CoachA synthesis is the preparation of a chemical species by one or several chemical reactions, starting from other species. The solid or liquid recovered straight from the reaction mixture, before any purification, is the crude product: it still contains reactants, by-products and solvent.
Examples
Example 28.3 (Making aspirin)
Salicylic acid reacts with ethanoic anhydride (also called acetic anhydride) to give aspirin and ethanoic acid:
The anhydride is put in excess, so that all the salicylic acid reacts; the ethanoic acid formed is a by-product.