53103-82-5Relevant academic research and scientific papers
3,4-Dihydro-2H-pyran promoted aerobic oxidative aromatization of 1,3,5-trisubstituted pyrazolines and Hantzsch 1,4-dihydropyridines
Banerjee, Dipanwita,Kayal, Utpal,Karmakar, Rajiv,Maiti, Gourhari
supporting information, p. 5333 - 5337 (2015/01/08)
An unprecedented facile oxidation of 1,3,5-trisubstituted pyrazolines and Hantzsch 1,4-dihydropyridines (DHPs) to the corresponding pyrazoles and pyridines was observed, mediated by 3,4-dihydro-2H-pyran in air. The reaction showed excellent reactivity, functional group tolerance, and high yield without using any metal and/or halogen based oxidizing agents.
Oxidative addition of N-aminophthalimide to alkenyl-4,5-dihydropyrazoles and alkenylpyrazoles. Synthesis of aziridinylpyrazoles
Ignatenko,Blandov,Kuznetsov
, p. 1793 - 1801 (2007/10/03)
Oxidation of N-aminophthalimide with lead tetraacetate in the presence of 1,5-diaryl-3-[(E)-2-arylethenyl]-1H-pyrazoles, as well as of 1,3-diphenyl-5-[(E)-2-phenylethenyl]-1H-pyrazole, gives adducts at the exocyclic C=C bond, the corresponding phthalimidoaziridinylpyrazoles. From 1,5-diphenyl-3-[(1E,3E)-4-phenyl-1,3-butadienyl]-1H-pyrazole, only product of addition at both exocyclic C=C bonds was obtained. In the reaction with 1-phenyl-3-[(1E,3E)-4-phenyl-1,3-butadienyl]-5-[(E)-2-phenylethenyl] -1H-pyrazole, the adduct at the styryl C=C bond was isolated. Analogous 4,5-dihydropyrazoles, 1,5-diphenyl-3-[(1E,3E)-4-phenyl-1,3-butadienyl]-4,5- dihydro-1H-pyrazole and 1-phenyl-3-[(1E,3E)-4-phenyl-1,3-butadienyl]-5-[(E)-2- phenylethenyl]-4,5-dihydro-1H-pyrazole, turned out to be inert in oxidative addition of N-aminophthalimide.
Quenching of Singlet Oxygen by 1,3,5-Triaryl-2-pyrazolines
Ando, Wataru,Sato, Rikiya,Yamashita, Masataka,Akasaka, Takeshi,Miyazaki, Hajime
, p. 542 - 546 (2007/10/02)
The efficient quenching of photochemically generated singlet oxygen by four 1,3,5-triaryl-2-pyrazolines (5-8) and p-(diethylamino)benzaldehyde diphenylhydrazone (9) has been investigated by inhibition of the photosensitized oxygenation of 1,3 diphenylisobenzofuran and 2-methyl-2-pentene. 1-Phenyl-3--5--2-pyrazoline (8) quenches singlet oxygen without any reaction at all, and the quenching rate constant reaches a maximum of 5.8 x 109 M-1 s-1.The quenching ability correlates with the value of their one-electron oxidation potentials (Ep).
