3,4-Dihydro-2H-pyran promoted aerobic oxidative aromatization of 1,3,5-trisubstituted pyrazolines and Hantzsch 1,4-dihydropyridines

Hydrazine Hydrate in Asymmetric Synthesis: A Bifunctional Squaramide Catalytic Approach toward Fused Pyrazolines

A unified strategy has been developed to utilize hydrazine hydrate in asymmetric organic synthesis by overcoming the rapid background reaction with dienone. The H-bond donor ability of the cinchona-alkaloid-derived squaramide catalyst unlocks this previously deemed infeasibility. The dissymmetric hydrazine addition to symmetrical dienones tolerates various substitutions, resulting in the formation of optically pure fused pyrazoline derivatives under mild reaction conditions. Furthermore, the scalability of this methodology and a successful demonstration of postsynthetic transformations have been accomplished.

Cyclization of arylhydrazones of cross-conjugated enynones: synthesis of luminescent styryl-1H-pyrazoles and propenyl-1H-pyrazoles

On the basis of available ethynyl vinyl ketones and arylhydrazines, the authors have developed the two-stage synthesis method for styrylpyrazoles possessing fluorescent abilities, as well as the gram-scale synthesis method for fluorescent probes.

Dehydrogenation induced inhibition of intramolecular charge transfer in substituted pyrazoline analogues

Experimental and computational studies reveal that dehydrogenation of the pyrazoline ring modifies its ground and excited state photophysics radically by restricting the ICT process.

A new oxidation system for the oxidation of Hantzsch-1,4-dihydropyridines and polyhydroquinoline derivatives under mild conditions

An oxidation system to synthesize pyridine derivatives has been developed by oxidation of 1,4-dihydropyridines and polyhydroquinoline derivatives in good yields.