Nadia H. Metwally

Synthesis and antimicrobial activity of some new N-glycosides of 2-thioxo-4-thiazolidinone derivatives

5-Arylidene-2-thioxo-4-thiazolidinones 3a-f react with each of 2,3,4,6-tetra-O-acetyl-alpha-D-glucopyranosyl and alpha-D-galactopyranosyl bromides 4a,b in acetone in the presence of aqueous potassium hydroxide at room temperature to afford N-(2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl) or N-(2,3,4,6-tetra-O-acetyl-beta-d-galactopyranosyl) 2-thioxo-4-thiazolidinone derivatives 5a-f. Similarly, the reaction of 5-cycloalkylidene-2-thioxo-4-thiazolidinones 7a,b with 4a gave the corresponding N-glucosides 8a,b. Also, 5-pyrazolidene rhodanines 10a-e react with 4a to afford the new N-glucosides 11a-e. Treatment of compounds 15 and 16 with 4a in the presence of few drops of triethylamine or in KOH solution accomplished the mono- and bis-nucleosides 17 and 18, respectively. Some selected products were tested for their antimicrobial activities.

Novel Synthesis of N-Arylpyrrole, Pyrrolo[1,2-a]quinazoline, and Pyrrolo[3,4-d]pyridazine Derivatives

Abstract Phenacyl-malononitrile derivatives 1a,b react with dimethyl formamide dimethyl acetal (DMFDMA) in refluxing toluene to afford the enaminones 2a,b respectively. Compounds 2a and 2b react with the aromatic amines (aniline, p-toluidine, p-anisidine) in refluxing ethanol to afford the pyrroles 4a–f and with anthranilonitrile and methyl anthranilate to afford the pyrrolo[1,2-a]quinazolines 5a,b and 6a,b respectively. The pyrrole derivatives 4a–f react with hydrazine hydrate and phenyl hydrazine in refluxing ethanol to afford the pyrrolo[3,4-d] pyridazine derivatives 7a–f and 8a–f respectively.

Synthesis of Some New N‐Substituted Pyrroles, Pyrrolo[1,2‐a]quinazoline, and Diaza‐as‐indacene Derivatives

Abstract 2‐Phenyl‐1,1,3‐tricyano‐3‐bromopropene 1 reacts with the aromatic amines 2a–f and 6a–c to afford the N‐substituted pyrroles 4a–d, the pyrrolo[1,2‐a]quinazoline derivatives 5a, b, and the diaza‐as‐indacene derivatives 7a–c and 8a–c, presumably via elimination of hydrogen bromide followed by cyclization of the formed acyclic intermediates. All structures are confirmed by analytical and spectral data.

Synthesis of some new fused thiopyrano[2,3-d]thiazoles and their derivatives

A series of some new fused thiopyrano[2,3-d]thiazole derivatives have been synthesized by a stereo-selective hetero-Diels-Alder reaction of 5-(2,4-dihydroxy-benzylidene)-4-thioxo-thiazolidine derivatives 3a,b with acrylonitrile, ethyl acrylate, N-phenylmale-imide, ω-nitrostyrene and N-phenyl-1, 3, 4-triazole-2,5-dione. 5-Amino-9-hydroxy-dihydro-benzopyrano[3′,4′:4,5]thiopyrano[2,3-d]thiazol-6-one derivatives 14a,b have been synthesized by Michael addition of 3a,b with malononitrile. Structures and conceivable mechanisms are discussed.

A simple and green procedure for the synthesis of 5-arylidene-4-thiazolidinones by grinding

Abstract An improved green Knoevenagel condensation of various aromatic aldehydes with 4-thiazolidinones in the presence of anhydrous ammonium acetate can be achieved by grinding at room temperature in the absence of solvents. This process is simple, efficient, economical, and environmentally benign compared to classical reactions.

Reaction of Anthranilonitrile with Some Active Methylene Reagents: Synthesis of Some New Quinoline and Quinazoline Derivatives

Abstract Anthranilonitrile (1) reacts with ethyl cyanoacetate and its dimer, malononitrile, cyanothioacetamide and N‐arylidene cyanoacetohydrazides 12a–c to afford pyrano[2,3‐b]quinoline 5, cyanomethyl‐quinazoline 10, pyrazolo[2,3‐a]quinazoline 12 and triazolo[4,3‐a]‐quinoline derivatives 16a–c, respectively. Structures and conceivable mechanisms are discussed.

A Facile One-Pot Synthesis of Some New Spiro-thiazolidin-4-ones and Benzimidazoles of Biological Interest

In a one-pot procedure, aromatic amines 1a–c , 9-fluorenone ( 2 ) and 2-mercaptoacetic acid (3) were converted into fluorenespiro-thiazolidinone derivatives 4a–c , which undergo condensation, oxidation and thiation to afford 6a–i , 7a–c , and 4-thioxo 8a–c , respectively. A new fluorenespiro-thiazolo-benzimidazole 10 was also obtained in one step via cyclocondensation of 1,2-phenylenediamine, 9-fluorenone and 2-mercaptoacetic acid. The obtained products seem to be interesting from the biological point of view.

Polarity and steric effect of the lateral substituent on the mesophase behaviour of some newly prepared liquid crystals

Eight homologous series of 2- (or 3-) substituted phenyl 4ʹ-(4ʺ-alkoxy phenylazo) benzoates (Ina–h) were prepared in which, within each homologous series, the length of the terminal alkoxy group varies between 6, 8, 10 and 12 carbons, while the other substituent, X, is a laterally attached polar group that alternatively changed from CH3, H, F, Br and CN. Compounds prepared were characterised by infrared and 1H-NMR spectroscopy, and their mesophase behaviour investigated by differential scanning calorimetry and identified by polarised light microscopy. The results were discussed in terms of polarity and steric effects. The stability of the mesophase was correlated once with the dipolar anisotropy of the whole molecule and another with the dipolar anisotropy of the substituent, X. A comparative study was made between the investigated compounds and their previously prepared linear 4-substituted isomers, namely 4-substituted phenyl 4ʹ-(4ʺ-alkoxy phenylazo) benzoates (Ini–k).

A Novel Synthesis of 1,4-Bis(thiopyrano[2,3-d]thiazolyl)benzene Derivatives

The novel 5-(4-formylphenyl)methylene-thiazolidine-2,4-dithione 3 and l,4-bis[(4-thioxo-thiazolidinyl)methylene]benzene derivatives 4a,b were synthesized by condensation of each of 4-thioxo-thiazolidin-2-one (la) and thiazolidine-2,4-dithione (1b) with terephthalaldehyde (2), in good yields depending on the molar ratio of 1 to 2. The cycloaddition of the newly synthesized compounds to N-arylmaleimides, ethyl acrylate, ω-nitrostyrene and malononitrile was studied. The structures of the synthesized compounds were established by elemental analyses and spectral data.

2-Keto-3-mercaptocinchoninic Acids as Precursors for Novel Thiazino[6,5-c]quinoline-1,5-dione Derivatives

Abstract 2-Keto-3-mercaptocinchoninic acid derivatives 1a and b react with Schiffs bases 2a–d in toluene at refluxing temperature to give thiazino[6,5-c]quinoline derivatives 4a–h. Also, refluxing of 1a and b with arylazomalononitriles 5a–d in acetic acid afforded the thiazolo[6,5-c]quinoline derivatives 7a–d. The structure of all the newly synthesized products was confirmed based on elemental and spectral data. GRAPHICAL ABSTRACT