Multicomponent synthesis of styryl linked benzo[h]pyrazolo[3,4-b]quinoline-5,6(10H)-diones by liquid assisted grinding

Herein we report an interesting multicomponent reaction of alpha,beta-unsaturated aldehydes, 2-hydroxy-1,4-naphthoquinone and 5-aminopyrazoles by liquid assisted grinding. This three-component reaction provides styryl linked benzo[h]pyrazolo[3,4-b]quinoline-5,6(10H)-diones by grinding for 20-30 min in the presence of water (eta = 0.25 mu L mg(-1)). The resultant three-component product has four bioactive moieties such as 1,2-naphthoquinone, pyridine, pyrazole and styryl. One-pot green reaction conditions, short reaction time, easier purification process, and good yields are the other notable features of this methodology. All the products were characterized by IR, NMR and HRMS. Furthermore, the structure was unambiguously confirmed by recording single crystal XRD of two compounds.

Automated summary

In this study, an interesting multicomponent reaction was reported, in which styryl linked benzo[h]pyrazolo[3,4-b]quinoline-5,6(10H)-diones were synthesized by liquid assisted grinding of alpha,beta-unsaturated aldehydes, 2-hydroxy-1,4-naphthoquinone and 5-aminopyrazoles. The resulting products have multiple bioactive moieties and the methodology offers green reaction conditions, short reaction time, and good yields.