This book provides a systematic and comprehensive treatment of the structures, syntheses, and reaction processes of heterocyclic compounds containing nitrogen, oxygen, and sulfur. Unsaturated heterocyclic systems ranging from three-membered to seven-membered rings are examined with emphasis on their physical and spectroscopic properties, natural occurrence, biological activities, and synthetic methodologies

The text begins with molecular physical and spectroscopic data, followed by discussions of the occurrence and biological activities of natural and synthetic heterocyclic compounds. Synthetic methods and reaction mechanisms are analyzed in detail, with particular attention given to fundamental reactions and structure–reactivity relationships. Compounds possessing the same ring framework but different heteroatoms are compared systematically, highlighting both their similarities and their structural and reactivity differences.

Following the discussion of synthesis and mechanisms, the reactions of the corresponding heterocyclic compounds are examined in a systematic manner. Monocyclic heterocycles fused with a benzene ring at different positions are also treated comparatively and systematically.

Heterocyclic compounds play a central role in modern chemistry, particularly in pharmaceutical research and materials science. Many biologically active molecules, therapeutic agents, and functional materials contain heterocyclic frameworks. This book is intended to provide students and researchers with a solid understanding of the synthesis, reactivity, and applications of heterocyclic compounds.

Target audience: Undergraduate, graduate, and doctoral students in chemistry; pharmacy and chemical engineering students; researchers; medicinal chemists; and pharmaceutical scientists.

Metin Balcı was born in Erzurum, Turkey, in 1948. He obtained his Diplom-Chemiker degree (1972) and PhD (1976) from the University of Cologne where he completed his doctoral studies under the supervision of Professor E. Vogel. He conducted postdoctoral research with Professors Harald Günther, Waldemar Adam, and W. M. Jones. In 1980, he joined Atatürk University’s Department of Chemistry, becoming full professor in 1987. He held visiting positions at the University of Cologne (1986) and Auburn University, USA (1996–1997), and in 1997 joined Middle East Technical University in Ankara.

He has received multiple awards, including the Junior Research Prize (1983) and Science Prize (1989) from Scientific and Technological Research Council of Turkey, the Science Prize from the Ministry of Culture (1991), and a Distinguished Teaching Award (2010). He is an elected member of the Turkish Academy of Sciences, and his research focuses on cyclitols, endoperoxides, strained cyclic compounds, bromine chemistry, and heterocycles. He has published over 280 scientific papers and authored books, including Basic ¹H- and ¹³C-NMR Spectroscopy (Elsevier, 2005) and The Reaction Mechanisms in Organic Chemistry (Wiley-VCH, 2022).