A Microwave‐Assisted One‐Pot Three‐Step Metal‐Free [4+2] Annulation for the Sustainable Synthesis of Highly Substituted 1,2,4‐Triazines

Herein we report the first microwave‐assisted one‐pot three‐step metal‐free [4+2] procedure for the synthesis of 5,6‐substituted‐3‐hydrazinyl‐1,2,4‐triazines directly from commercially available aromatic and heteroaromatic ketones. The 3‐hydrazinyl‐1,2,4‐triazine can be isolated or further elaborated, after a simple work‐up, by direct condensation with different aldehydes or ketones to provide highly functionalized hydrazone‐derivatives. This protocol represents a rapid, efficient, and sustainable approach for the development of new highly functionalized 1,2,4‐triazine derivatives with potential biological interest.