Pyrazolo[1,5- <i>a</i> ]pyridine: Recent synthetic view on crucial heterocycles

Pyrazolo[1,5-a]pyridine is one of the important core of nitrogen ring junction heterocyclic compounds. Due to novel and uncomplicated methods, ring junction motifs have an emerging engrossment in synthetic as well as medicinal chemistry. Even though all the ring junction structures are not available in natural products they have been significant from a biological viewpoint. In 1948, the first report of pyrazolo[1,5-a]pyridine was being studied. The characteristic of these motifs are found to be highly used in medicinal chemistry and drug molecule production. It makes them versatile, easy to prepare and create a further ring extension like electron gaining and donating in pyrazolo pyridine does make a different in chemical property. Thus, the growing wealth of pyrazolo[1,5-a]pyridine analog focuses on synthetic strategies in current years. This review is planned for the comprehensive discussion about developments, synthesis and reactivity of pyrazolo[1,5-a]pyridine,and mainly the contributions after 2006.