A kind of method for preparing benzimidazolone

Abstract

The invention relates to a novel preparation method of benzimidazolone. The novel preparation method comprises the step of reacting o-phenylenediamine and dimethyl carbonate under the boiling point of an organic solvent in the existence of a catalyst to prepare benzimidazolone, wherein methanol serving as a byproduct can be recycled through simple condensation. According to the novel preparation method, dimethyl carbonate is used as a cyclizing agent, so that the produced byproduct is easily absorbed and utilized, and no wastewater is generated; reaction materials react in a homogeneous reaction system, and the reaction materials are sufficiently mixed; the reaction temperature is constant, the pH value is not needed to be regulated, and the reaction is easily controlled; and a solvent is applied for many times, so that green synthesis is realized, the yield of benzimidazolone is up to 98.5%, and the purity of benzimidazolone is up to 99.0%.

Description

technical field

[0001] The invention belongs to the field of preparation of chemical intermediates, and in particular relates to a new method for preparing benzimidazolone. Background technique

[0002] Benzimidazolone is an important organic intermediate, especially used in the fields of medicine, pigment and pesticide.

[0003] In the literature disclosed in J.Am.Chem.Soc.80, 1657 (1958), a method for preparing benzimidazolone by reacting o-phenylenediamine and phosgene is provided. However, the phosgene used in this method is highly dangerous, and the by-product hydrogen chloride generated by the reaction is highly corrosive to equipment.

[0004] Proposed by the patents US-4269989 and CN-9411729.9, o-phenylenediamine and urea are reacted in water, the temperature is controlled at 90°C to 120°C, and the pH is adjusted and controlled at 4 to 9 by acid to prepare benzimidazolone. stable, resulting in unstable yield, and a large amount of waste water causes environmental p...

Examples

Embodiment 1

[0031] In a 1000ml three-necked flask equipped with electric stirring, reflux condenser and thermometer, add 94.6g dimethyl carbonate, 108g o-phenylenediamine, 324g chlorobenzene and 0.108g phase transfer catalyst TEBA, heat up to solids are all dissolved, start stirring Continue to raise the temperature to 130°C, and keep the reaction system at 130°C for 4 hours. After completion of the reaction, cool down to room temperature, filter, wash with chlorobenzene, and dry to obtain 132 g of off-white product with a yield of 98.5% and a purity of 99.5%.

[0032] See the table below for the impact of mother liquor application on product yield and purity:

[0033] Apply times

[0034] As can be seen from the above table, the application of mother liquor has little impact on the purity and yield of the product. The solvent can be directly applied multiple times.

Embodiment 2

[0036] In a 1000ml three-necked flask equipped with an electric stirrer, a reflux condenser and a thermometer, add 94.6g dimethyl carbonate, 108g o-phenylenediamine, 1080g toluene and 0.108g phase transfer catalyst TEBA, heat up until all the solids are dissolved, start stirring and continue The temperature was raised to 110°C, and the reaction system was kept at 110°C for 8 hours. After completion of the reaction, cool down to room temperature, filter, wash with toluene, and dry to obtain 142 g of off-white product with a yield of 98.7% and a purity of 99.0%.

Embodiment 3

[0038] In a 1000ml three-necked flask equipped with electric stirring, reflux condenser and thermometer, add 94.6g dimethyl carbonate, 108g o-phenylenediamine, 324gDMSO and 0.324g phase transfer catalyst TEBA, heat up until the solids are completely dissolved, start stirring and continue to heat up To 150°C, the reaction system was kept at 150°C for 4 hours. After completion of the reaction, cool down to room temperature, filter, wash with DMSO, and dry to obtain 132 g of off-white product with a yield of 98.6% and a purity of 99.8%.

technical field

[0001] The invention belongs to the field of preparation of chemical intermediates, and in particular relates to a new method for preparing benzimidazolone. Background technique

[0002] Benzimidazolone is an important organic intermediate, especially used in the fields of medicine, pigment and pesticide.

[0003] In the literature disclosed in J.Am.Chem.Soc.80, 1657 (1958), a method for preparing benzimidazolone by reacting o-phenylenediamine and phosgene is provided. However, the phosgene used in this method is highly dangerous, and the by-product hydrogen chloride generated by the reaction is highly corrosive to equipment.

[0004] Proposed by the patents US-4269989 and CN-9411729.9, o-phenylenediamine and urea are reacted in water, the temperature is controlled at 90°C to 120°C, and the pH is adjusted and controlled at 4 to 9 by acid to prepare benzimidazolone. stable, resulting in unstable yield, and a large amount of waste water causes environmental p...

Examples

Embodiment 1

[0031] In a 1000ml three-necked flask equipped with electric stirring, reflux condenser and thermometer, add 94.6g dimethyl carbonate, 108g o-phenylenediamine, 324g chlorobenzene and 0.108g phase transfer catalyst TEBA, heat up to solids are all dissolved, start stirring Continue to raise the temperature to 130°C, and keep the reaction system at 130°C for 4 hours. After completion of the reaction, cool down to room temperature, filter, wash with chlorobenzene, and dry to obtain 132 g of off-white product with a yield of 98.5% and a purity of 99.5%.

[0032] See the table below for the impact of mother liquor application on product yield and purity:

[0033] Apply times

[0034] As can be seen from the above table, the application of mother liquor has little impact on the purity and yield of the product. The solvent can be directly applied multiple times.

Embodiment 2

[0036] In a 1000ml three-necked flask equipped with an electric stirrer, a reflux condenser and a thermometer, add 94.6g dimethyl carbonate, 108g o-phenylenediamine, 1080g toluene and 0.108g phase transfer catalyst TEBA, heat up until all the solids are dissolved, start stirring and continue The temperature was raised to 110°C, and the reaction system was kept at 110°C for 8 hours. After completion of the reaction, cool down to room temperature, filter, wash with toluene, and dry to obtain 142 g of off-white product with a yield of 98.7% and a purity of 99.0%.

Embodiment 3

[0038] In a 1000ml three-necked flask equipped with electric stirring, reflux condenser and thermometer, add 94.6g dimethyl carbonate, 108g o-phenylenediamine, 324gDMSO and 0.324g phase transfer catalyst TEBA, heat up until the solids are completely dissolved, start stirring and continue to heat up To 150°C, the reaction system was kept at 150°C for 4 hours. After completion of the reaction, cool down to room temperature, filter, wash with DMSO, and dry to obtain 132 g of off-white product with a yield of 98.6% and a purity of 99.8%.

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