Glycerol mediated, one pot, multicomponent synthesis of dihydropyrano[2,3-c]pyrazoles

Sulfonated Graphene‐Oxide as Metal‐Free Efficient Carbocatalyst for the Synthesis of 3‐Methyl‐4‐(hetero)arylmethylene isoxazole‐5(4H)‐ones and Substituted Pyrazole

“…Most of the conventional method for the preparation of dihydropyrano[2,3‐c]pyrazole involves four‐component reaction using various catalytic system such as tungstate sulphuric acid, Cesium carbonate supported on hydroxyapatite coated Ni 0.5 Zn 0.5 Fe 2 O 4 magnetic nanoparticles, nano MgO, glycerol, silica coated magnetic NiFe 2 O 4 nanoparticles supported H 3 PW 12 O 40 (NFSPWA), maltose, trichloroacetic acid, γ‐Fe 2 O 3 @Cu 3 Al‐LDH, NaF . However, considering ecological issues avoidance of the use of hazardous homogeneous catalyst and toxic metal catalyst is essential to prevent environmental pollution. Based on this conception,it was felt to explore a one pot four‐component, environmentally benign, high yielding MCR route of pyranopyrazoles.…”

Catalyst free, one-pot, facile synthesis of novel pyrazolo-1,4-dihydropyridine derivative form pyranopyrazoles

“…Pyranopyrazoles (1a-n) are prepared by using the given literature procedure [16]. In a conical flask, hydrazine hydrate/phenyl hydrazine (10 mmol), ethylacetoacetate (10 mmol), aromatic aldehyde (10 mmol) and malononitrile were added successively in glycerol (20 mL).…”

“…Therefore, recognizing the development of a clean, green and efficient procedure as the need of the hour, and persisting with our work on heterocyclics [16][17][18] and in continuation of our previous work (Scheme 1), we have been able to produce some pyrazolo-1,4-DHPs from easily available pyranopyrazoles ( Figure 1) [16]. The present protocol is simpler as, use of harsh reaction condition scheme is not a pre-requisite to it (Scheme 2).…”