Preparation process of 3,6-dihydroxy-2-naphthaldehyde

A dihydroxynaphthalene and dihydroxyl technology, applied in the field of organic synthesis, can solve problems such as long synthesis steps and unsatisfactory yield, and achieve the effects of shortening steps, reducing waiting time for reaction, and increasing yield

CN110218149AInactive Publication Date: 2019-09-10GUANGDONG UNIV OF TECH
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2019-09-10
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention belongs to the field of organic synthesis, and particularly relates to a preparation process of 3,6-dihydroxy-2-naphthaldehyde. The process includes a step 1) of subjecting 2,7-dihydroxynaphthalene to bromination with liquid bromine to form a first compound the structure of which is shown as a formula I; a step 2) of subjecting the first compound to a nucleophilic substitution reaction to generate the 3,6-dihydroxy-2-naphthaldehyde. The process solves a problem that preparation processes in the prior art have long synthesis steps and unsatisfactory yields.
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Description

technical field

[0001] The invention belongs to the field of organic synthesis, and in particular relates to a preparation method of 3,6-dihydroxy-2-naphthaldehyde. Background technique

[0002] 3,6-Dihydroxy-2-naphthaldehyde is an important intermediate of coumarin derivatives. Since its discovery in the early 19th century, coumarin has been widely used as a fluorescent dye for the development of molecular probes and imaging agents, in addition to its wide application in perfume, pharmaceuticals, and photosensitization. However, benzocoumarin absorbs and emits in a longer wavelength region, which is very beneficial for biological imaging applications, and has obvious two-photon absorption characteristics, that is, tissue imaging characteristics. In addition, coumarins with electron donor and acceptor groups at the 3-position and 8-position, respectively, are outstanding in terms of quantum yield, emission wavelength, and absorption wavelength. And existing 3, the syntheti...

Examples

Embodiment 1

[0025] Step 1: Add glacial acetic acid to 2,7-dihydroxynaphthalene. Add liquid bromine in glacial acetic acid solution with a constant pressure funnel at 10-15°C. After dripping, react at 60°C for one hour; then add an appropriate amount of water and tin powder, adjust the temperature to 80°C, and react overnight; carry out suction filtration the next day, wash the solid with water, and finally extract with ethyl acetate to obtain crude product; after drying the organic phase, the crude product is chromatographed using an eluent and through a thin-layer column to obtain the first compound.

[0026] Step 2: Add tetrahydrofuran to the first compound, dissolve it and remove oxygen, then lower the temperature at -76°C, add tert-butyllithium, and a solid is formed; after 40 minutes of reaction, raise the reaction temperature to room temperature for reaction One hour, then cool down at -76°C for 30 minutes; then add dry N,N-dimethylformamide, gradually warm up to room temperature, ...