Medicine Raw Materials Paracetamol API 103-90-2 Used As Antipyretic Analgesics

This product is used as antipyretic analgesics. It has the antipyretic activity by means of mediated peripheral vasodilation and perspiration caused by inhibiting the cyclooxygenase which selectively inhibiting the synthesis of hypothalamic thermoregulation prostaglandins, and its strength of antipyretic effect is similar to aspirin. As a peripheral analgesic, it can produce analgesic effect by inhibiting the synthesis and release of prostaglandins and increasing pain threshold. However, its action is weaker than aspirin and it is only effective for mild to moderate pain. There is no obvious anti-inflammation effect.

Production Produced by acetylation of p-aminophenol. Method 1: add p-aminophenol into dilute acetic acid, then add glacial acetic acid, heat up to 150℃and react for 7h, add acetic anhydride and react for 2h, check the end point and cool to 25℃ after the acceptance, shake it and filter, water until no acetic acid flavor exists, dry to get crude products. Method 2: distill p-aminophenol, acetic acid and acid industrial containing more than 50% acid together, the speed of distilling dilute acid for is 1/10 of the total distillate in one hour, check the residue of p-aminophenol less than 2.5% aminophenol by sampling inspection when inner temperature rises up to 130℃, add dilute acid (content of more than 50%), cool to get crystallization. After shaking and filter, first use a small amount of dilute acid to wash, and then use a large number of water till filtrate is near colourless to get crude products. The yield of method 1 is 90%, but the yield of method 2 is 90-95%. Refining methods: add the crude product when the water is heated to near boiling. Heat up to the total dissolution, add activated carbon soaked in water, use dilute acetic acid to adjust till pH=4.2-4.6, boil for 10min. Filter press, add a small amount of sodium bisulfite into the filtrate. Cool to below 20℃, separate crystals out. After shaking and filter, wash and dry to get active ingredients, paracetamol finished products. Other methods of production are as followed: (1) p-nitrophenol is reduced by zinc in acetic acid, and acetaminophen is obtained by acetylation at the same time; (2) put the hydrazone generated from p-hydroxyacetophenone in acid solution containing sulfuric acid, and then add sodium nitrite to get acetaminophen by renversement.