The Journal of Organic Chemistry

Electrophilic aromatic substitution. 26. Regioselective halo-and carbodesilylation of (trimethylsilyl)-1-methylpyrazoles

F Effenberger, A Krebs

Index: Effenberger, Franz; Krebs, Andreas Journal of Organic Chemistry, 1984 , vol. 49, # 24 p. 4687 - 4695

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Citation Number: 39

Abstract

The isomeric 3-, 4-, and 5-(trimethylsily1)-as well as the 3, 4-, 3, 5-, and 4, 5-bis (trimethylsilyl)-l-methylpyrazoles (2, 7, 3, 5, 9, and 10, respectively) are obtained by methylation of the corresponding (trimethylsily1)-1H-pyrazoles or by silylation of Grignard or lithio derivatives of appropriate 1-methylpyrazoles with chlorotrimethylsilane. 5 and 10 are halodesilylated regioselectively by Br2 or IC1 in the 4-position, yielding 13 and 15. With ...