262855-01-6Relevant articles and documents
Diaminosilane-functionalized on silicate-stabilised hydrotalcite (MA-HTSi-DA): As potential catalyst for nitro-aldol condensation
Thangaraj, Baskaran,Jayaraj, Christopher,Srinivasan, Radhakrishnan,Ayyamperumal, Sakthivel
, p. 11 - 18 (2015)
Diaminosilane was introduced into silicate-anion-intercalated hydrotalcite (HT-Si) using a post-synthesis method. The resulting functionalized materials possess surface basicity. The textural properties of the functionalized materials were systematically investigated through powder XRD, FTIR and MAS-NMR studies. The diamine-functionalized materials showed very good catalytic activity for the nitro-aldol condensation of benzaldehyde and nitromethane under solvent-free conditions. The materials showed comparable catalytic activity upon recycling.
One-Pot Enzyme Cascade Catalyzed Asymmetrization of Primary Alcohols: Synthesis of Enantiocomplementary Chiral β-Nitroalcohols
Chatterjee, Ayon,Kumar Padhi, Santosh,Rao, D. H. Sreenivasa
supporting information, p. 5310 - 5318 (2021/10/02)
Biocatalytic asymmetrization of inexpensive and stable primary alcohols to prepare enantioenriched β-nitroalcohols is an important development in green chemistry for the production of chiral pharmaceutical intermediates. Herein, we report a one-pot, two-step cascade reaction sequence in which first benzylic alcohols were oxidized to produce corresponding benzaldehydes using horse liver alcohol dehydrogenase (HLADH). The in situ generated aldehydes were then reacted in a biphasic medium with nitromethane by Arabidopsis thaliana hydroxynitrile lyase (AtHNL) or Baliospermum montanum HNL (BmHNL) catalyzed Henry reaction to produce stereoselective β-nitroalcohols with (R) or (S) configuration, respectively. Using HLADH-AtHNL, (R)-β-nitroalcohols were obtained in up to 64% conversion, and HLADH-BmHNL, (S)-β-nitroalcohols in up to 70% conversion, while in both cases excellent stereoselectivity (up to >99% ee) was achieved. The concept was proven by functionalization of sp3 C?H bond of ten simple achiral benzylic alcohols to enantiocomplementary chiral β-nitroalcohols. (Figure presented.).
Ketoreductase catalyzed stereoselective bioreduction of α-nitro ketones
Wang, Zexu,Wu, Xiaofan,Li, Zhining,Huang, Zedu,Chen, Fener
supporting information, p. 3575 - 3580 (2019/04/14)
We report here the stereoselective bioreduction of α-nitro ketones catalyzed by ketoreductases (KREDs) with publicly known sequences. YGL039w and RasADH/SyADH were able to reduce 23 class I substrates (1-aryl-2-nitro-1-ethanone (1)) and ten class II substrates (1-aryloxy-3-nitro-2-propanone (4)) to furnish both enantiomers of the corresponding β-nitro alcohols, with good-to-excellent conversions (up to >99%) and enantioselectivities (up to >99% ee) being achieved in most cases. To the best of our knowledge, KRED-mediated reduction of class II α-nitro ketones (1-aryloxy-3-nitro-2-propanone (4)) is unprecedented. Select β-nitro alcohols, including the synthetic intermediates of bioactive molecules (R)-tembamide, (S)-tembamide, (S)-moprolol, (S)-toliprolol and (S)-propanolol, were stereoselectively synthesized in preparative scale with 42% to 90% isolated yields, showcasing the practical potential of our developed system in organic synthesis. Finally, the advantage of using KREDs with known sequence was demonstrated by whole-cell catalysis, in which β-nitro alcohol (R)-2k, the key synthetic intermediate of hypoglycemic natural product (R)-tembamide, was produced in a space-time yield of 178 g L?1 d?1 as well as 95% ee by employing the whole cells of a recombinant E. coli strain coexpressing RasADH and glucose dehydrogenase as the biocatalyst.
