22114-38-1Relevant articles and documents
2-Arylvinylpyrimidines versus 4-arylvinylpyrimidines: Synthesis and comparison of the optical properties
Achelle, Sylvain,Robin-Le Guen, Fran?oise
, p. 4491 - 4496 (2013)
Condensation of donor-substituted aldehydes on methylpyrimidine led to two series of fluorescent molecules depending on the position of the methyl group. Whereas highly emissive 4-arylvinylpyrimidine derivatives are well-known, this is the first example of fluorescent 2-arylvinylpyrimidine compounds. The optical properties of the two families have been thoroughly compared. Whereas the series derived from 2-methylpyrimidine exhibit a blue shift in absorption and emission in comparison with 4-arylvinylpyrimidine, the influence of the position is less predictable on the fluorescence quantum yield. These compounds also exhibit halochromism: when adding acid, a bathotromic shift is observed in absorption whereas an increase of the fluorescence intensity which is red-shifted except for amino derivatives (a progressive quench of emission is observed in these cases). An emission solvatochromism study has shown that a higher intramolecular charge transfer seems to occur in 2-arylvinylpyrimidines than in 4-arylvinylpyrimidines.
A novel tautomerism in alkyl dihydropyrimidines: Observation of tautomerism by H-D exchange of 2- and/or 4-methyl protons of dihydropyrimidines in CD3OD
Kim, Yong Hae,Lim, Byoung Uk
, p. 2057 - 2060 (1991)
A novel tautomerism was found in dihydropyrimidines such as 2-amino-4,6,6-trimethyldihydropyrimidine 1 and 2,4,6,6-tetramethyldihydropyrimidine 2 by the observation of H-D exchange on both 4-methyl protons of 1 and 2,4-dimethyl protons of 2 by the treatme
Mechanistic insight into the azo radical-promoted dehydrogenation of heteroarene towards N-heterocycles
Bains, Amreen K.,Adhikari, Debashis
, p. 6309 - 6318 (2020/11/03)
Borrowing hydrogenation-promoted annulations are considered to be important reactions to synthesize wide variety of N-heterocycles. In these processes, the dehydrogenation of saturated heteroarenes in the late stage is generally required to furnish the desired N-heterocycle. However, in a one-pot, multistep heterocycle synthesis, this step is not well elucidated, and the role of the catalyst is not thoroughly understood. Furthermore, the use of copious amount of base at elevated temperatures further complicates this matter and casts doubt on the involvement of the catalyst in heteroarene dehydrogenation. Herein, we report a molecularly defined nickel catalyst, which can perform two annulation reactions under mild conditions (80 °C, 8 h), towards the sustainable synthesis of triazine and pyrimidine. Mechanistically, we clearly describe the important role of the catalyst in promoting the dehydrogenation of heteroarenes. The binding of the saturated heterocycle to the metal catalyst undergoes a pre-equilibrium step (K = 238 at 80 °C), which is followed by a crucial hydrogen atom transfer. A series of kinetics experiments including Van't Hoff, Eyring analysis and interception of pyrimidinyl radical disclosed the details of the dehydrogenation process. This ligand-driven, base metal catalytic approach is significantly different from the considerably evaluated metal-ligand cooperative bond activation strategies, which may offer an alternative dehydrogenation pathway that demands less energy. This journal is
Cooperative ruthenium complex catalyzed multicomponent synthesis of pyrimidines
Maji, Milan,Kundu, Sabuj
supporting information, p. 17479 - 17487 (2019/12/23)
A new set of 2-(2-benzimidazolyl) pyridine ligand based air and moisture stable ruthenium complexes were synthesized and characterized. The catalytic behaviors of these complexes were evaluated towards the multicomponent synthesis of highly substituted py
