104086-41-1Relevant academic research and scientific papers
Thiopyrylium Cations as Appropriate Compounds for the Quantitative Evaluation of ipso-Substituent Effects
Doddi, Giancarlo,Ercolani, Gianfranco,Nunziante, Patrizia
, p. 1427 - 1430 (2007/10/02)
The kinetic and equilibrium constants for the reaction of 2,6-diphenyl-4-X-thiopyrylium cations (X = H, Ph, But, or OMe) with methoxide ion to yield the corresponding 2H- and 4H-adducts have been determined in MeOH at 25 deg C.The completion of
1H Nuclear Magnetic Resonance Study of Methoxide Addition to Pyrylium and Thiopyrylium Cations; Heteroatom and Substituent Effects
Doddi, Giancarlo,Ercolani, Gianfranco
, p. 271 - 276 (2007/10/02)
Methoxide addition to pyrylium and thiopyrylium salts with various α-substituents (Ph or tBu) and γ-substituents (H, Me, tBu, Et3C, Ph or MeO) in methanol at -40 and 25 deg C has been studied by 1H n.m.r.The composition of the product mixtures, kinetically controlled at -40 deg C and thermodynamically controlled at 25 deg C, gives information on the factors affecting positional selectivity and the relative thermodynamic stability of the addition products (the 2H- and 4H-adduct).The methyl-substituted substrates also undergo deprotonation, to yield the corresponding anhydro-bases.Analysis of heteroatom and substituent effects on the rean course emphasizes the role of polar and steric interactions, and sheds light on the structures of the transition states.
