Click Chemical Reactions:An Emerging Approach and Its Pharmaceutical Applications

Click chemistry provides reactions which are simple, fast, stereospecific, give product in high yields and show many other desirable characteristics. These reactions involve linking of the reactant blocks by formation of carbon heteroatom bond between them. Out of the reactions which satisfy click reaction criteria, copper catalysed 1,3-dipolar cycloaddition of alkyne and azide (HDC reaction) has emerged as a perfect click reaction. Some click reactions which can proceed in absence of metal catalyst (metal free click chemistry) are also being developed. Click chemical reactions have wide applications in many areas of pharmaceutical sciences such as synthesis of lead discovery libraries, polymer therapeutics, drug delivery systems and bioconjugation etc.