In summary, we highlight the differences in chemical reactivities of pyrazolyl α-aminonitrile under reductive reaction environment arising due to different C4-halogen substituents and suggest a plausible mechanism for this unexpected observation. Our work not only suggests unexpected reactivity of C4-Bromopyrazolyl-αaminonitrile in reductive environment but also highlights the importance of exploring possible rearrangements within intermediates to reveal non-intuitive reaction mechanisms. We believe a combination of experiments and computations is essential for reaction discovery and process design strategies, both of which are useful for modern-day drug discovery.