66529-43-9Relevant academic research and scientific papers
Effect of Bronsted Acids and Bases, and Lewis Acid (Sn2+) on the Regiochemistry of the Reaction of Amines with Trifluoromethyl-β-diketones: Reaction of 3-Aminopyrrole to Selectively Produce Regioisomeric 1H-Pyrrolo[3,2-b]pyridines
De Rosa, Michael,Arnold, David,Hartline, Douglas,Truong, Linda,Verner, Roman,Wang, Tianwei,Westin, Christian
, p. 12288 - 12299 (2015)
Reaction of 3-aminopyrrole (as its salt) with trifluoromethyl-β-diketones gave γ-1H-pyrrolo[3,2-b]pyridines via reaction at the less reactive carbonyl group. The trifluoromethyl group increased the electrophilicity of the adjacent carbonyl group and decreased the basicity of the hydroxyl group of the CF3 amino alcohol formed. This amino alcohol was formed faster, but its subsequent dehydration to the β-enaminone was slow resulting in the preferential formation of the γ-regioisomer. Reaction of 4,4,4-trifluoro-1-phenyl-1,3-butadione with 3-aminopyrrole was carried out using a series of 6 amine buffers. Yields of the α-1H-pyrrolo[3,2-b]pyridine increased as the pKa of the amine buffer decreased. Surprisingly the yield went down at higher pKas. There was a change in mechanism as the reaction mixture became more basic. With strong amines trifluoromethyl-β-diketones were present mainly or completely as the enolate. Under reductive conditions (3-nitropyrrole/Sn/AcOH/trifluoromethyl-β-diketone) the α-1H-pyrrolo[3,2-b]pyridine was the major product as a result of Lewis acid catalysis by Sn2+. Similar α-regiochemistry was observed when the reaction of the 3-aminopyrrole salt with trifluoromethyl-β-diketones was carried out in the presence of base and tin(II) acetate.
The preparation and properties of some tetracoordinate boron compounds. The pseudo-metal ion concept
Toporcer,Dessy,Green
, p. 1649 - 1655 (2007/10/05)
The infrared, ultraviolet, H1 and B11 nuclear magnetic resonance spectra, and polarographic behavior of a series of R2B complexes possessing tetrahedral geometry indicate that they and similar derivatives can serve as excellent models with which to study chelate characteristics. The R2B moiety functions as a pseudo-metal ion or atom which permits alteration of total and effective charge without variation in size of the chelate ring and permits placement and surveying of probes to study the electron distribution in the chelates.
