Green chemistry approaches to the regioselective synthesis of spiro heterobicyclic rings using iodine as a new and efficient catalyst under solvent-free conditions

Synthesis, crystal structure and antibacterial studies of dihydropyrimidines and their regioselectively oxidized products

The syntheses and investigations of new biologically active derivatives of dihydropyrimidines by Biginelli reaction in the presence of copper triflate are reported. Due to the fact that salicylaldehyde and its derivatives under Biginelli reaction conditions can lead to the formation of 2 types of dihydropyrimidines, the influence of copper triflate on product formation was also investigated. In addition to this, regioselective oxidation of dihydropyrimidines was performed in the presence of cerium ammonium nitrate and novel oxidized dihydropyrimidines were obtained. Single crystals of some of them were obtained and as a result, the structures of them were investigated by X-ray diffraction method, which allows determining the presence of hydrogen bonds in their structures. In addition to this, the presence of hydrogen bonds in their structures affects the formation of the corresponding tautomer during oxidizing of dihydropyrimidines. Since dihydropyrimidines are claimed to be biologically active compounds, activities of the synthesized compounds were studied against Acinetobacter baumanii, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus bacteria.

Recent applications of barbituric acid in multicomponent reactions

This review aims to show representative examples of multicomponent reactions utilizing barbituric acid in the synthesis of various heterocyclic structures.

Synthesis of new thiobarbituric acid derived spiroheterobicyclic compounds and their antimicrobial activity

A series pf novel (7S, 11R)-substituted diphenyl-2,4,8,10-tetraazaspiro [5.5] undecane-3-thio-1,5,9-triones 4a-j and (7S,11R)-substituted diphenyl-2,4,8,10-tetraazaspiro[5.5] undecane-3-thio-1,5 dione, 9-thiones 5a-j were prepared using substituted aldehydes and urea/thiourea in the presence of thiobarbituric acid under solvent free, thermal and microwave conditions catalyzed by ecofriendly K-10 clay. The antibacterial potency of these compounds in vitro on the gram negative strains Escherichia coli and Pseudomonas aeruginosa and gram positive strains Staphyllococcus aureus and Staphylococcus epidermidis was evaluated.

KF/Al2O3 Promoted Aza-Michael Addition of 4-Aryl-7,7-Dimethyloctahydro-Quinazolinones to α, β-Ethylenic Compounds

The aza-Michael addition reaction of 4-aryl-7,7-dimethyl-1,2,3,4,5,6,7,8-octahydroquinazoline-2-one/thione-5-ones to α,β-ethylenic compounds in the presence of KF/Al2O3 furnishes N3-substituted quinazolinone derivatives. Those groups (NO2, MeO) with larger steric hindrance at the o-position of the phenyl ring of quinazolinone have an apparent affect on the chemical selectivity thus giving the N1-subsituted products.