25827-94-5Relevant articles and documents
Selective synthesis of oxazoles and pyrazines from α-bromo-1-phenylethanone using a by-product-promoted strategy
Liu, Changhui,Zhao, Jiateng,Qiao, Yu,Huang, Wenbo,Rao, Zhonghao,Gu, Yanlong
, p. 7351 - 7357 (2018/11/23)
Oxazoles and pyrazines are fundamental heterocycles that widely found in natural products or drugs. In this work, a selective strategy for oxazoles and pyrazines synthesis using α-bromo-1-phenylethanone and ammonium acetate as starting materials was reported. This methodology features mild reaction conditions, readily accessible starting materials and good chemoselectivity. Mechanistic study indicates that this reaction involves a by-product-promoted (BPP) process for the formation of oxazole, that is, the in-situ formed hydrogen bromide (HBr) during the reaction promotes the whole tandem process.
Switchable Synthesis of Pyrroles and Pyrazines via Rh(II)-Catalyzed Reaction of 1,2,3-Triazoles with Isoxazoles: Experimental and DFT Evidence for the 1,4-Diazahexatriene Intermediate
Rostovskii, Nikolai V.,Ruvinskaya, Julia O.,Novikov, Mikhail S.,Khlebnikov, Alexander F.,Smetanin, Ilia A.,Agafonova, Anastasiya V.
, p. 256 - 268 (2017/04/26)
4-Aminopyrrole-3-carboxylates and pyrazine-2-carboxylates were synthesized from 5-alkoxyisoxazoles and 1-sulfonyl-1,2,3-triazoles by tuning the Rh(II) catalyst and the reaction conditions. The reaction in chloroform at 100 °C under Rh2(OAc)4 catalysis provides 4-aminopyrrole-3-carboxylates in good yields. The use of Rh2(Piv)4 in refluxing toluene results in the formation of 1,2-dihydropyrazine-2-carboxylates as the main products, which can be converted by a one-pot procedure to pyrazine-2-carboxylates by heating with catalytic amounts of TsOH. According to the NMR and DFT investigations of the reaction mechanism, pyrroles and dihydropyrazines are formed, respectively, via 1,5- and 1,6-cyclization of common (5Z)-1,4-diazahexa-1,3,5-triene intermediates. The influence of the nature of the catalyst on the product distribution is rationalized in terms of the Rh-catalyzed isomerization of a pyrrolin-2-ylium-3-aminide zwitterion, the primary product of 1,4-diazahexatriene 1,5-cyclization.
A general catalyst for Suzuki-Miyaura and Sonogashira reactions of aryl and heteroaryl chlorides in water
Peng, Hui,Chen, Ya-Qin,Mao, Shu-Lan,Pi, Yun-Xiao,Chen, You,Lian, Ze-Yu,Meng, Tong,Liu, Sheng-Hua,Yu, Guang-Ao
supporting information, p. 6944 - 6952 (2014/09/29)
We report the synthesis of 2-(3-sulfonatomesityl)-5-sulfonatoindenyl) dicyclohexylphosphine hydrate sodium salt and its use in palladium-catalyzed Suzuki-Miyaura and Sonogashira coupling reactions in water (and biphasic water-organic solvent mixtures) to prepare a variety of functionalized biaryls and aryl alkynes in excellent yield. This journal is the Partner Organisations 2014.
