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  Bioactive Heterocyclic Compound Classes: Agrochemicals - Google Books

  https://books.google.de/books?id=PS3KUELD01sC&pg=PA214#v=onepage

  The chemistry of heterocycles is an important branch of organic chemistry. This is due to the fact that a large number of natural products, e. g. hormones, antibiotics, vitamins, etc. are composed of heterocyclic structures. Often, these compounds show…

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  Bioactive Heterocyclic Compound Classes: Pharmaceuticals - Google Books

  https://books.google.de/books?id=zk0cIhG4lIwC&pg=PA59#v=onepage

  The chemistry of heterocycles is an important branch of organic chemistry. This is due to the fact that a large number of natural products, e. g. hormones, antibiotics, vitamins, etc. are composed of heterocyclic structures. Often, these compounds show…

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