7474-86-4Relevant articles and documents
Hydration effects on the triplet exciplex between 2,3-dihalo-1,4- naphthoquinone and furan studied by steady-state and laser flash photolyses
Yamaji, Minoru,Kurumi, Masanori,Kimura, Hiroko,Shizuka, Haruo
, p. 1859 - 1865 (1999)
Photochemical interactions of triplet 2,3-dibromo- and 2,3-dichloro- 1,4-naphthoquinones (DBNQ and DCNQ) with furan in acetonitrile (ACN) and a mixture of ACN and water (4:1 v/v) were investigated by means of product analysis, steady-state and nanosecond laser flash photolysis. The photoproducts of DBNQ and DCNQ in the presence of furan in ACN were 2-bromo- and 2-chloro-3-(2-furyl)-1,4-naphthoquinones with the quantum yields for production (Φ(pro) of 0.12 and 0.05, respectively, whereas in aqueous ACN, 2,3-dibromo- and 2,3-dichloro-1,4-dihydroxynaphthalenes Φ(pro) = 0.12 and 0.17, respectively. By nanosecond laser photolysis at 355 nm, it was found that triplet DBNQ and DCNQ were quenched by furan with rate constants (k(q)) of 2.0 x 109 and 3.0 x 109 dm3 mol-1 s-1 in ACN and 6.1 x 109 and 6.4 x 109 dm3 mol s-1 in aqueous ACN, respectively. After depletion of triplet DBNQ and DCNQ, no transient absorption in the region 360-600 nm was observed in ACN while the corresponding anion radicals having molar absorption coefficients (ε(ani)) of 7700 and 7900 dm3 mol-1 cm-1 at 400 nm, respectively, were formed in aqueous ACN. The initial interaction of triplet DBNQ and DCNQ with furan in aqueous ACN was found to be electron transfer with efficiencies (α(et)) of 0.22 and 0.23, respectively, while that in ACN was presumed to be dominated by induced quenching. The deactivation mechanism of triplet DBNQ and DCNQ by furan was discussed from the viewpoint of the free energy changes (ΔG) for electron transfer. It was suggested that the triplet exciplex with weak charge-transfer character played an important role being controlled by the solvation energy in the ΔG term.
Direct Synthesis of Hydroquinones from Quinones through Sequential and Continuous-Flow Hydrogenation-Derivatization Using Heterogeneous Au–Pt Nanoparticles as Catalysts
Miyamura, Hiroyuki,Tobita, Fumiya,Suzuki, Aya,Kobayashi, Shū
supporting information, p. 9220 - 9224 (2019/06/13)
Pt–Au bimetallic nanoparticle catalysts immobilized on dimethyl polysilane (Pt–Au/(DMPSi-Al2O3)) have been developed for selective hydrogenation of quinones to hydroquinones. High reactivity, selectivity, and robustness of the catalysts were confirmed under continuous-flow conditions. Various direct derivatizations of quinones, such as methylation, acetylation, trifluoromethanesulfonylation, methacrylation, and benzoylation were successfully performed under sequential and continuous-flow conditions to afford the desired products in good to excellent yields. Especially, air-sensitive hydroquinones, such as anthrahydroquinones and naphthohydroquinones, could be successfully generated and derivatized under closed sequential and continuous-flow conditions without decomposition.
Palladium-catalyzed chemo- and regioselective cross-coupling reactions of 2,3-dichloronaphthalene-1,4-bistriflate Dedicated to Prof. Kimoon Kim
Hassan, Zahid,Al-Shidhani, Sulaiman,Al-Ghafri, Ahmed,Al-Harrasi, Ahmed,Hussain, Javid,Csuk, Rene
supporting information, p. 7141 - 7144 (2015/12/12)
Palladium-catalyzed chemoselective and regioselective cross-coupling reactions of 2,3-dichloro-1,4-(trifluoromethanesulfonyloxy)naphthalene with aryl boronic acids selectively afforded a variety of mono-, di-, and tetraphenylnaphthalenes. These reactions
