6638-95-5Relevant academic research and scientific papers
Iminium Salts in Solid-State Syntheses Giving 100% Yield
Kaupp, Gerd,Schmeyers, Jens,Boy, Juergen
, p. 269 - 280 (2007/10/03)
Numerous reaction types in the field of iminium salts are performed in the gas-solid and solid-solid techniques in order to reach 100% yield. The stoichiometric runs are waste-free and do not require costly workup. Frequently, iminium salts were avoided, as acid catalysis was dispensable. Thioureas and α-halogenated ketones give a variety of 2-aminothiazoles via thiuronium salts in quantitative yield. A new intramolecular solid-state thermal condensation is reported. Enaminoketones are synthesized quantitatively from anilines and 1,3-diketones without catalysis and those can be used for quantitative solid-state 4-cascade reactions. Solid paraformaldehyde is used to produce methylene imines and internally trapped methylene iminium salts. Benzoylhydrazones are produced again without catalysis in the solid state. Vacuum and ball-mill techniques are particularly useful in the production of highly sensitive iminium salts. Hexahydro-1,3,5-triazines cyclorevert upon exposure to HCl gas to give solid arylmethylene iminium chlorides as new versatile reagents. These are used in arylaminomethylations of β-naphthol and of themselves to give Troeger's bases in 3-cascades. More direct are 4-cascade Troeger's base syntheses by dissolving hexahydro-1,3,5-triaryltriazines in trifluoroacetic acid. Alkylations of imines with trimethyloxonium tetrafluoroborate and triphenylmethyl cation give highly sensitive quaternary iminium salts in the ball-mill. The products are characterized by spectroscopic techniques and density functional theory (DFT) calculations at the B3LYP 6-31G* level. Molecular movements in the crystal and surface passivation are investigated with atomic force microscopy (AFM) techniques.
A General and Practicable Synthesis of Polycyclic Heteroaromatic Compounds. Part 4. A Rationale for the Mechanism of the Synthesis
Asherson, Janet L.,Bilgic, Orhan,Young, Douglas W.
, p. 3041 - 3047 (2007/10/02)
Studies on aspects of the mechanism of our general synthesis of polycyclic heteroaromatic compounds suggest that the reaction sequence outlined in Scheme 2 is followed.Under the conditions of our synthesis, the ortho-rearrangement (8) --> (9) is preferred to the para-rearrangement which is known to occur in acid conditions.Aniline Mannich bases (29) are converted to benzacridines (30) in an intermolecular reaction.The synthesis appears to be restricted to substrates where the putative intermediate (9) is not part of an amide group.In the course of these studies effective syntheses of the tricyclic compounds (24) and (25) have been discovered.
