Synthesis, Spectroscopic Characterization, and Time-Dependent DFT Calculations of 1-Methyl-5-phenyl-5-pyrido[1,2-]quinazoline-3,6-dione and Its Starting Precursor in Different Solvents.

In this study, 2-mercapto-3-phenyl-2,3-dihydro-1-quinazolin-4-one (), which exists as a thiol and thione tautomer, was treated with acetylacetone to give the target compound, namely, 1-methyl-5-phenyl-5-pyrido[1,2-]quinazoline-3,6-dione (). The spectroscopic data, including UV/Vis, IR, H NMR, C NMR, and mass data, of this compound were recorded. The molecular structures of the starting material () and the product () were optimized by using density functional theory (DFT) by employing the B3LYP exchange correlation with the 6-311G (d, p) and 6-31G++ (d, p) basis sets.

Synthesis, Characterization, Antimicrobial Screening and Free-Radical Scavenging Activity of Some Novel Substituted Pyrazoles.

The present work deals with the synthesis of acetoxysulfonamide pyrazole derivatives, substituted 4,5-dihydropyrazole-1-carbothioamide and 4,5-dihydropyrazole-1-isonicotinoyl derivatives starting from substituted vanillin chalcones. Acetoxysulfonamide pyrazole derivatives were prepared from the reaction of chalcones with p-sulfamylphenylhydrazine followed by treatment with acetic anhydride. At the same time 4,5-dihydropyrazole-1-carbothioamide and 4,5-dihydropyrazole-1-isonicotinoyl derivatives were prepared from the reaction of chalcones with either thiosemicarbazide or isonicotinic acid hydrazide, respectively.

Synthesis and antimicrobial evaluation of some pyrazole derivatives.

Reaction of a series of (E)-3-phenyl-4-(p-substituted phenyl)-3-buten-2-ones with p-sulfamylphenyl hydrazine in glacial acetic acid gave the corresponding hydrazones, subsequent treatment of which with 30% HCl afforded pyrazole-1-sulphonamides. On the other hand, refluxing of chalcones with either thiosemicarbazide or isonicotinic acid hydrazide in ethanol containing a few drops of acetic acid gave pyrazoline-1-thiocarboxamides and isonicotinoyl pyrazolines, respectively. The structures of the synthesized compounds were determined on the basis of their elemental analyses and spectroscopic data.

Synthesis and in vitro antimicrobial activity of some pyrazolyl-1-carboxamide derivatives.

A series of 3,5-disubstituted pyrazole-1-carboxamides were obtained by treatment of chalcones with semicarbazide hydrochloride in dioxane containing sodium acetate/acetic acid as a buffer solution. N-acetyl derivatives of pyrazole-1-carboxamides were isolated in good yields either by treatment of the carboxamide derivatives with acetic anhydride or refluxing chalcones with semicarbazide in ethanol containing few drops of acetic acid to give the corresponding hydrazones. Subsequent treatment of hydrazones with acetic anhydride gave the desired N-acetyl pyrazole-1-carboxamides derivatives.

Synthesis and antimicrobial evaluation of some heterocyclic chalcone derivatives.

Some new heterocyclic compounds containing isoxazole, pyrazole and oxadiazole ring systems were prepared from various chalcones. The synthesized compounds have been characterized by elemental analysis and spectral methods. These compounds were screened for their antimicrobial activities.