59104-31-3Relevant academic research and scientific papers
Hydrogen-bonding thiourea organocatalysts: The privileged 3,5-bis(trifluoromethyl)phenyl group
Lippert, Katharina M.,Hof, Kira,Gerbig, Dennis,Ley, David,Hausmann, Heike,Guenther, Sabine,Schreiner, Peter R.
, p. 5919 - 5927 (2013/01/15)
We present evidence that the privileged use of the 3,5-bis(trifluoromethyl) phenyl group in thiourea organocatalysis is due to the involvement of the ortho-CH bond in the binding event with Lewis-basic sites. We utilized a combination of low-temperature IR spectroscopy, 2D NMR spectroscopy, nano-MS (ESI) investigations, as well as density functional theory computations [M06/6-31+G(d,p), including solvent corrections as well as natural bond orbital and atoms-in-molecules analyses] to support our conclusions that bear implications for catalyst design. The present work reveals that thiourea derivatives bearing a 3,5-bis(trifluoromethyl)phenyl group interact with Lewis basic sites of carbonyl derivatives through NH and highly polarized ortho-CH interactions in hydrogen-bonded complexes. Evidence is provided through a combination of DFT, variable-temperature IR and NMR spectroscopy, as well as MS (ESI) studies.
Synthesis and conformational features of sym N,N′,N″- triarylguanidines
Gopi, Kanniyappan,Rathi, Brijesh,Thirupathi, Natesan
experimental part, p. 157 - 167 (2010/11/17)
A one pot reaction involving sym N,N′-diarylthiourea and the respective arylamine in the presence of aq. KOH in nitrobenzene at ≥105°C afforded sym N,N′,N″-triarylguanidine in fair to good yield and the products have been characterized. Sym N,N′,N″-tri(4-tolyl)guanidine possesses (7) anti-anti conformation, sym N,N′,N″-tri(2-tolyl) guanidine (8) and sym N,N′,N″-tris(2,4-xylyl)guanidine (11) each possess anti-anti αβα conformation whereas sym N,N′,N″-tris(2-anisyl)guanidine possesses (9) syn-anti αββ conformation as determined by single crystal X-ray diffraction data. The observed conformations appear to result from a subtle balance between steric factor associated with the aryl substituent and multiple electronic factors namely n-π conjugation/negative hyperconjugation and non-covalent interactions in the crystal lattice. Indian Academy of Sciences.
