- General solution to the synthesis of N-2-substituted 1,2,3-triazoles
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The regioselective N-alkylation of 1,2,3-triazoles 1 - 6 was studied. Good to excellent N-2 selectivity and high chemical yields for N-2-substituted 4,5-dibromotriazoles 7 were obtained with 4,5-dibromo- and 4-bromo-5- trimethylsilyl-1,2,3-triazoles. These building blocks can be readily converted to 2-mono-, 2,4-di-, and 2,4,5-polysubstituted triazoles 10 - 15, providing a general, protective, group-free method for the synthesis of N-2-substituted triazoles. Observed regioselectivities can be rationalized by a combination of Frontier Molecular Orbital, steric, and electrostatic directing effects on the heterocyclic scaffolds.
- Wang, Xiao-Jun,Zhang, Li,Krishnamurthy, Dhileepkumar,Senanayake, Chris H.,Wipf, Peter
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scheme or table
p. 4632 - 4635
(2010/12/18)
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- Alkylation and acylation of the 1,2,3,triazole ring
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Trimethylsilylation of 1,2,3-triazole regioselectively proceeded to give 2-trimethylsilyl-2H-1,2,3-triazole, which was treated with primary alkyl halides in the presence of tetrabutylammonium fluoride to give 1-alkyl-1H- 1,2,3-triazoles as a Sole product 1-Methyl-5-substituted 1H-1,2,3-triazoles were prepared by alkylation of 5-lithio-1-methyl-1H-1,2,3-triazole, and 1- methyl-4-substituted 1H-1,2,3-triazoles were obtained by alkylation of 4- lithio-1-methyl-5-phenylthio-1H-1,2,3-triazole followed by reductive desulfurization.
- Ohta, Shunsaku,Kawasaki, Ikuo,Uemura, Takahiro,Yamashita, Masayuki,Yoshioka, Tomomichi,Yamaguchi, Satoshi
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p. 1140 - 1145
(2007/10/03)
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