A Metal‐Free Amination of 1,2‐Diaza‐1,3‐dienes Using Hydrazine Hydrate Through N−N Bond Cleavage

• Published in: Asian journal of organic chemistry 2024-10, Vol.13 (10), p.n/a
• Main Authors: Kumar, Abhishek, Jaiswal, Arvind Kumar, Kushawaha, Ajay Kishor, Singh, Anushka, Kant, Ruchir, Shukla, Sanjeev K., Sashidhara, Koneni V.
• Format: Article
• Language: English
• Subjects: 4,5-Diamino pyrazole; Density functional theory; DFT computational; Dienes; Heterocyclic compounds; Hydrazines; Metal free; N−N bond cleavage; Pyrazole; Pyrazolo[3,4-d]-1,2,3-triazole; Synthesis
• ISSN: 2193-5807; 2193-5815
• DOI: 10.1002/ajoc.202400169

Herein, we have developed a metal‐free, atom‐economical, intrinsically sustainable approach for synthesizing unprotected 4,5‐diamino pyrazoles from readily available 1,2‐diaza‐1,3‐dienes. This approach utilizes inexpensive hydrazine hydrate as the aminating source. Further, we have explored the reactivity of 4,5‐diamino pyrazole to synthesize fused pyrazolo[3,4‐d]‐1,2,3‐triazole heterocyclic compounds. We have also successfully demonstrated the synthetic utility of this methodology in synthesizing two drug analogs: analgesic difenamizole and anti‐psychotic CDPPB. The role of the phenyl ring of 3‐substituted‐1,2‐diaza‐1,3‐diene was explained with the help of control experimental and density functional theory (DFT) computation studies. We have developed an efficient, cost‐effective, and scalable approach for synthesizing unprotected 4,5‐diamino pyrazoles from 1,2‐diaza‐1,3‐diene using hydrazine hydrate as the aminating source.