Exploration of pyrazole based aldo-x bifunctional building blocks for the synthesis of pyrazole annulated molecular architectures

Over the last decade, the synthetic chemist's community has attracted attention towards aldo-x precursors due to their versatility to afforded variety of heterocyclic frameworks. The aldo-x bifunctional building blocks (AXB3s) contain two or more reactive sites with different reactivity, which may offer new opportunities for the introduction of diversity in core skeleton, which may be of great biological and medicinal relevance. In this context, pyrazole based AXB3s such as 4-iodopyrazole-3/5-carbaldehyde may be explored for achieving pyrazole fused/linked heterocyclic skeletons by employing different organic transformations. Specifically, iodo substituted pyrazoles provide a new platform for the installation of desired pattern via transition-metal catalyzed approaches. Herein, we have assembled the strategies towards the development of pyrazole substituted and fused molecular architectures by using 4-iodopyrazole-3/5-carbaldehydes and pyrazole C-3)/C5- carbaldehydes. The photophysical data of some fluorescent pyrazole derivatives have also been discussed.