阿司匹林Aspirin

分子含苯环、羧基和乙酰氧基（酯基）。阿司匹林把乙酰基转移到环氧合酶（COX-1、COX-2）活性中心附近的丝氨酸残基上，不可逆地使酶失活，从而阻断前列腺素和血栓素的生成。这一机理由英国药理学家韦恩在 1971 年阐明，他因此分享了 1982 年诺贝尔生理学或医学奖。

The molecule has a benzene ring, a carboxylic acid and an acetoxy (ester) group. Aspirin transfers its acetyl group to a serine near the active site of cyclooxygenase (COX-1 and COX-2), irreversibly inactivating the enzyme and blocking the synthesis of prostaglandins and thromboxane. The British pharmacologist John Vane worked out this mechanism in 1971 and shared the 1982 Nobel Prize in Physiology or Medicine.

古埃及和希波克拉底时代已用柳树皮止痛退热。1828 年毕希纳从柳树皮中提取出水杨苷；1853 年热拉尔首次合成乙酰水杨酸，但未纯化。1897 年拜耳公司的霍夫曼制得稳定纯净的产品，1899 年以 Aspirin 为商品名上市，名字中的 a 指乙酰基，spir 来自含水杨酸的植物绣线菊属（Spiraea）。

Willow bark was used against pain and fever in ancient Egypt and by Hippocrates. Buchner extracted salicin from willow bark in 1828, and Gerhardt first made acetylsalicylic acid in 1853 without purifying it. In 1897 Felix Hoffmann at Bayer produced a pure, stable product, launched in 1899 as Aspirin: the a stands for acetyl and spir for Spiraea, a plant source of salicylic acid.

实验室和工业上都用水杨酸与乙酸酐在少量浓硫酸或磷酸催化下乙酰化，约 80–90 °C 反应。粗品用乙醇-水重结晶。产品中残留的水杨酸可用 FeCl₃ 检验：酚羟基与 Fe³⁺ 显紫色，纯阿司匹林不显色。

In the laboratory and in industry, salicylic acid is acetylated with acetic anhydride at about 80–90 °C, catalysed by a little concentrated sulfuric or phosphoric acid. The crude product is recrystallised from ethanol–water. Residual salicylic acid is detected with FeCl₃: the phenol gives a violet colour with Fe³⁺, while pure aspirin does not.

常用剂量 300–1000 mg 用于解热镇痛，75–100 mg/日用于抗血小板。主要不良反应是胃肠道刺激和出血。16 岁以下儿童病毒感染时服用可能引发瑞氏综合征，因此通常避免。阿司匹林在潮湿环境中会缓慢水解为水杨酸和乙酸，开瓶后有醋味说明已变质。

Doses of 300–1000 mg relieve pain and fever, and 75–100 mg a day is used as an antiplatelet agent. The main side effects are stomach irritation and bleeding. In children under 16 with viral infections it can trigger Reye's syndrome, so it is usually avoided. In moist air it slowly hydrolyses to salicylic and acetic acids; a vinegar smell means the tablets have degraded.