18791-75-8Relevant articles and documents
New method for promoting photosensitive oxidation to remove 1, 2-mercaptoethanol acetal protecting group by utilizing visible light irradiation
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Paragraph 0014-0016, (2021/01/30)
The invention discloses a new method for removing a 1, 2-mercaptoethanol acetal protecting group, and belongs to the field of organic synthetic chemistry. The method comprises the following steps of:under a room-temperature open system, adding a substrate 2-substituted-1, 3-oxo-thio-cyclopentane and a catalytic amount of a photosensitizer Eosin Y into a proper amount of acetonitrile; and performing irradiating with a blue LED lamp for 3 hours while stirring to obtain the corresponding aldehyde compound with favorable yield. The method has the advantages of mild operation conditions, greenness, environmental protection, no harsh water and oxygen removal operation and device, realization of the reaction at room temperature, high substrate conversion rate, simple and easy post-treatment, andprovides a good method for removing the 1, 2-mercaptoethanol acetal protecting group at present.
The catalytic behavior of heterocenes activated by TIBA and MMAO under a low Al/Zr ratios in 1-octene polymerization
Nifant'ev, Ilya E.,Vinogradov, Alexander A.,Vinogradov, Alexey A.,Churakov, Andrei V.,Bagrov, Vladimir V.,Kashulin, Igor A.,Roznyatovsky, Vitaly A.,Grishin, Yury K.,Ivchenko, Pavel V.
, p. 12 - 24 (2019/01/03)
A series of SiMe2-bridged ansa-zirconocenes LZrCl2 derived from heterocyclic ligands such as cyclopenta[1,2-b:4,3-b’]dithiophene, 5,6-dihydroindeno[2,1-b]indole and 5,10-dihydroindeno[1,2-b]indole, called “heterocenes” were synthesized and characterized by NMR spectroscopy and by X-ray diffraction analysis. These complexes were activated by triisobutylaluminium (TIBA) at AlTIBA/Zr ratio ～75 and then by MMАO-12 at AlMAO/Zr ratio ～10, and were studied in the polymerization of 1-octene in the absence or presence of molecular hydrogen. In the absence of molecular hydrogen, derivatives of cyclopenta[1,2-b:4,3-b’]dithiophene and dihydroindeno[2,1-b]indole demonstrated high catalytic activity, while dihydroindeno[1,2-b]indole complexes catalyzed slow polymerization with the formation of ultrahigh molecular weight poly(1-octene)s. In the presence of molecular hydrogen, derivatives of dihydroindeno[1,2-b]indole showed an order of magnitude increase in the catalytic activity. β-Hydride elimination, β-hexyl elimination and Zr-Al transfer were detected as the main chain release mechanisms depending on the nature of the ligand used. A novel chain termination with selective formation of –C(Me)=CHCH2– unsaturations was detected. It was found that heterocenes maintained a high catalytic activity up to 120 °C. Due to their high thermal stability and good hydrogen response, heterocenes are promising catalysts for the oligomerization and hydrooligomerization of α-olefins in the production of high-quality motor oil base stocks.
Oxidative Transformation of a Tetrathia S-Confused Isophlorin into Porphyrin Cation
Panchal, Santosh P.,Anand, Venkataramanarao G.
supporting information, p. 4854 - 4857 (2017/09/23)
The synthesis and redox properties of first generation S-confused isophlorins are described. Despite structural resemblance to a confused porphyrin, spectroscopic and computational studies reveal weak paratropic ring current effects in these 20π macrocycles. They display redox properties atypical of parent tetrathia isophlorins. Experimental evidence supports the oxidation of an unstable 19π neutral radical, as a transient intermediate, for the formation of a unique 18π aromatic monocationic species. Spectroscopic and structural characterization revealed the substituent dependent macrocycle oxidation unfamiliar to the chemistry of antiaromatic isophlorinoids.
