775-15-5Relevant articles and documents
Enantioselective reduction of heterocyclic ketones with low level of asymmetry using carrots
Machado, Naira Vieira,Omori, álvaro Takeo
, p. 475 - 480 (2021/09/27)
A whole spectrum of biocatalysts for asymmetric reduction of prochiral ketones is well known including the Daucus carota root. However, this type of reaction is still challenging when pro-chiral ketones present low level of asymmetry, like heterocyclic ketones. In this work, 4,5-dihydro-3(2H)-thiophenone (1), 2-methyltetrahydrofuran-3-one (2), N-Boc-3-pyrrolidinone (3), 1-Z-3-pyrrolidinone (4) and 1-benzyl-3-pyrrolidinone (5) were studied in order to obtain the respective enantioselective heterocyclic secondary alcohols. Except for 5, the corresponding alcohols were obtained in high values of conversion and with high selectivity. In order to circumvent the low isolated yield of the corresponding chiral alcohol from 2, we observed that the use of carrots in the absence of water is feasible. Addition of co-solvents was needed to the water-insoluble ketones 3 and 4. Comparatively, baker’s yeast was used for bio reductions of 1, 3 and 4. And in terms of conversion, selectivity and work-up, the use of carrots were a more efficient biocatalyst, as well as a viable method for obtaining 5-member heterocyclic secondary alcohols.
Stereo-complementary bioreduction of saturated N-heterocyclic ketones
Li, Chao,Liu, Yan,Pei, Xiao-Qiong,Wu, Zhong-Liu
, p. 90 - 97 (2017/04/28)
The asymmetric bioreduction of several saturated N-heterocyclic ketones is demonstrated in a stereo-complementary fashion using the ketoreductases READH and ChKRED20 for the production of (S)- and (R)-alcohols, respectively. The reaction accepts substrates with a five-, six- or seven-membered ring, and exhibits excellent stereoselectivity when using 2-propanol as both the ultimate reducing agent and cosolvent, achieve >99% ee in the majority of cases for both enantiomers.
Preparation method of N-substituent-3-hydroxytetrahydropyrrole
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Paragraph 0022; 0023; 0024; 0025; 0026; 0027, (2017/08/29)
The invention discloses a preparation method of N-substituent-3-hydroxytetrahydropyrrole. The preparation method takes 1,2,4-butanetriol as a starting material, and comprises the following steps: performing a halogenating reaction between the starting material and hydrogen halide to prepare an intermediate 1,4-dihalogeno-2-butanol first, and then performing a condensation reaction with primary amine RNH2 to obtain a target product, wherein R represents methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tertiary butyl or benzyl; the halogenating reaction is performed in the presence of an acidic catalyst, and the acidic catalyst is formic acid or acetic acid; and hydrogen halide is hydrogen chloride or hydrogen bromide. The preparation method disclosed by the invention is relatively short in synthetic route, the starting material 1,2,4-butanetriol is low in price and easy to obtain, and other materials used in the method are relatively high in safety and also relatively low in price, so that the preparation method is suitable for industrial large-scale production. Particularly, the halogenating reaction can obtain a yield of 50% or above by selection of suitable halogenating agents and catalysts.
