Inexpensive Radical Methylation and Related Alkylations of Heteroarenes
作者:Qi Huang、Samir Z. Zard
DOI:10.1021/acs.orglett.8b00190
日期:2018.3.2
A simple method for the introduction of a methyl and higher aliphatic group to various heteroarenes using very inexpensive reagents is described. It is based on the radical addition of a carboxylic xanthate followed by decarboxylation. Depending on the heteroarene structure, the decarboxylation can be spontaneous or induced by heating in N,N-dimethylacetamide or N-methyl pyrrolidone in a microwave
Quinoxalines. XXVI. Reactions of 2-quinoxalinyl thiocyanate with nucleophiles.
作者:Chihoko IIJIMA、Tomiko KYO
DOI:10.1248/cpb.37.618
日期:——
2-Quinoxalinyl thiocyanate (1) possesses four electrophilic sites, i.e., 2-position, 3-position, sulfur and cyano carbon, to receive nucleophilic attack.Grignard reagents attacked preferentially the sulfur atom to give sulfides (8-12).These sulfides were readily oxidazed to sulfoxides (13-17) with sodium bromite in acetic acid.Hydroxide and ethoxide ions were found to attack preferably the cyano carbon to give thiol (2), while amines (butylamine, piperidine and morpholine) and ethyl cyanoacetate carbanion attacked the carbon at the 2-position to afford the corresponding ipso-substitution products (4-7).
Abstract Newquinoxalinederivatives were prepared by the reaction of 2-hydroxyquinoxaline 1 and alkyl or alkylaminoalkyl halides in dimethylformamide using potassium carbonate as a base. The hydroxyl group was readily converted into a thiol function by treatment with phosphorus pentasulfide and/or Lawesson's reagent in pyridine, and the subsequent alkylation of the thiol group was carried out under
Efficient Synthesis of Quinoxaline Derivatives by Selective Modification of 3-Chloro-6-fluoroquinoxalin-2(1<i>H</i>)-one 4-Oxide
作者:Jan Maichrowski、Mimoza Gjikaj、Eike G. Hübner、Bärbel Bergmann、Ingrid B. Müller、Dieter E. Kaufmann
DOI:10.1002/ejoc.201201569
日期:2013.4
The readily available and polyfunctionalized 3-chloro-6-fluoroquinoxalin-2(1H)-one4-oxide, derived from the efficient one-step annulation reaction of 1,1,2-trichloro-2-nitroethene with 4-fluoroaniline, was selectively modified at the chloronitrone and the amide units, leading to more than 30 new quinoxalinederivatives with a unique substitution pattern in good to excellent yields. In addition, the
Phenanthrenequinone (PQ) catalyzed cross-dehydrogenative coupling of alkanes with quinoxalin-2(1<i>H</i>)-ones and simple N-heteroarenes under visible light irradiation
作者:Min Wang、Yicheng Zhang、Xinyu Yang、Peipei Sun
DOI:10.1039/d2ob00278g
日期:——
A convenient strategy for alkylation of quinoxalin-2(1H)-ones and other N-heterocycles with simple alkanes using phenanthrenequinone (PQ) as a photocatalyst has been developed.