The pH-activated E/Z isomerization of a series of hydrazone-based systems having different functional groups as part of the rotor (R = COMe, CN, Me, H), was studied. The switching efficiency of these systems was compared to that of a hydrazone-based molecular switch (R = COOEt) whose E/Z isomerization is fully reversible. It was found that the nature of the R group is critical for efficient swi...

Cyclization-carbonylation of α,β-alkynic hydrazones and (o-alkynylphenyl) (methoxymethyl) sulfides with Pd(tfa)2 in DMSO/MeOH afforded methyl pyrazole-4-carboxylates and benzo[b]thiophene-3-carboxylates, respectively, in good yields. A simple change of the ligand (solvent) allowed controlled, effective switching between cyclization-carbonylation-cyclization-coupling (CCC-coupling) reactions and...

Oxidative transformations of the aldehydes, ketones, and their azomethine derivatives such as hydrazones, Schiff bases, azines, and oximes are presented and discussed. The oxidants used have been hydrogen peroxide in the presence of selenium compounds as catalysts, peroxycarboxylic acids, and eerie ammonium nitrate. Some of reported reactions have practical value in the synthesis of phenols, es...

Aldehyde phenyl hydrazones 2a-i undergo oxidative dehydrogenation with Chloramine-T to give nitrile imines, which are trapped in situ by ethyl oleate 1 to afford 8-(5-Aryl-4-octyl-2-phenyl-3,4-dihydro-2Hpyrazol-3-yl)-octanoic acid ethyl esters 3a-i in good yield. The structures of the cycloadducts were confirmed by spectral studies and elemental analysis.

A number of new substituted 1,2,4-triazole {[(1,2,4-triazolyl)ethyl]tetrazolyl} derivatives, their sugar hydrazones, and their acyclic C-nucleoside analogues were synthesized and tested for their antimicrobial activity against Bacillus subtilis (Gram-positive), Pseudomonas aeruginosa (Gram-negative), and Streptomyces species (Actinomycetes). The synthesized compounds displayed different degrees...

A novel direct transformation of hydrazones to acyloxylated pyrazoles by copper-catalyzed regioselective olefinic C(sp(2))-H bond cycloamination and acyloxylation was performed under mild conditions, which combines the formation of the pyrazole skeleton and installation of an acyloxyl group in a single step, using facile carboxylic acids as the acyloxylation reagents.

2-Substituted azetidin-3-ones can be prepared in good yields and enantioselectivities (up to 85% ee) by a one-pot procedure involving the metalation of the SAMP/RAMP hydrazones of N-Boc-azetidin-3-one, reaction with a wide range of electrophiles, including alkyl, allyl, and benzyl halides and carbonyl compounds, followed by hydrolysis using oxalic acid.

Background: Pyrazole is a simple aromatic ring an organic compound of the heterocyclic series that characterized five-membered ring structure which comprises located adjacent two nitrogen atoms and three carbon atoms. In recent years interest in the pyrazole chemistry excessively has increased due to many a wide range of properties. Because they have a wide range of specific properties such as ...