2,3-dihydro-1H-pyrazoles were highly selectively synthesized via the Pd(0)-catalyzed coupling-cyclization reaction of 4-non-substituted 2-substituted 2,3-allenyl hydrazines with aryl iodides in moderate to good yields.

Pyrazoles are very important class of biologically active compounds and many of their derivatives are in clinical use. Pyrazole derivatives have been shown to exhibit antihyperglycemic [1], hypoglycemic [2] and fungicidal properties [3]. Some of them are also used as insecticides and herbicides [4,5]. Of the condensed pyrazoles, specially pyrano[2,3-c]pyrazole is a fused heterocycle comprising ...

Despite notable recent efforts, a catalytic and convenient strategy for the direct alkylation of unactivated allylic or benzylic sp C–H bonds remains a formidable challenge facing the synthesis community. We herein report an unprecedented allylic/benzylic alkylation using only an organo-photoredox catalyst, which enables coupling of a broad scope of alkenes/arenes and electron-deficient alkenes...

A simple, efficient, and environment friendly protocol for the synthesis of 1,3,5-triarylpyrazole and 1,3,5-triarylpyrazolines in [bimm][PF6] ionic liquid mediated by Cu(OTf)2 is described. The reaction protocol gave 1,3,5-triarylpyrazoles in good to high yields (71-84%) via a one-pot addition-cyclocondensation between chalcones and arylhydrazines, and oxidative aromatization without requiremen...

Pyrano[2,3-c]pyrazoles are obtained via mixing ethyl acetoacetate, hydrazine hydrate, aldehydes or ketones and malononitrile in the absence of solvent. These same products were also obtained by reacting arylidenemalononitriles 3 with 3-methyl-2-pyrazolin-5-ones. NOE difference experiments confirmed that these products exist solely in the 2H form. Similar treatments of 3-amino-2-pyrazolin-5-one ...

The new pyrrolo[3,4-c]pyridines and 2,7-naphthyridine derivatives have been synthesized. 4-Hydroxy-8-methyl-l-oxo-6-phenyl-1,2-dihydro-2,7-naphthyridine-3-carboxylic acid hydrazide (4) was the key intermediate for the synthesis of the novel derivatives of various chemical structures: Schiff bases, 1,3,4-oxadiazoles, pyrazoles, carbohydrazides, semi- and thiosemicarbazides. The structures of the...