Heterocyclic compounds are organic compounds containing at least one atom of carbon, and at least one element other than carbon, such as sulphur, oxygen or nitrogen within a ring structure. These structures may comprise either simple aromatic rings or non-aromatic rings. Some examples are pyridine (C5H5N), pyrimidine (C4H4N2) and dioxane (C4H8O2). Many heterocyclic compounds, including some amines, are carcinogenic. This book details the proposed mechanisms of Gewald-like reactions and the wide scope of substituted 2-aminothiophenes for real life applications. Literary information about synthesis methods, structure, physical-chemical and biological properties is summarised, and also information about conversion of adamantyl-1 and adamantyl-2 imidazole and benzimidazole derivatives is given. In addition, 3-acetylindole derivatives have been in the centre of attention of researchers over many years due to the high practical value of these compounds. This book presents a survey of the literature on 3-acetylindoles chemistry and provides useful and up-to-date data for medicinal chemists.