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N2 - An efficient synthesis of hyperbranched poly(m-phenylene)s is achieved by Suzuki polycondensation of a m-terphenyl-derived branched AB2 monomer. The resulting hyperbranched polymers show high molecular weight and relatively low polydispersity and are readily soluble in common organic solvents. A catalyst system composed of Pd(OAc)2 and S-Phos was found to be highly active in the present Suzuki polycondensation protocol. The molecular weight and polydispersity of the polymer are controllable by varying the catalyst loading and the starting monomer concentration. Experimental results are consistent with a pseudo-chain-growth pathway that involves intramolecular catalyst transfer during polymerization. Furthermore, the triflate end groups of the hyperbranched poly(m-phenylene)s can be efficiently converted to other functionalities via in situ Suzuki-Miyaura cross-couplings.
Thieme E-Books & E-Journals - Synthesis / Issue
More recently, the unnatural biflavones 43 and 44 were prepared by the Suzuki-Miyaura reaction of appropriately functionalized flavones using Pd(PPh3)4 as a catalyst . The biflavones 43 and 44 together with other unnatural biflavones synthesized by the Stille coupling reaction were tested for inhibition of group II secretory phospholipase A2 (SPLA2IIA) and their inhibitory activity compared with that of the natural biflavones amentoflavone (26) and ochnaflavone. Of the active compounds, 44 () was also found to exhibit inhibitory potency comparable to that of amentoflavone (26) whereas 43 () exhibited a weaker activity .
As a result of the readily availability of 3-halochromones and their potential to be elaborated into a wide range of compounds by coupling with different boronic acids in the final stages of the synthesis, several groups have taken advantage of the Suzuki coupling reaction for the synthesis of libraries of novel compounds based on the isoflavone scaffold for biological activity studies [,,]. For example, Vasselin synthesized a series of fluoro, methoxy, nitro and amino isoflavones (50a–o) from appropriately substituted 3-iodochromones and arylboronic acids () . However, an attempt to prepare 5,7-dibenzyloxy-3-iodochromone from 4,6-dibenzyloxy-2-hydroxyacetophenone resulted in an inseparable mixture of products while a poor yield (29%) was obtained for 3-iodo-5,7-dimethoxychromone from the corresponding enaminoketone.
18/12/2016 · Akira Suzuki, NP 2010 in Chemistry, ..
The key steps in the synthesis of robustaflavone (39) were TlOAc-mediated C-6 iodination of apigenin derivate 36 to give the 6-iodoflavone 37 and synthesis of the 3'-flavonylboronate (35) by palladium-catalyzed cross-coupling of 3'-iodoflavone 30a with bis(pinacolato)diboron () . An attempt to convert the 3'-iodoflavone 30a into the corresponding boronic acid by the procedure employed in the synthesis of amentoflavone (26) was unsuccessful. The two precursors were coupled under standard Suzuki conditions to give 38, which was demethylated with BBr3 to give the target compound robustaflavone (39).
Synthesis Organic Compound CHEM Study - Duration: 21:26
Poly(carbazole-3,6-diyl--9,9-dihexylfluorene-2,7-diyl)s bearing the functional groups such as imine, 1,3-oxazoline and pyridine at the 1,8-positions of the carbazole unit were synthesized by the Suzuki coupling polymerization to examine the structure–properties relationship. The formation of an intramolecular hydrogen bonding between the carbazole NH proton and the functional group influenced the UV–Vis and PL spectra, and generally decreased the fluorescence quantum yield. The chelate coordination of metal ions also had an impact on the optical properties.
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Zuo obtained a number of aryl-substituted chalcones by preparing either the aryl-substituted acetophenone or benzaldehyde via the Suzuki-Miyaura reaction, followed by the traditional Claisen-Schmidt synthesis of the chalcones. Most of the synthesized compounds had moderate to strong anticancer activity against five cancer cell lines, and have NF-kB nuclear translocation inhibition activities . Vieira used a similar approach by using the Claisien-Schmidt reaction to prepare brominated chalcones which were subjected to the Suzuki-Miyaura reaction to yield arylated chalcones . In this investigation, the emphasis was on developing reaction conditions that are environmentally benign and they introduced the use of the non-toxic polyethyleneglycol as solvent for the reaction.
Spring-GreenChem - Suzuki Reactions
Poly(-caprolactone)2--poly(L-lactide)2 miktoarm block copolymers were successfully synthesized via ring-opening polymerization with protection–deprotection procedure, using pentaerythritol as initiator. The degradation behavior of (PCL)2--(PLLA)2 microspheres, which were produced by oil-in-water emulsion solvent extractionevaporation method, showed that the degradation occurred from the surface to the interior as a combined degradation model with surface erosion and bulk degradation.