Unit 1 Production of Drugs Depending on their production or origin pharmaceutical agents can be split into three groups: I .Totally synthetic materials (synthetics)，Ⅱ.Natural products，and Ⅲ .Products from partial syntheses (semi-synthetic products). The emphasis of the present book is on the most important compounds of groups I and Ⅲ一thus Drug synthesis. This does not mean，however，that natural products or other agents are less important. They can serve as valuable lead structures，and they are frequently needed as starting materials or as intermediates for important synthetic products. Table 1 gives an overview of the different methods for obtaining pharmaceutical agents. 1 单元生产的药品 其生产或出身不同药剂可以分为三类：1。完全（合成纤维）合成材料，Ⅱ。天然产物，和 Ⅲ。产品从（半合成产品）的部分合成。 本书的重点是团体的最重要的化合物Ⅰ和Ⅲ一所以药物合成。这并不意味着，但是，天然产品或其他代理人并不太重要。它们可以作为有价值的领导结构，他们常常为原料，或作为重要的合成中间体产品的需要。 表 1 给出了获取药剂的不同方法的概述。 Table 1 Possibilities for the preparation of drugs Methods Examples 1. Total synthesis -over 75 % of all pharmaceutical agents (synthetics) 2. Isolation from natural sources (natural products): 2.Plants -alkaloids;enzymes;heart glycosides;polysaccharides;tocopherol; steroid precursors (diosgenin, sitosterin);citral (intermediate product for vitamins A, E，and K) 2.2 Animal organs 一enzymes;peptide hormones;cholic acid from gall; insulin) from the pancreas;sera and vaccines 2. 3 Other sources 一cholesterol from wool oils;L-amino acids from keratin and gelatine hydrolysates 3. Fermentation 一antibiotics;L-amino acids;dextran; targeted modifications on steroids， e.g. 11-hydroxylation; also insulin, interferon, antibodies, peptide hormones，enzymes，va...
