Method for producing diaminobenzene compound

A kind of technology of diaminobenzene and compound is applied in the field of diaminobenzene compound to achieve the effects of improving yield, promoting dissolution and increasing solubility

Inactive Publication Date: 2019-12-27
TOKUYAMA CORP
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AI-Extracted Technical Summary

Problems solved by technology

In the existing technology, ther...
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Method used

In the present invention, by making not only the alkali metal salt of the dithionous acid exist in the reaction system, but also the alkali metal carbonate, sometimes the reaction can be smoothly carried out in a short period of time, and at the same time, the side effects can be suppressed. reaction. Specifically, it is considered that side reactions such as sulfonation of the benzene ring can be suppressed by the presence of the alkali metal carbonate. In addition, it is considered that the alkali metal hydrogensulfate or alkali metal hydrogensulfite generated during the reaction can be neutralized to promote the reaction. Furthermore, since it is an inorganic salt, it is easy to remove after compl...
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Abstract

The purpose of the present invention is to provide a method for easily producing a diaminobenzene compound and a benzimidazole compound at low cost. The present invention provides a method for producing a diaminobenzene compound or N-protected aminobenzene compound represented by formula (2), the method comprising bringing an aminonitrobenzene compound or N-protected nitrobenzene compound represented by formula (1) into contact with an alkali metal salt of dithionous acid. Also provided is said method in which a deprotection reaction is conducted according to need. (In formulae (1) and (2), nis an integer of 1-4; R1 is a C1-6 alkyl, C1-6 alkoxy, C2-6 acyloxy, C2-6 alkoxycarbonyl, or nitro group or a halogen atom, and when n>=2, then the R1 moieties may be the same or different; and RA isa hydrogen atom or a protective group.)

Application Domain

Technology Topic

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  • Method for producing diaminobenzene compound
  • Method for producing diaminobenzene compound
  • Method for producing diaminobenzene compound

Examples

  • Experimental program(8)

Example Embodiment

[0183] Example 1 (Example of manufacturing diaminobenzene compound using aminonitrobenzene compound)
[0184] Carry out the following reaction.
[0185]
[0186] In a mixed solvent (reaction solvent) of dimethylformamide (DMF) (4ml), water (0.367ml, 20.4mmol) and toluene (3ml), methyl 2-amino-3-nitrobenzoate (1.0 g, 5.1mmol; 2-amino-3-nitrobenzene compound), sodium dithionite (purity 80% by mass) (3.33g, 15.3mmol ((the number of moles of sodium dithionite calculated from the purity)); Wako Pure Chemical Produced by the company, dithionite alkali metal salt), potassium carbonate (1.4g, 10.2 mmol; alkali metal carbonate) were stirred and mixed for 4 hours at a reaction temperature of 100°C (reaction time).
[0187] Water (14 mL) was added to the obtained reaction liquid, and then, the mixed liquid of the obtained reaction liquid and water was extracted with ethyl acetate (5 mL). The extraction based on this ethyl acetate (5 ml) was repeated 5 times. After washing the ethyl acetate solution (25ml in total) with water, it was concentrated under reduced pressure to obtain the target product methyl 2,3-diaminobenzoate (0.72g, 2,3-diaminobenzene compound; the product determined by the mass Rate: 85%, the conversion rate of the aminonitrobenzene compound determined by high performance liquid chromatography (HPLC) is 100%). In addition, the purity of methyl 2,3-diaminobenzoate confirmed by HPLC was 94.0%, and the polar impurity (presumably a compound having a sulfo group at position 5 (2,3-diamino-5-sulfobenzene) Methyl formate)) is 2.2%. The analysis value of methyl 2,3-diaminobenzoate is as follows.
[0188] IR(KBr)1693cm -1.
[0189] 1H-NMR (CDCl3) δ 7.30-7.80 (m, 1H), 6.40-7.10 (m.2H), 1.45 (brs, 2H), 3.85 (s, 3H), 3.40 (brs, 2H).

Example Embodiment

[0190] Example 2 (Example of manufacturing diaminobenzene compound using aminonitrobenzene compound)
[0191] Compared with Example 1, except for using sodium dithionite (purity 80% by mass) (2.22g, 10.2mmol ((the number of moles of sodium dithionite calculated from the purity)); Wako Pure Chemical Industries, the alkali of dithionite Metal salt), except for the reaction time of 5 hours, the same operation as in Example 1 was performed. The conversion rate was 10%. No polar impurities were confirmed.

Example Embodiment

[0192] Example 3 (Example of manufacturing diaminobenzene compound using aminonitrobenzene compound)
[0193] With respect to Example 1, except that the reaction solvent was a mixed solvent of DMF (7 ml) and water (0.099 ml, 5.1 mmol), the same operation as in Example 1 was performed. The yield of methyl 2,3-diaminobenzoate was 94%. The conversion rate is 100%. In addition, the purity of methyl 2,3-diaminobenzoate confirmed by HPLC was 95.4%, and the polar impurity was 2.5%. The analysis result of the obtained methyl 2,3-diaminobenzoate was the same as in Example 1.
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