Method for producing diaminobenzene compound

[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).

[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.

[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.