- A novel strategy for developing yellow diarylethenes based on acid stimulus
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A novel strategy for the preparation of yellow diarylethenes was established based on the acidichromism of two new diarylethenes with a bromopyridine moiety. The bromopyridine was connected directly to the central perfluorocyclopentene ring to participate in photoisomerization reaction. The two diarylethenes exhibited favorable photochromism and function as notable fluorescence switches in solution. The absorption maxima of their closed-ring isomers shifted dramatically to shorter wavelengths with notable color change from red to yellow upon the stimulation of trifluoroacetic acid.
- Zheng, Chunhong,Pu, Shouzhi,Liu, Gang,Chen, Bing
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- 2,6-Dibromo-3,5-dimethylpyridine and 2,6-diiodo-3,5-dimethylpyridine
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The title compounds 2,6-dibromo-3,5-dimethylpyridine, C7H 7Br2N, (I), and 2,6-diiodo-3,5-dimethylpyridine, C 7H7I2N, (II), constitute the first structurally characterized examples of 2,6-dihalo-3,5-dimethylpyridines. Compound (I) crystallizes as a racemic twin with two symmetry-independent molecules in the asymmetric unit, while (II) is non-planar with the pyridine ring slightly deformed into a saddle shape, and exhibits crystallographically imposed twofold symmetry. Both (I) and (II) exhibit aromatic face-to-face π-stacking in the solid state, although there are no other long-range interactions. In (I), alternate molecules are oriented at 90°, resulting in X-shaped columns, while in (II), molecules pack in a parallel fashion, leading to a zigzag array.
- Pugh, David
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- A sensitive sensor for Cu(II) based on a novel diarylethene with a bipyridyl moiety
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A novel diarylethene with a bipyridyl unit has been designed and synthesized for the first time. Its photochromic behaviors could be modulated by protonation and coordination with Cu(II). The absorption maximum of the closed-ring isomer shifted from 569 to 666 nm when trifluoroacetic acid was added. Furthermore, the closed-ring isomer behaved as a sensitive colorimetric sensor, exhibiting an open-ring reaction upon exposure to Cu(II). Its high selectivity toward Cu(II) over other competitive species makes the 'naked-eye' detection of Cu(II) possible.
- Zheng, Chunhong,Liu, Gang,Pu, Shouzhi
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- Highly Selective Binding and Inhibition of Pyr-His-Pro-NH2 (TRH) Function using a Polypyridinyl Macrocyclic Receptor with an Amphiphilic Cavity
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Macrocycle, cyclo[4] [(1,3-(4,6)-dimethylbezene)[4](2,6-(3,5)-dimethylpyridine (B4P4), shows highly selective binding affinity with protirelin (Pyr-His-Pro-NH2; TRH) among the tested 26 drug or drug adductive substrates. The stable complexation in a 1:1 manner was fully characterized in solution, gas phase, and solid state study. Furthermore, B4P4 acts as an efficient TRH inhibitor even at [macrocycle]:[drug] 1:300, both in membrane transport and cellar incubation. The current work provides an unprecedented strategy for macrocycles to be efficiently used in drug target therapy.
- Hou, Chao-Ping,Yang, Jian,Zhang, Lei,Ma, Zhen-Hua,Li, Qian,Xiang, Jun-Feng,Gong, Han-Yuan
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- Synthesis method of 3,5-dimethyl-2,6-dibromopyridine
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The invention relates to the field of organic chemistry and particularly relates to a synthesis method of 3,5-dimethyl-2,6-dibromopyridine. The synthesis method comprises the steps of (1) adopting 3,5-dimethyl-2-aminopyridine as a raw material, adding the 3,5-dimethyl-2-aminopyridine and acetic anhydride to a four-mouth flask, raising the temperature until refluxing, and carrying out thin-layer chromatography tracking reaction; (2) when the temperature of a reaction liquid in the step (1) is reduced to below 23 DEG C, dropwise adding liquid bromine, reacting at 40-55 DEG C for 2-3h after dropwise adding, adding water to the system until all solids are dissolved, dropwise adding a sodium hydroxide solution, generating a lot of sediments and further reacting for 20-40min, carrying out suction filtration, drying and recrystallizing to obtain 3,5-dimethyl-2-amino-6-bromopyridine; and (3) adding the 3,5-dimethyl-2-amino-6-bromopyridine to a hydrogen bromide solution, dropwise adding a saturated sodium nitrite solution in the presence of a catalytic amount of cuprous bromide, controlling the temperature to be -3 DEG C to -4 DEG C and reacting for 2-3h to obtain the 3,5-dimethyl-2,6-dibromopyridine. The method is mild in reaction condition, high in yield, available in raw material, relatively low in cost and short in process route.
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Paragraph 0018; 0020; 0021; 0023; 0024; 0026
(2017/10/13)
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- Effects of the peripheral heteroaryl substituents on the photochromism of new pyridine-containing diarylethenes
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Three new unsymmetrical pyridine-containing diarylethenes with a variable peripheral heteroaryl unit were synthesized and their structures were determined by single-crystal X-ray diffraction analysis. The substituent effects of variable heteroaryl groups on the photochromic and fluorescence properties were systematically discussed. Thienyl and thiazyl could effectively enhance the cyclization quantum yields and photoconversion ratios in the photostationary state, as compared to the phenyl group. However, they had no obvious effect on the fluorescence behaviors. Moreover, X-ray structural analysis revealed that the N?S heteroatom-contact interactions resulted in a higher cyclization quantum yield, which may be ascribed to the effective stabilizing ability on the photoreactive formations in diarylethenes with a thienyl/thiazyl unit.
- Liao, Guanming,Xue, Dandan,Zheng, Chunhong,Wang, Renjie,Pu, Shouzhi
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p. 1989 - 1997
(2016/11/03)
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