Efficient synthesis of substituted 2-aminopyrazines: FeCl3-promoted condensation of hydroxyiminoketones with aminoacetonitriles

Review on the Synthesis of Pyrazine and Its Derivatives

Pyrazine is a kind of natural product which can be found in plants, animals, insects, marine organisms andmicroorganisms. The main function of pyrazine in living organisms is used as flavor of the raw foods. Pyrazine and its derivatives were also produced in industries mainly for fragrance, flavor and pharmaceutical applications. This review describes the historical development of pyrazine including the discovery and synthesis, to the recent synthetic approach of pyrazinium. In general, six synthetic approaches namely condensation reaction, ring closure, metal catalysis, green reaction, Maillard reaction and acid catalyst on N-substitution have been reviewed in this paper. The first five approaches are mainly aimed for the substitution at 2, 3, 5 and 6 positions in pyrazine ring, whereas the last approach is specifically for 1 and 4 positions in pyrazine. Keywords: Diazine, pyrazine, and Maillard reaction

Luminescence of imidazo[1,2-a]pyrazin-3(7H)-one compounds

In this review I will discuss chemical principles of the luminescence of imidazo[1,2-a]pyrazin-3(7H)-one compounds described to date. The review is composed of two main parts, the first dealing with the bioluminescence of coelenterate luciferin "coelenterazine" and Cypridina luciferin in marine organisms and the second with the chemiluminescence of these luciferins and their analogues. In the second section, possible applications of chemiluminescence and enhanced chemiluminescence in the area of bioassay are also discussed.