1826-19-3Relevant academic research and scientific papers
Programmed synthesis of arylthiazoles through sequential C-H couplings
Tani, Satoshi,Uehara, Takahiro N.,Yamaguchi, Junichiro,Itami, Kenichiro
, p. 123 - 135 (2014/01/06)
A programmed synthesis of privileged arylthiazoles via sequential C-H couplings catalyzed by palladium or nickel catalysts has been accomplished. This versatile protocol can supply all possible arylthiazole substitution patterns (2-aryl, 4-aryl, 5-aryl, 2
Nickel-catalyzed Suzuki-Miyaura couplings in green solvents
Ramgren, Stephen D.,Hie, Liana,Ye, Yuxuan,Garg, Neil K.
supporting information, p. 3950 - 3953 (2013/09/02)
The nickel-catalyzed Suzuki-Miyaura coupling of aryl halides and phenol-derived substrates with aryl boronic acids using green solvents, such as 2-Me-THF and tert-amyl alcohol, is reported. This methodology employs the commercially available and air-stable precatalyst, NiCl2(PCy 3)2, and gives biaryl products in synthetically useful to excellent yields. Using this protocol, bis(heterocyclic) frameworks can be assembled efficiently.
Photochemistry of N-isopropoxy-substituted 2(1H)-pyridone and 4-p-tolylthiazole-2(3H)-thione: Alkoxyl-radical release (spin-trapping, EPR, and transient spectroscopy) and its significance in the photooxidative induction of DNA strand breaks
Adam, Waldemar,Hartung, Jens,Okamoto, Hideki,Marquardt, Stefan,Nau, Werner M.,Pischel, Uwe,Saha-Moeller, Chantu R.,Spehar, Kristina
, p. 6041 - 6049 (2007/10/03)
UVA-irradiation of the photo-Fenton reagents N-isopropoxypyridone 2b and N-isopropoxythiazole2(3H)-thione 3b releases radicals which induce strand breaks. Transient spectroscopy establishes N-O bond scission [ΦN-O = (75 ± 8)% for 2b and (65 ± 7)% 3b] as the dominating primary photochemical process to afford the DNA-damaging radicals. Product studies and laser-flash experiments reveal that the thiazolethione 3b leads primarily to the disulfide 5, from which through C-S bond breakage, the bithiazyl 6, the thiazole 7, and the isothiocyanate 8 are derived. Upon irradiation of pyridone 2b (300 nm) in aqueous media, a mixture of isopropoxyl and 2-hydroxyprop2-yl radicals is formed, as confirmed by trapping with 5,5-dimethyl-1-pyrroline N-oxide (DMPO) and EPR spectroscopy. In contrast, the photolysis of the thiazolethione 3b (350 nm) affords exclusively the DMPO adducts of the isopropoxyl radicals. Control experiments disclose that the thiazolethione-derived photoproduct disulfide 5, or the intermediary thiyl radicals B, scavenge the carbon-centered 2-hydroxyprop-2-yl radicals, which are generated from the isopropoxyl radicals by hydrogen shift. With supercoiled pBR 322 DNA in a 60:40 mixture of H2O-MeCN, the pyridone 2b and the thiazolethione 3b display moderate strand-break activity (17% open-circular DNA for 2b and 12% for 3b). In pure water, however, the pyridone 2b photoinduces substantially more DNA cleavage (32% open-circular DNA), which is attributed to the peroxyl radicals generated from the 2-hydroxyprop-2-yl radicals by oxygen trapping. The lower strand-break activity of the thiazolethione 3b derives presumably from isopropoxyl radicals, because only these are detected in the photolysis of this photo-Fenton reagent.
