A kind of preparation method of 5-methylpyrazine-2-carboxylic acid
A technology of methylpyrazine and dimethylpyrazine, which is applied in the field of preparation of pharmaceutical intermediates, can solve the problems of complicated operation, low yield, low product conversion rate, etc., achieve non-reactive waste liquid discharge and reduce production cost , the effect of improving product quality
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
Method used
Image
Examples
Embodiment 1
[0037] In a 1L reaction flask equipped with a reflux condenser, add 500ml of water, 40g, 370mol of 2,5-dimethylpyrazine, 9.8g, 62mol of potassium permanganate, raise the temperature to 90°C, keep it at 90°C for 1h, and the solution After the purple color fades, cool down to 80°C, then add 9.8g, 62mmol of potassium permanganate, slowly raise the temperature to 90°C, keep it at 90°C for 1 hour, keep the solution for 1.5 hours after the purple color fades, and cool down to 20°C; Wash with 25ml of water and combine the filtrates; the combined filtrates are first concentrated at normal pressure, after 80% of the filtrate is evaporated, then distilled to dryness under reduced pressure; about 500g of the filtrate is evaporated, which contains 32g of 2,5-dimethylpyrazine ;
[0038] Add 30ml of water to the evaporated reaction bottle, raise the temperature to 48°C, and fully dissolve; use 1.2Kg of 1+1 sulfuric acid to adjust the pH of the solution to 2.5, extract 3 times with butanone ...
Embodiment 2
[0041] In a 100L reactor equipped with a reflux condenser, add 50kg of water, 60mol of 2,5-dimethylpyrazine, and 12mol of potassium permanganate, raise the temperature to 85°C, and keep it at 85°C for 1.2h. After the purple color of the solution fades, Cool down to 80°C, then add 12mol of potassium permanganate, slowly raise the temperature to 85°C, keep warm at 85°C for 1.2h, the purple color of the solution fades and keep warm for 2h, cool down to 25°C; press filter, wash the filter cake with 2.5 kg of water , after merging the filtrate, concentrate at normal pressure first, change the vacuum distillation to dryness after steaming 85% of the filtrate; steam the filtrate 50kg, which contains 2,5-dimethylpyrazine 5.3kg;
[0042] Add 3kg of water to the evaporated kettle, raise the temperature to 50°C, and fully dissolve; adjust the pH to 2.5 with about 1.2Kg of 1+1 sulfuric acid, extract 3 times with butanone (16Kg×3) at 50°C, and combine the organic phases; Let the organic ph...
Embodiment 3
[0044] In a 500L reaction kettle equipped with a reflux condenser, add 250kg of water, 20kg of 2,5-dimethylpyrazine, and 4.0kg of potassium permanganate, raise the temperature to 82°C, and keep it at 80°C for 1.6h. After the purple color of the solution fades Cool down to 76°C, then add 4.0kg of potassium permanganate, slowly raise the temperature to 82°C, keep warm at 82°C for 1.6h, the purple color of the solution fades and keep warm for 2.5h, cool down to 22°C; press filter, wash the filter residue with 12kg of water Cake, combined filtrate; the combined filtrate was first concentrated at normal pressure, distilled off water and pyrazine solution (recovered mechanically), and after about 82% was distilled off, it was distilled under reduced pressure to dryness; 250kg of filtrate was distilled out of which, containing 2,5- Dimethylpyrazine 17kg;
[0045] Add 15kg of water to the evaporated kettle, raise the temperature to 52°C, and fully dissolve; then pump it into the neutr...
PUM
Login to View More Abstract
Description
Claims
Application Information
Login to View More