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Method for synthesizing naphthazarin and derivatives thereof

A synthesis method and technology of derivatives, applied in the field of medicine and chemical industry, can solve the problems of low reaction yield, harsh reaction conditions, severe reaction conditions, etc., and achieve the effects of high reaction yield, easy availability of raw materials and mild reaction conditions

Inactive Publication Date: 2011-04-13
SHANGHAI JIAO TONG UNIV
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Problems solved by technology

[0003] There are some reports on the synthesis of naphthalene and its derivatives. For example, 1,5-dinitronaphthalene is used as a raw material to react with oleum and sublimed sulfur in concentrated sulfuric acid to prepare naphthalene. The reaction conditions are severe and the product is difficult to purify. , the bibliographical report purifies with sublimation method, and yield is only 15% (under molten state, the effect of 1,4-dihydroxynaphthalene of different substituents on keto-enol interconversion [J].Organic Chemistry, 1978,43( 24), 4617-4621)
The most commonly used method is to prepare naphthalene by using p-hydroquinone as a raw material and dichloromaleic anhydride through condensation reaction, and then removing chlorine atoms through reduction. Stability (Electron Spectra of Differently Substituted Naphthoquinones, Tetrahedron, .1968, 24, 6053-6073)
Using 1,4-dimethoxybenzene instead of p-hydroquinone to condense with dichloromaleic anhydride can increase the reaction yield, and the yield in one step of condensation is 33%, but the subsequent demethylation becomes a key step affecting the yield
Such as oxidative demethylation with Lewis acid aluminum trichloride or boron tribromide, the yield is low, post-processing trouble, or the yield of demethylation with silver oxide and nitric acid is only 27% (racemate comfrey Synthesis of ketones and related compounds, Bulletin of the Chemical Society of Japan, 1987, 205-213.)
Electrooxidative demethylation of 1,4,5,8-tetramethoxynaphthalene derivatives, although the yield has increased, it is difficult to prepare naphthalene and its derivatives on a large scale
Due to the limitations of existing synthetic methods, it is difficult to obtain naphthalene, so the price is expensive

Method used

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  • Method for synthesizing naphthazarin and derivatives thereof
  • Method for synthesizing naphthazarin and derivatives thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0014] Embodiment 1,5,8-dimethoxy-1, the preparation of 4-naphthoquinone

[0015] Dissolve 1,4,5,8-tetramethoxynaphthalene (4.96g, 0.02mol) in acetonitrile (50ml), add dropwise excess ammonium cerium nitrate (32.9g, 0.06mol), and stir at room temperature for half an hour. Add Ethyl acetate (40ml) diluted the reaction solution, concentrated under reduced pressure to remove acetonitrile and ethyl acetate, then added 80ml of ethyl acetate, filtered, concentrated, and finally recrystallized with ether to obtain orange-yellow 5,8-dimethoxy- 1,4-naphthoquinone 4.27g, yield 98%. m.p.156-157℃. 1 HNMR (CDCl 3 , 300MHz): δ7.32(s, 2H, ArH×2), 6.77(s, 2H, H quinone ×2), 3.95(s, 6H, OCH 3 ×2), ESI-MS: 241.40 (M+Na) + .

Embodiment 2

[0016] Embodiment 2: Preparation of 1,4-diacetoxy-5,8-dimethoxynaphthalene

[0017] Dissolve 5,8-dimethoxy-1,4-naphthoquinone in acetic anhydride (12.5ml), then add triethylamine (2.5ml), N,N-lutidine (60mg, 0.5mmol) After stirring at room temperature for 1 hour, hydrochloric acid-activated zinc powder (16.25 g, 0.25 mol) was added in batches, and stirring was continued overnight. The reaction solution was poured into water, extracted with ethyl acetate, and the organic layer was washed with sodium bicarbonate, water, and saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain a crude product, which was recrystallized from ether to obtain 6.92 g of a light yellow solid. The rate is 91%.

[0018] m.p.127-128℃. 1 H NMR (CDCl 3 , 300MHz): δ7.05(s, 2H, ArH×2), 6.79(s, 2H, ArH×2), 3.87(s, 6H, OCH 3 ×2), 2.46(s, 6H, COCH 3 ×2). 13 C NMR (CDCl 3 , 75MHz): δ183.4, 169.4, 147.8, 138.7, 131.2, 124.5, 76.8, 21.2.ESI-MS: 327.28 (M+Na)...

Embodiment 3

[0019] Example 3: Preparation of 5,8-diacetoxy-1,4-naphthoquinone

[0020] 1,4-diacetoxy-5,8-dimethoxynaphthalene (5.48g, 0.02mol) was dissolved in acetonitrile (50ml), and the method was the same as in Example 1 to obtain dark yellow 5,8-diacetoxy 5.43 g of 1,4-naphthoquinone was obtained, and the yield was 99%. m.p.190-191℃. 1 HNMR (CDCl 3 , 300MHz): δ7.39(s, 2H, ArH×2), 6.80(s, 2H, H quinone ×2), 2.46(s, 6H, COCH 3 ×2).ESI-MS: 297.22 (M+Na) + .

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Abstract

The invention discloses a method for synthesizing naphthazarin and derivatives thereof, and belongs to the technical field of medical chemical industry. 1,4,5,8-tetramethoxyl naphthalene or derivatives thereof are taken as raw materials, and the method comprises the following steps of: oxidating and demethylating by using cerium ammonirm nitrate to obtain 5,8-dimethoxy-1,4-naphthoquinone or derivatives thereof; acetylizing to obtain 2-methyl-1,4-naphthoquinol or derivatives thereof; oxidating and demethylating by using cerium ammonirm nitrate to obtain 5,8-acetoxy-1,4-naphthoquinone or derivatives thereof; and hydrolyzing to obtain the naphthazarin or derivatives thereof. In the method, the raw materials are readily available, reaction conditions are mild, the yield of reaction in each step is high, and the method is suitable for industrial production.

Description

technical field [0001] The invention relates to a method in the technical field of medicine and chemical engineering, in particular to a method for synthesizing naphthalene and its derivatives. Background technique [0002] Naphthalene (5,8-dihydroxynaphthoquinone) is a natural compound with various biological activities, such as antibacterial, antifungal, antiparasitic, inducing apoptosis, etc. Naphthalene is also an important intermediate for the synthesis of dyes Many quinone natural products contain naphthalene mother rings such as shikonin, arcanin, etc. (Chemical and biological characteristics of arcanin, shikonin and related naphthalene natural products, German Applied Chemistry, 1999, 38 , 270-300). [0003] There are some reports on the synthesis of naphthalene and its derivatives. For example, 1,5-dinitronaphthalene is used as a raw material to react with oleum and sublimed sulfur in concentrated sulfuric acid to prepare naphthalene. The reaction conditions are se...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C50/32C07C46/00
Inventor 李绍顺周文郑小刚彭瑛
Owner SHANGHAI JIAO TONG UNIV