On May 25, 2016, Chen, Congxi; Tian, Yongjian; Liang, Qiuyan; Bao, Xiaowei published a patent.COA of Formula: C8H8O4 The title of the patent was Preparation method of dracorhodin and its hydrochloride and perchlorate, intermediates. And the patent contained the following:
The title preparation method includes (1) performing Vilsmeier formylation reaction of 1,3,5-trimethoxybenzene (formula SM) and formylating agent (N,N-dimethylformamide or N-methyl-N-phenylformamide) to obtain 2,4,6-trimethoxybenzaldehyde (I); (2) performing Huangminglong reduction reaction with 50-85 wt% hydrazine hydrate and sodium hydroxide or potassium hydroxide in solvent B (ethylene glycol or glycerol monomethyl ether) to obtain 1,3,5-trimethoxy-2-methylbenzene (II); (3) performing Vilsmeier formylation reaction with the formylating agent to obtain 2,4,6-trimethoxy-3-methylbenzaldehyde (III); (4) cracking methoxy of the compound III with demethylation reagent (boron halide, aluminum halide, etc.) in solvent D (1,2-dichloroethane, dichloromethane, etc.) to obtain 2,4,6-trihydroxy-3-methylbenzaldehyde (IV); (5) performing substitution reaction with benzyl halide in solvent E (acetone, DMF, etc.) in presence of alkali E (potassium carbonate, sodium carbonate, etc.) to obtain 4,6-bis(benzyloxy)-2-hydroxy-3-methylbenzaldehyde (formula V); (6) performing substitution reaction with methylation agent (di-Me carbonate or iodomethane) in solvent F (acetone, DMF, etc.) to obtain 4,6-bis(benzyloxy)-2-methoxy-3-methylbenzaldehyde (VI); (7) performing benzyl protecting group removal reaction with hydrogen gas in solvent G (ethanol, methanol, etc.) in presence of noble metal catalyst (5-10 wt% palladium/carbon or palladium hydroxide/carbon) under protection of nitrogen gas to obtain 4,6-dihydroxy-2-methoxy-3-methylbenzaldehyde (VII); (8) performing condensation reaction with acetophenone in presence of acetic acid and hydrogen chloride to obtain dracorhodin hydrochloride (VIII); (9) dissolving in methanol, adding saturated sodium acetate solution, and crystallizing to obtain dracorhodin (X); or (10) reacting dracorhodin hydrochloride with perchloric acid to obtain dracorhodin perchlorate (IX). The preparation method has short process route, readily available raw materials, high product yield, low cost, good process reproducibility, and environment friendliness. The experimental process involved the reaction of 2,4,6-Trihydroxy-3-methylbenzaldehyde(cas: 55743-13-0).COA of Formula: C8H8O4
The Article related to dracorhodin perchlorate preparation, Heterocyclic Compounds (One Hetero Atom): Benzopyrans (Including Coumarins, Isocoumarins, Chromones, Benzopyrones, Dibenzopyrans, and Other Arenopyrans) and other aspects.COA of Formula: C8H8O4
Referemce:
Alcohol – Wikipedia,
Alcohols – Chemistry LibreTexts