ABSTRACT
An unprecedented trifunctionalization of CîC bonds in 2-(1-azidovinyl)-1,1'-biphenyls has been successfully achieved using the NCS/AgNO2 system, leading to the preparation of 6-(dichloro(nitro)methyl)phenanthridines in moderate to good yields. In this process, the NCS/AgNO2 system serves as a NO2 radical initiator as well as a chloro group source. The present protocol is a rare example of the selective construction of densely functionalized phenanthridine derivatives in a one-pot manner.
ABSTRACT
To endow wood plate with antimicrobial properties, waterborne polyurethane (WPU) coatings incorporated with nano cellulose crystalline (NCC) and silver nanoparticles (AgNPs) were prepared. AgNPs were obtained by the chemical reactions of silver nitrate solution and sodium borohydride solution. The scribe testing results showed that the adhesion of the NCC-WPU composites was improved with the addition of NCC. The adhesion reached its peak when the amount of NCC added was 1%. Scanning electron microscopy (SEM) observation displayed that the NCC dispersed into the WPU without aggregation. NCC was well able to bind WPU and wood cell walls tightly together. Atomic force microscopy (AFM) and ultraviolet-visible (UV-vis) results revealed that WPU/NCC/AgNPs composites were homogeneous. This compatibility was also confirmed by transmission electron microscopy (TEM) analysis. The antibacterial property was improved too. When the adding amount of NCC was 0.5%, and the proportion of silver elements added was 5%, the antibacterial effect was at its best. As a comparison, the antibacterial effect of hybrid colloid without the addition of NCC was far less than that of including NCC. The WPU/NCC/AgNPs composite could be applied as an antibacterial coating in wood materials.
ABSTRACT
Selectfluor-mediated simultaneous cleavage of C-O and C-C bonds in α,ß-epoxy ketones has been successfully achieved under transition-metal-free conditions. The reaction gives 1,2-diketone compounds in moderate to good yields involving a ring-opening/benzoyl rearrangement/C-C bond cleavage sequence under oxidative conditions.
ABSTRACT
A novel and facile method for the mild construction of fluorinated fluorenones from nonaromatic precursors (1,6-enynes) mediated by a Cu(0)/Selectfluor system has been successfully achieved. Preliminary mechanistic investigations indicate that the reaction may proceed via an unprecedented annulation/C-C single bond cleavage/fluorination sequence.
Subject(s)
Alkynes/chemistry , Copper/chemistry , Diazonium Compounds/chemistry , Fluorenes/chemistry , Hydrocarbons, Fluorinated/chemical synthesis , Organometallic Compounds/chemistry , Hydrocarbons, Fluorinated/chemistry , Molecular StructureABSTRACT
Palladium-catalyzed nitration of 8-methylquinolines with t-BuONO to give 8-(nitromethyl)quinolines in moderate to excellent yields has been developed involving an sp(3) C-H bond activation. The resulting (nitromethyl)quinolines could be selectively reduced to (1,2,3,4-tetrahydroquinolin-8-yl)methanamines by NaBH4 in the presence of a catalytic amount of NiCl2·6H2O.
ABSTRACT
A general and regiospecific transformation of substituted phenols into the related o-nitrophenols has been achieved via a three-step process involving the palladium-catalyzed chelation-assisted ortho-C-H bond nitration as the key step. In the process, 2-pyridinyloxy groups act as removable directing groups for the palladium-catalyzed ortho-nitration of substituted 2-phenoxypridines, and they can be readily removed in the subsequent conversion of the resulting 2-(2-nitrophenoxy)pyridines into 2-nitrophenols.
