621-23-8Relevant articles and documents
Bryant
, p. 1345 (1967)
Efficient 1H nuclear magnetic resonance method for improved quality control analyses of Ginkgo constituents
Li, Chia-Ying,Lin, Chun-Hua,Wu, Chia-Che,Lee, Kuo-Hsiung,Wu, Tian-Shung
, p. 3721 - 3725 (2004)
We developed an analytical method using 1H nuclear magnetic resonance (NMR) spectrometry to resolve analytical problems with Ginkgo. After a simple hydrolysis step, an NMR analysis of the terpene trilactone H-12 signals and the flavonol aglycone H-2′ (or H-2′/6′ for kaempferol) signals was performed. By comparing the solvent effects on the resolution of these signals, methanol-d4-benzene-d6 (65:35) was selected as the optimal 1H NMR solvent. The amounts of terpene lactones and flavonol aglycones in various commercial Ginkgo products and Ginkgo leaves were determined. This newly developed 1H NMR method enables the simultaneous analysis of terpene trilactones and flavonols and allows simple, rapid quantification of these compounds in pharmaceutical Ginkgo preparations.
Preparation method of trimethylphloroglucinol
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Paragraph 0029-0043, (2021/09/21)
The invention discloses a preparation method of trimethylphloroglucinol. According to the invention, phloroglucinol is taken as a raw material, and sulfuric acid is adopted to catalyze a first-step reaction, so operation is simpler and more convenient, reaction byproducts are reduced, and damage to production equipment is reduced; and a reaction product obtained in the first-step reaction and dimethyl carbonate are subjected to a second-step methylation reaction, and dimethyl carbonate is non-toxic and non-corrosive, so production safety is greatly improved, the method is green and environment-friendly, and the quality and yield of a final finished product are improved. The method solves the problem of low safety in the production process of existing trimethylphloroglucinol preparation methods, avoids the use of strong corrosive reagents such as hydrochloric acid, and adopts dimethyl carbonate to replace a highly toxic reagent, namely dimethyl sulfate.
Catalytic SNAr Hydroxylation and Alkoxylation of Aryl Fluorides
Kang, Qi-Kai,Li, Ke,Li, Yuntong,Lin, Yunzhi,Shi, Hang,Xu, Lun
supporting information, p. 20391 - 20399 (2021/08/13)
Nucleophilic aromatic substitution (SNAr) is a powerful strategy for incorporating a heteroatom into an aromatic ring by displacement of a leaving group with a nucleophile, but this method is limited to electron-deficient arenes. We have now established a reliable method for accessing phenols and phenyl alkyl ethers via catalytic SNAr reactions. The method is applicable to a broad array of electron-rich and neutral aryl fluorides, which are inert under classical SNAr conditions. Although the mechanism of SNAr reactions involving metal arene complexes is hypothesized to involve a stepwise pathway (addition followed by elimination), experimental data that support this hypothesis is still under exploration. Mechanistic studies and DFT calculations suggest either a stepwise or stepwise-like energy profile. Notably, we isolated a rhodium η5-cyclohexadienyl complex intermediate with an sp3-hybridized carbon bearing both a nucleophile and a leaving group.
Synthesis method of high-purity phloroglucinol compound
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Paragraph 0018, (2021/06/09)
The invention discloses a one-step chemical catalytic synthesis method of high-purity phloroglucinol by taking 3,5-dichlorophenol as a starting material and taking strong base and a catalyst as auxiliary materials. Through the method, the phloroglucinol compound with high molar yield, high purity and low cost can be effectively synthesized.