17228-64-7Relevant articles and documents
Reinvestigating catalytic alcohol dehydrogenation with an iridium dihydroxybipyridine catalyst
Brewster, Timothy P.,DeRegnaucourt, Alexa R.,Loadholt, Kylie H.,Papish, Elizabeth T.,Qu, Fengrui,Shrewsbury, Emily D.,Silprakob, Weerachai,Yao, Wenzhi
supporting information, p. 3656 - 3662 (2020/11/23)
The examined catalyst [Cp*Ir(H2O)(6,6′-dhbp)]2+ (1; 6,6′-dhbp = 6,6′-dihydroxy-2,2′-bipyridine) was reported in 2012 as a highly efficient (92% conversion) and selective catalyst for the conversion of benzyl alcohol to benzaldehyde as the sole product via acceptorless dehydrogenation. We report herein that the observed conversion and selectivity data are not accurate but may have resulted, in part, from other products being produced that are not easily detected. Specifically, benzoic acid is formed as a byproduct via the disproportionation of benzaldehyde, but at high temperatures, most of the benzoic acid produced is converted in situ to benzene and carbon dioxide. While we can explain the observed selectivity, we cannot explain the observed conversion to products. In our hands, we observed 15% conversion to products under the original conditions. Other alcohol substrates were also examined and gave lower conversion to products and decreased selectivity in comparison with the original report. Acceptorless alcohol dehydrogenation to generate aldehydes is a potentially transformative technology which can allow chemists to replace stoichiometric oxidants that produce waste with efficient catalysts that only generate H2 gas as a byproduct. Thus, clarification of the 2012 report to indicate what conditions can lead to high efficiency and selectivity is a worthy topic of discussion in the literature.
Preparation method of sodium 6-chloro-2-pyridol and 6-chloro-2-pyridone
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Paragraph 0017; 0018; 0019; 0020; 0021, (2018/05/16)
The invention relates to a preparation method of sodium 6-chloro-2-pyridol and 6-chloro-2-pyridone. 2,6-dichloropyridin is subjected to a substitution reaction with 2-methyl-2-butanol as a solvent anda catalyst under the strongly alkaline condition under the normal pressure in a reflux state. Tests prove that 2-methyl-2-butanol is the only alcohol as the solvent and the catalyst of the reaction,so that the preparation process of 6-chloro-2-pyridol or 6-chloro-2-pyridone is greatly simplified. Compared with the prior art, the preparation method adopts a simple, efficient and environment-friendly process.
Practical total syntheses of acromelic acids A and B
Inai, Makoto,Ouchi, Hitoshi,Asahina, Aya,Asakawa, Tomohiro,Hamashima, Yoshitaka,Kan, Toshiyuki
, p. 723 - 732 (2016/07/19)
Practical total syntheses of acromelic acids A (1) and B (2), which were scarce natural products isolated from toxic mushroom by Shirahama and Matsumoto, were accomplished in 13 (36% total yield) and 17 steps (6.9% total yield), respectively, from 2,6-dichloropyridine (8). Beginning with regioselective transformation of symmetric 8 by either ortho-lithiation or bromination, nitroalkenes 15 and 16 were provided. Stereoselective construction of the vicinal stereocenters at the C-3, 4 positions of 1 and 2 was performed by a Ni-catalyzed asymmetric conjugate addition of α-ketoesters to the nitroalkenes. Construction of the pyrrolidine ring was accomplished in a single operation via a sequence consisting of reduction of the nitro group, intramolecular condensation with the ketone, and reduction of the resulting ketimine.
