Darstellung einiger substituierter Triphthaloyl-benzole als Ausgangsmaterialien für grüne Küpenfarbstoffe
作者:H. E. Fierz-David、L. Blangey、W. Von Krannichfeldt
DOI:10.1002/hlca.19470300317
日期:1947.4.30
Durch Kondensation entsprechend substituierter 1,4-Naphtho-chinone mittels Pyridin wurden das α-Trichlor-, α, α′-Hexachlor-, α- und β-Triacetamino- sowie das β-Trimethoxy-triphthaloyl-benzol neu hergestellt.
compound, i.e., 2-iodobenzoic acid (2-IB), selectively yields p-quinones from monomethoxyarenes under mild conditions. In this reaction system, an organoiodine compound is immediately oxidized by Oxone® to generate cyclic hypervalent iodine (III) species in situ, which serves as the specific mediator for the selective p-quinone synthesis, preventing o-quinone formation.
Quinine-catalyzed enantioselective tandem conjugate addition/intramolecular cyclization of malononitrile and 1,4-dien-3-ones
作者:Zhi-Peng Hu、Jian Li、Xiao-Gang Yin、Xue-Jing Zhang、Ming Yan
DOI:10.3998/ark.5550190.0014.301
日期:——
An organocatalytic tandemconjugateaddition / intramolecularcyclization of malononitrile and conformationally restricted 1,4-dien-3-ones has been developed. A series of cinchona alkaloids and their derivatives were examined as the catalysts. Quinine was found to be the most efficient catalyst in the absence of any additive. The reaction gave 2-amino-4H-pyrans with high yield and excellent enantiopurity
It has been shown by a series of experiments on 5-alkyl, 5-halo-, and other 5-substituted 1-naphthol derivatives that the product ratio of the ortho- and para-naphthoquinones formed on oxidation with Fremy's salt is controlled by the bulkiness of the C5-substituent.