33288-76-5Relevant articles and documents
Solvent effect on the sensitized photooxygenation of cyclic and acyclic α-diimines
Lemp, Else,Zanocco, Antonio L.,Günther, German,Pizarro, Nancy
, p. 10734 - 10746 (2006)
The reaction of singlet molecular oxygen with a series of cyclic and acyclic α-diimines was studied. Time-resolved methods were used to measure total reaction rate constants and steady-state methods were used to determine chemical reaction rate constants. GC-MS was used to tentatively assign the reaction products. 5,6-Disubstituted cyclic α-diimines are singlet oxygen quenchers, but become more effective in polar solvents. A reaction mechanism involving a perepoxide intermediate or transition state leading to a hydroperoxide seems to be a key reaction path for product formation. A replacement of the phenyl substituent for a methyl substituent opens up an additional reaction involving a perepoxide-like exciplex, which increases singlet oxygen quenching of the cyclic α-diimines. The reactivity of 5,6-disubstituted cyclic α-diimines towards singlet oxygen is highly dependent on steric interactions arising from vicinal phenyl rings and from electronic effects. 1,4-Disubstituted acyclic α-diimines are, by comparison, moderate or poor singlet oxygen quenchers. Total rate constants are scarcely dependent on solvent properties, but instead correlate with the Hildebrand parameter. These results are explained in terms of a mechanism involving a dioxetane-like exciplex that gives rise to a charged intermediate leading to products.
Synthetic method of quinoxaline heterocyclic compound
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Paragraph 0025; 0026, (2016/10/09)
The invention provides a synthetic method of a quinoxaline heterocyclic compound. A quinoxaline heterocyclic derivative is prepared through one step by carrying out oxidation and cyclic condensation reaction on benzoin and ortho-diamine under the catalysis of a non-transition metal catalyst. According to the method, low-price and easily-available benzoin is used as a raw material, a water-soluble non-transition metal is used as a catalyst and convenient, economical and safe air is used as a direct oxidant to synthesize a target heterocyclic compound through one step at room temperature or a temperature slightly higher than the room temperature; the reaction condition is simple and mild; and inert gas protection is not needed as the synthesis is carried out in the air. The method is easy to operate, the only byproduct is water, the product is simple and easy to separate and purify, the yield is high, and the reaction condition requirement is relatively low, so that the method is wide in application range and has good research and industrial application prospects.
Iodine-mediated efficient synthesis of 2,3-dihydro-pyrazines
Dong, Yansheng,Huang, Li,Yi, Fengping
, p. 430 - 432 (2015/08/24)
The synthesis of 2,3-dihydro-pyrazines has been developed by an efficient protocol of annulations of 1,2-diketones and ethylenediamine. A variety of 2,3-dihydro-pyrazines were prepared in high yields in the presence of a catalytic amount of iodine.
