Access and modulation of substituted 1-methyl-1,6-dihydropyrazolo[3,4- c]pyrazoles

RSC Adv. 2021 Mar 5;11(16):9756-9765. doi: 10.1039/d1ra00314c. eCollection 2021 Mar 1.

Abstract

Despite the pharmacological potential of the pyrazolo[3,4-c]pyrazoles, only a few methods of preparation and direct functionalization of this moiety have been described. We report herein a convenient design of new pyrazolo[3,4-c]pyrazoles with a high therapeutic impact. The effective chosen strategy consists of hydrazine condensations and C-N Ullmann-type cross-coupling reactions with microwave activation. Moreover, chemoselective bromination of the newly formed bipyrazoles followed by Suzuki-Miyaura cross-coupling reactions allowed the synthesis of a variety of modulated heterobicycles.