99395-88-7Relevant articles and documents
Catalytic enantioselective synthesis of β-amino alcohols by nitrene insertion
Zhou, Zijun,Tan, Yuqi,Shen, Xiang,Ivlev, Sergei,Meggers, Eric
, p. 452 - 458 (2020/12/31)
Chiral β-amino alcohols are important building blocks for the synthesis of drugs, natural products, chiral auxiliaries, chiral ligands and chiral organocatalysts. The catalytic asymmetric β-amination of alcohols offers a direct strategy to access this class of molecules. Herein, we report a general intramolecular C(sp3)-H nitrene insertion method for the synthesis of chiral oxazolidin-2-ones as precursors of chiral β-amino alcohols. Specifically, the ring-closing C(sp3)-H amination of N-benzoyloxycarbamates with 2 mol% of a chiral ruthenium catalyst provides cyclic carbamates in up to 99% yield and with up to 99% ee. The method is applicable to benzylic, allylic, and propargylic C-H bonds and can even be applied to completely non-activated C (sp3)-H bonds, although with somewhat reduced yields and stereoselectivities. The obtained cyclic carbamates can subsequently be hydrolyzed to obtain chiral β-amino alcohols. The method is very practical as the catalyst can be easily synthesized on a gram scale and can be recycled after the reaction for further use. The synthetic value of the new method is demonstrated with the asymmetric synthesis of a chiral oxazolidin-2-one as intermediate for the synthesis of the natural product aurantioclavine and chiral β-amino alcohols that are intermediates for the synthesis of chiral amino acids, indane-derived chiral Box-ligands, and the natural products dihydrohamacanthin A and dragmacidin A.[Figure not available: see fulltext.].
Preparation method of S-4-phenyl-2-oxazolidinone
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Paragraph 0021-0022, (2021/05/01)
The invention discloses a preparation method of S-4-phenyl-2-azolidinone. The preparation method comprises the following steps: reducing a compound 8 by potassium borohydride under acidic conditions to obtain a compound 9, and cyclizing the compound 9 and diethyl carbonate under alkaline conditions to obtain a compound 10, thereby obtaining (s)-4-phenyl-2-azolidinone. The raw materials used in the preparation method are easy to obtain, the reaction conditions are mild, the steps are simple, flammable and explosive reagents are not used, and the preparation method is suitable for large-scale industrial production and high in safety; the reaction yield is higher, and the cost is lower. Wide application prospects are realized.
Preparation method of oxazolidinone compound
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Paragraph 0051; 0056-0057, (2021/11/10)
The preparation method comprises the following steps 1): dissolving aromatic amino acid in methanol, dissolving the aromatic amino acid in methanol, heating up to 50 - 60 °C heat preservation 1 - 2h, 2) reducing: adding a catalytic amount of lithium salt in ethanol water as a solvent. 3) Ring-closing: toluene is used as a solvent, a reduction product and diethyl carbonate are added to 100 °C, a sodium methoxide solution is added dropwise, and the product is obtained after completion of the dropwise addition and after-treatment and purification after completion of the normal pressure distillation to the temperature of 100 °C heat preservation. The lithium salt is introduced to participate in the reaction, sodium borohydride is selected as a solvent, sodium borohydride is completely dissolved, and the lithium salt can be free from the compound to improve the reaction activity, so that the use amount of sodium borohydride is reduced to 2 equivalent, and the production cost is remarkably reduced.
