de novo synthesis和total synthesis 有什么区别

de novo synthesis(从头合成) :应该是从简单的碳氢化合物开始合成 total synthesis （全合成）：应该是从廉价易得的原料开始把，或从较容易得到目标化合物的原料开始，所需反应步骤应简单 De novo synthesis refers to the synthesis of complex molecules from simple molecules such as sugars or amino acids, as opposed to their being recycled after partial degradation. For example, de novo synthesis of nucleotides is an alternative to the salvage pathway. In principle a total synthesis is the complete chemical synthesis of complex organic molecules from their constituent elements. In practice, simple, commercially available (often petrochemical) precursors or natural products (e.g. sugars) are used as starting materials and it is assumed that these have or can be synthesised from their constituent elements. Total syntheses are often used as a playground for the development of new chemical reactions and routes, and highlight the sophistication of modern synthetic organic chemistry.