- C?H Methylation of Iminoamido Heterocycles with Sulfur Ylides**
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The direct methylation of N-heterocycles is an important transformation for the advancement of pharmaceuticals, agrochemicals, functional materials, and other chemical entities. Herein, the unprecedented C(sp2)-H methylation of iminoamido heterocycles as nucleoside base analogues is described. Notably, trimethylsulfoxonium salt was employed as a methylating agent under aqueous conditions. A wide substrate scope and excellent level of functional-group tolerance were attained. Moreover, this method can be readily applied to the site-selective methylation of azauracil nucleosides. The feasibility of gram-scale reactions and various transformations of the products highlight the synthetic potential of the developed method. Combined deuterium-labeling experiments aided the elucidation of a plausible reaction mechanism.
- Ghosh, Prithwish,Kwon, Na Yeon,Kim, Saegun,Han, Sangil,Lee, Suk Hun,An, Won,Mishra, Neeraj Kumar,Han, Soo Bong,Kim, In Su
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supporting information
p. 191 - 196
(2020/10/29)
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- A Catalyst-Free Minisci-Type Reaction: the C–H Alkylation of Quinoxalinones with Sodium Alkylsulfinates and Phenyliodine(III) Dicarboxylates
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A direct C–H alkylation of quinoxalinones at the C-3 position with sodium alkylsulfinates and phenyliodine(III) dicarboxylates has been developed under catalyst-free conditions. A series of 3-alkylquinoxalinones were afforded in moderate to excellent yields in this protocol, which offers a practical and efficient access to biologically interesting 3-alkylquinoxalin-2(1H)-one derivatives.
- Wang, Liping,Zhao, Jiquan,Sun, Yuting,Zhang, Hong-Yu,Zhang, Yuecheng
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p. 6935 - 6944
(2019/11/11)
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- SYNTHESIS OF STABLE 3,6-EPIDIOXYPYRAZIN-2-ONES AND α-OXO IMIDES BY PHOTOOXYGENATION OF PYRAZIN-2-ONES WITH SINGLET OXYGEN
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Irradiation of the pyrazin-2-ones (1) in methanol under oxygen gave the 3,6-epidioxypyrazin-2-ones (2), the N-alkyl-N-acyl-α-oxo-amides (3), and the unusual products, N-alkyl-α-acyloxy-α-methoxy amides (4).The mechanism for the formation of these photoproducts is discussed.Furthermore, thermal or photochemical treatment of the 3,6-epidioxypyrazinones (2), which could be readily obtained by the reaction of (1) and singlet oxygen, gave the N-alkyl-N-acyl-α-oxo amides (3) and this reaction would provide a useful synthetic method for the α-oxo imides (3).
- Nishio, Takehiko,Tokunaga, Naoko (nee Nakajima),Kondo, Masaji,Omote, Yoshimori
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p. 2921 - 2926
(2007/10/02)
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