博文

450-95-3 Linking of Alcohols with Vinyl Azides

https://www.lookchem.com/CASDataBase_450-95-3.htm  A protocol to link alcohols with vinyl azides has been established through fluoro- or bromo-alkoxylation of vinyl azides to provide α-alkoxy-β-haloalkyl azides. A series of primary and secondary alcohols including natural products and their derivatives such as sugars and steroids were successfully anchored with vinyl azides. The as-prepared cyanine dye linked testosterones were capable of rapid cell membrane imaging in real time. 

75-35-4 Laser-induced Decomposition of 1,1,2-Trichloroethane

https://www.lookchem.com/CASDataBase_75-35-4.htm  CH 2 ClCHCl 2  was photolyzed with a focusing geometry using the P(24) line of the 10.6 μm CO 2  band (940.6 cm -1 ).The final products of neat photolysis were cis- and trans-CHCl=CHCl, CH 2 =CCl 2 , CH 2 =CHCl, CH<*>CCl, CH<*>CH, and C 4 H 2 .The relative yield of CH 2 =CCl 2  in particular was strongly dependent on CH 2 ClCHCl 2  pressure and sensitive to the addition of H atom containing molecules.A series of diagnostic experiments shows that the dichloroethene isomers are formed by three different processes, i.e., infrared multiphoton decomposition, collision-induced decomposition, and radical chain reaction.Infrared multiphoton decomposition and collision-induced decomposition give rise to cis- and trans-CHCl=CHCl predominantly, while the radical chain reaction generates the dichloroethane isomers in comparable amounts at high reactant pressures, the most probable initiation step being the C-Cl bond-scission reaction of

4205-23-6

 https://www.lookchem.com/CASDataBase_4205-23-6.htm A highly selective self-condensation of glycolaldehyde to different C 4  molecules has been achieved using Lewis acidic stannosilicate catalysts in water at moderate temperatures (40–100 °C). The medium-sized zeolite pores (10-membered ring framework) in Sn-MFI facilitate the formation of tetrose sugars while hindering consecutive aldol reactions leading to hexose sugars. High yields of tetrose sugars (74 %) with minor amounts of vinyl glycolic acid (VGA), an α-hydroxyacid, are obtained using Sn-MFI with selectivities towards C 4  products reaching 97 %. Tin catalysts having large pores or no pore structure (Sn-Beta, Sn-MCM-41, Sn-SBA-15, tin chloride) led to lower selectivities for C 4  sugars due to formation of hexose sugars. In the case of Sn-Beta, VGA is the main product (30 %), illustrating differences in selectivity of the Sn sites in the different frameworks. Under optimized conditions, GA can undergo further conversion, leadi

74111-21-0

 https://www.lookchem.com/CASDataBase_74111-21-0.htm (Chemical Equation Presented) Linear (n = 2-18) and cyclic oligomers (n = 3-8) of a cyclohexylether-δ-amino acid (COA) were prepared in high yield and stereopurity. CD spectra of the linear oligomers were indicative of secondary structure formation. X-ray crystal structures of cyclic COA oligomers revealed hydrophobic packing and internal 5- and 10-membered-ring hydrogen bonds. Ether and amide oxygens reside preferably in an ap orientation. This conformational locking is apparently broken by a C-2 substituent in an asymmetric cyclotrimer, for which a zeolithe-like tubular structure was found.

100-64-1 On the Oxidation of Hydroxylamines with o -Iodoxybenzoic Acid

https://www.lookchem.com/CASDataBase_100-64-1.htm o -Iodoxybenzoic acid (IBX) is confirmed as a powerful tool for the oxidation of hydroxylamines. The synthetic route is demonstrated as efficient and user friendly, and is exploited on various carbohydrate-derived N,N-disubstituted hydroxylamines (cyclic, acyclic, and functionalized ones), affording the corresponding nitrones in good yields and regioselectivity. N-Monosubstituted hydroxylamines revealed an interesting divergent behavior depending on the reaction conditions. While IBX oxidation in dimethyl sulfoxide at 45 °C furnished oximes as reported, the oxidation in dichloromethane at room temperature afforded efficiently the unusual corresponding nitroso dimers. 

431-47-0 Direct catalytic oxidation

https://www.lookchem.com/CASDataBase_431-47-0.htm Immobilization of rhodium (palladium)-copper-chloride catalytic systems in ionic liquids as high-boiling-point solvents affects the distribution of propane oxidation products: the acetone yield increases and the yield of alcohols decreases. Propane is oxidized to acetone, bypassing the isopropanol formation step. Methane is oxidized under more severe conditions than propane, giving methyl trifluoroacetate as the main product. Mechanisms of action of the catalytic systems based on rhodium and palladium are close to each other and likely include oxo or peroxo complexes as intermediates. 

762-04-9

762-04-9 New synthesis of trimethylsilyl esters of phosphorus(III) acids  Abstract: A novel synthetically important reaction has been developed for the quick, convenient, and high-yield preparation of trimethylsilyl esters of phosphorus(III) acids, synthetically valuable Michaelis–Arbuzov reaction precursors. Commercially and synthetically available initial compounds used are derivatives of propan-2-ol phosphorylated in the second position capable of long-term storage and available silylating reagents: hexamethyldisilazane, bis(trimethylsilyl)acetamide, and diethyl(trimethylsilyl)amine. Also, a stepwise reaction scheme of the starting compounds with silylating reagents has been proposed. Graphic abstract: [Figure not available: see fulltext.]. https://www.lookchem.com/CASDataBase_762-04-9.htm