Copper-catalyzed cross-dehydrogenative coupling of N-arylacrylamides with chloroform using tert-butyl peroxybenzoate as oxidant for the synthesis of trichloromethylated 2-oxindoles
“…In this process, an initiator is needed to promote radical polymerization. Previous studies have been conducted using tert -butyl peroxybenzoate (TBPB) as an initiator to accelerate the polymerization by producing radical chains ( Chan et al., 2015 ; Zhou et al., 2017 ). Figure 1 Scheme of reaction polyethylene-graft-maleic anhydride-graft-chitosan blend.…”
Plastics based on low-density polyethylene (LDPE) blends generally have limited miscibility, and it is difficult to obtain a homogeneous blend. Although they show excellent properties, their thermal degradation rate is a concern. This work aims to realize a homogeneous blend with higher chitosan concentration, thus expected to increase its degradation properties. An extrusion technique successfully synthesized LDPE and chitosan blends. The mixtures were prepared by adding maleic anhydride (MA) and tert-butyl peroxybenzoate (TBPB) as a compatibilizer and initiator, respectively. The addition of MA and TBPB resulted in homogeneous blends and using chitosan concentration of 40 %wt resulted in better tensile strength and elongation at break. The water uptake increased along with chitosan concentration in the blends. The thermal behavior analysis of the blends conducted by simultaneous TG/DTA revealed that the increase of chitosan concentration tends to improve the blend's thermal degradation slightly. Moreover, chitosan addition resulted in approximately a hundred times larger biodegradability compared to plastics based on LDPE alone.
“…In this process, an initiator is needed to promote radical polymerization. Previous studies have been conducted using tert -butyl peroxybenzoate (TBPB) as an initiator to accelerate the polymerization by producing radical chains ( Chan et al., 2015 ; Zhou et al., 2017 ). Figure 1 Scheme of reaction polyethylene-graft-maleic anhydride-graft-chitosan blend.…”
Plastics based on low-density polyethylene (LDPE) blends generally have limited miscibility, and it is difficult to obtain a homogeneous blend. Although they show excellent properties, their thermal degradation rate is a concern. This work aims to realize a homogeneous blend with higher chitosan concentration, thus expected to increase its degradation properties. An extrusion technique successfully synthesized LDPE and chitosan blends. The mixtures were prepared by adding maleic anhydride (MA) and tert-butyl peroxybenzoate (TBPB) as a compatibilizer and initiator, respectively. The addition of MA and TBPB resulted in homogeneous blends and using chitosan concentration of 40 %wt resulted in better tensile strength and elongation at break. The water uptake increased along with chitosan concentration in the blends. The thermal behavior analysis of the blends conducted by simultaneous TG/DTA revealed that the increase of chitosan concentration tends to improve the blend's thermal degradation slightly. Moreover, chitosan addition resulted in approximately a hundred times larger biodegradability compared to plastics based on LDPE alone.
“…In interposition substitution, a compound with a methyl group is cyclized only in its ortho position ( 3t ), which is consistent with the result that products derived from cyclization at the more hindered site were preferred in most cases. 11…”
A novel and unprecedented method for the polychlorinated alkylation annulation of N-arylacrylamide has been developed under electrochemical condition with diazo salt as the mediator at the cathode reduction and CH2Cl2...
“…a Reactions were performed on a 0.3 mmol scale in CHCl 3 (0.3 M) containing Cu(OAc) 2 (0.2 equiv), TBPB (2.5 equiv), and MeOH (2.5 equiv) at 120 °C for 12 h. On the basis of the above-described control experiments, we propose the mechanism outlined in Scheme 6. In the presence of copper, initially homolytic cleavage of TBPB accelerated by Ln-Cu(II) forms an Ln-Cu(III)-OBz complex and tert-butoxyl radical, 24 In conclusion, we have developed a novel approach for the direct alkoxycarbonylation of furans as well as other heteroarenes via one-step copper-mediated reaction of three components, i.e., heteroarene, alcohol, and CHCl 3 . This method was found as the first use of a radical pathway to construct FDCA derivatives based on a C 5 platform.…”
Section: Scheme 4 Alkoxycarbonylation Reactions Of Various Heteroaren...mentioning
confidence: 97%
“…On the basis of the above-described control experiments, we propose the mechanism outlined in Scheme . In the presence of copper, initially homolytic cleavage of TBPB accelerated by Ln-Cu(II) forms an Ln-Cu(III)-OBz complex and tert -butoxyl radical, which abstracts the hydrogen atom of CHCl 3 to generate ·CCl 3 radical. Addition of ·CCl 3 radical to methyl 2-furoate generates intermediate A , after which single electron transfer (SET) of the Ln-Cu(III)-OBz species takes place to produce the corresponding carbocation intermediate B and regenerate the Ln-Cu(II) species.…”
We report an efficient approach for
direct alkoxycarbonylation
of furans as well as other heteroarenes via a one-step copper-mediated
reaction of three components (i.e., heteroarene, alcohol, and CHCl3). The copper additive was confirmed to simultaneously promote
the reaction in three pathways: oxidant cracking, single electron
transfer, and alcoholysis. By means of this protocol, various functionalized
furancarboxylates and other heteroarenecarboxylates were facilely
obtained in moderate to good yields.
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