The preparation method of 3-aminosalicylic acid
A technology of aminosalicylic acid and salicylic acid, applied in the field of chemical industry, can solve the problems of no industrialized product, difficult to purify, high price of 3-nitrosalicylic acid and the like
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
Method used
Image
Examples
Embodiment 1
[0025] Preparation of 5-chloro-3-nitrosalicylic acid
[0026] Add 20 grams of 5-chlorosalicylic acid and 100 milliliters of glacial acetic acid into the reaction flask, and stir under ice until the glacial acetic acid begins to solidify. Mix 8.9 grams of 90% fuming nitric acid with 6 milliliters of glacial acetic acid, add it to a constant pressure dropping funnel, remove the ice bath, and slowly drop it into the reaction flask under a water bath at room temperature. After the dropwise addition was completed in about 20 minutes, stirring was continued for 150 minutes in a water bath at room temperature. After the reaction was complete, the system was poured into 120 ml of crushed ice and stirred for 30 minutes. Filter, wash, and dry the filter cake overnight at 40°C. The crude product was recrystallized from ethanol-water to obtain 15.8 g of bright yellow solid. m.p: 162-166°C; MS (ESI - ) 216[M-H] - ; 1 H-NMR (400MHz, DMSO-d 6 ): δ8.21 (1H, d, J=2.4Hz), 8.02 (1H, d, J=...
Embodiment 2
[0030] Preparation of 5-bromo-3-nitrosalicylic acid
[0031] Add 20 grams of 5-bromosalicylic acid and 100 milliliters of glacial acetic acid into the reaction flask, and stir under ice until the glacial acetic acid begins to solidify. Mix 7.8 grams of 90% fuming nitric acid with 6 milliliters of glacial acetic acid, add it to a constant pressure dropping funnel, remove the ice bath, and slowly drop it into the reaction flask under a water bath at room temperature. After the dropwise addition was completed in about 20 minutes, stirring was continued for 150 minutes in a water bath at room temperature. After the reaction was complete, the system was poured into 120 ml of crushed ice and stirred for 30 minutes. Filter, wash, and dry the filter cake overnight at 50°C. The crude product was recrystallized from ethanol-water to obtain 15.4 g of a bright yellow solid, with a yield of 64.3%. MS (ESI) 261 [M-H] - ; 1 H-NMR (400MHz, DMSO-d 6 ): δ8.29(d, J=2.4Hz, 1H), 8.12(d, J=2....
Embodiment 3
[0035] Preparation of 5-chloro-3-nitrosalicylic acid
[0036] Repeat the preparation of 5-chloro-3-nitrosalicylic acid in Example 1
[0037] Preparation of 3-aminosalicylic acid
[0038] In a reaction flask, 10 g of 5-chloro-3-nitrosalicylic acid, 5 g of ammonium formate, 25 ml of water, 25 ml of methanol, and 1 g of palladium catalyst deposited on activated carbon at 10% by weight were added. The reaction was stirred at 35° C., and after 5 hours of reaction, the reaction was complete as monitored by LC-MS. The reaction solution was filtered, and the filtrate was spin-dried under reduced pressure. Dissolve the solid in 25 ml of water, filter, and remove the insoluble matter to obtain a yellow liquid. Adjust the pH of the solution to 4 with ammonia water in an ice bath, and a large amount of solid precipitates. Cool sufficiently, filter with suction, wash with water, and filter the cake at room temperature. After drying under reduced pressure, 4.5 g of off-white solid was ob...
PUM
Login to View More Abstract
Description
Claims
Application Information
Login to View More