Synthesis of Bis(amino)pyridines by the Stepwise Alkylation of Bis(imino)pyridines: An Unexpected and Selective Alkylation of the Aminoiminopyridine by AlMe3

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• 作者：Boon-Ying Tay ; Cun Wang ; Sze-Chen Chia ; Ludger P. Stubbs ; Pui-Kwan Wong ; Martin van Meurs
• 刊名：Organometallics
• 出版年：2011
• 出版时间：November 14, 2011
• 年：2011
• 卷：30
• 期：21
• 页码：6028-6033
• 全文大小：359K
• 年卷期：v.30,no.21(November 14, 2011)
• ISSN：1520-6041

文摘

Bis(imino)pyridines 2-[2,6-(Rp>1p>)₂C₆H₃N鈺怌(CH₃)]-6-[2,6-(Rp>2p>)₂C₆H₃N鈺怌(CH₃)](C₅H₃N) (1a, Rp>1p> = Rp>2p> = i-Pr; 1b, Rp>1p> = i-Pr, Rp>2p> = CH₃; 1c, Rp>1p> = Rp>2p> = CH₃) were first alkylated by AlMe₃ and then hydrolyzed to aminoiminopyridines 2-[2,6-(Rp>1p>)₂C₆H₃N鈺怌(CH₃)]-6-[2,6-(Rp>2p>)₂C₆H₃NHC(CH₃)₂](C₅H₃N) (3a, Rp>1p> = Rp>2p> = i-Pr; 3b, Rp>1p> = i-Pr, Rp>2p> = CH₃; 3c, Rp>1p> = Rp>2p> = CH₃). When the aminoiminopyridines were treated with AlMe₃, the expected methane elimination was not found; alkylation at the imine functional group led to the aluminum complexes {2-[2,6-(Rp>1p>)₂C₆H₃NC(CH₃)₂]-6-[2,6-(Rp>2p>)₂C₆H₃NHC(CH₃)₂](C₅H₃N)}AlMe₂ (4a, Rp>1p> = Rp>2p> = i-Pr; 4b, Rp>1p> = i-Pr, Rp>2p> = CH₃; 4c, Rp>1p> = Rp>2p> = CH₃), which were further hydrolyzed to the bis(amino)pyridines 2-[2,6-(Rp>1p>)₂C₆H₃NHC(CH₃)₂]-6-[2,6-(Rp>2p>)₂C₆H₃NHC(CH₃)₂](C₅H₃N) (5a, Rp>1p> = Rp>2p> = i-Pr; 5b, Rp>1p> = i-Pr, Rp>2p> = CH₃; 5c, Rp>1p> = Rp>2p> = CH₃). The selective alkylation over elimination may come from the noninnocent property of the conjugated iminopyridine group. New magnesium, yttrium, and zirconium complexes supported by 5a ({2,6-[2,6-(i-Pr)₂C₆H₃NC(CH₃)₂]₂(C₅H₃N)}Mg(THF) (6), {2,6-[2,6-(i-Pr)₂C₆H₃NC(CH₃)₂]₂(C₅H₃N)}Y(CH₂SiMe₃)(THF) (7), and {2,6-[2,6-(i-Pr)₂C₆H₃NC(CH₃)₂]₂(C₅H₃N)}Zr(CH₂SiMe₃)₂ (8)) were formed via the alkane elimination method.