl)-4-[6- (trimethylammonio)hexoxycarbonyl]-5-(octoxycarbonyl)-1-cyclohexene dihalide (16b), respectively. The excess of 15 over 16 is consistent with the reaction of 1 and 2 within mixed aggregates in their preferred orientations at the aggregate-H2O interface. The greater regioselectivity obtained in the reaction of 1a and 2a is ascribed to the shorter tether between their reactive functional groups and quaternary ammonium headgroups. A monolayer study of 15a and 16a was also performed.
Catalytic Hydrogenation of Thioesters, Thiocarbamates, and Thioamides
Luo, Jie,Rauch, Michael,Avram, Liat,Ben-David, Yehoshoa,Milstein, David
supporting information, p. 21628 - 21633 (2021/01/11)
Direct hydrogenation of thioesters with H2 provides a facile and waste-free method to access alcohols and thiols. However, no report of this reaction is documented, possibly because of the incompatibility of the generated thiol with typical hydrogenation catalysts. Here, we report an efficient and selective hydrogenation of thioesters. The reaction is catalyzed by an acridine-based ruthenium complex without additives. Various thioesters were fully hydrogenated to the corresponding alcohols and thiols with excellent tolerance for amide, ester, and carboxylic acid groups. Thiocarbamates and thioamides also undergo hydrogenation under similar conditions, substantially extending the application of hydrogenation of organosulfur compounds.
Efficient ruthenium-catalyzed N-methylation of amines using methanol
Dang, Tuan Thanh,Ramalingam, Balamurugan,Seayad, Abdul Majeed
, p. 4082 - 4088 (2015/11/11)
An in situ-generated complex from [RuCpCl2]2 and dpePhos ligand is reported as an efficient catalyst in the presence of 5 mol % of LiOtBu for the N-methylation of amines using methanol as the methylating agent at moderate conditions, following hydrogen borrowing strategy. This simple catalyst system provides selective N-monomethylation of substituted primary anilines and sulfonamides as well as N,N dimethylation of primary aliphatic amines in excellent yields at 40-100 °C with good tolerance to reducible functional groups. The catalytic intermediate CpRu(dpePhos)H was isolated and was shown to be active for methylation in the absence of base.
Synthesis and biological activity of dialkylphosphocholines
Lukac, Milos,Mrva, Martin,Fischer-Fodor, Eva,Lacko, Ivan,Bukovsky, Marian,Miklasova, Natalia,Ondriska, Frantisek,Devinsky, Ferdinand
scheme or table, p. 6346 - 6349 (2010/06/11)
A series of dialkylphosphocholines were prepared and evaluated for their biological activity. The antiprotozoal activity was determined against Acanthamoeba lugdunensis. Compound 15 exhibited excellent trophocidal activity. None of the tested dialkylphosphocholines exhibited better fungicidal activity against Candida albicans than miltefosine. The antineoplastic activity was determined against HeLa. The most cytotoxic was compound 10, which was more active against tumor cells as against normal cells.
