Heterocycles green chemistry principles

Different methods can be used to synthesize oxygenated heterocycles. Nowadays, the reagents have to be employed in catalytic amounts, and transition metal catalysts have to be considered to form either C—C bonds or C—O bonds. Chemists have to tune up efficient catalytic reactions to be in accordance with the green chemistry principles. 

Use of safer chemicals including solvents satisfies one of the criteria of green chemisfry principles. From green chemistry perspective, solvent-free chemical fransformafions are indisputably more desirable than reactions in any kind of solvents. However, feasibility of solvenf-free reactions is often complicated by problems with reaction (especially exothermic) control, mass transfer limifafion, viscosity and melting point of reacfanfs, etc. Water is the solvent of first choice provided by nature. This is the most commonly used green solvent and heterocyclic S5mthesis in aqueous medium is discussed in details in Chapters 7 and 8 of this book. Unfortunately, very often water is not suitable for organic reactions and choice of another more efficient solvent becomes critical. 

---