Ehab Abdel-Latif

Design and synthesis of new 4-pyrazolin-3-yl-1,2,3-triazoles and 1,2,3-triazol-4-yl-pyrazolin-1-ylthiazoles as potential antimicrobial agents.

New pyrazolyl-1,2,3-triazoles and 1,2,3-triazol-4-yl-pyrazolylthiazoles were synthesized through multi step reactions using 1-tolylyl-4-acetyl-5-methyl-1,2,3-triazole as a precursor. All the newly synthesized compounds were characterized by spectral and elemental analyses. The structure of 11b was evidenced by X-ray crystallographic study. The newly synthesized compounds were evaluated for their antimicrobial activities and also their minimum inhibitory concentration (MIC) against most of test organisms was performed. Amongst the tested compounds 5a, 5c, 11b and 11c displayed excellent antimicrobial activity.

Synthesis of new 5-thiazolyl azo-disperse dyes for dyeing polyester fabrics

Diazotized aryl amines were coupled with 2-aminothiazoles 1 and 2 to give the corresponding thiazolylazo dyes 3 and 4, respectively. 2-Amino-5-arylazothiazoles 5 reacted with chloroacetyl chloride to afford the chloro-acetamide derivatives 6 which further reacted with 2-mercaptobenzothiazole to furnish a new series of 5-arylazothiazolyl dyes 7. The azo structure of the dyes (rather than the tautomeric hydrazo structure) was assessed by ab initio DFT calculations at the B3LYP/6-31G* level. These dyes were applied to polyester fabric as disperse dyes and their fastness properties were evaluated.

Synthesis and molluscicidal activity of some new thiophene, thiadiazole and pyrazole derivatives

The base-catalyzed reaction of benzoyl acetone 1 with phenyl isothiocyanate yields the non-isolable intermediate 2. Treatment of 2 with dilute HCl afforded the corresponding thiocarbamoyl derivative 3. Reaction of the intermediate 2 with phenacyl bromide, ethyl bromoacetate, chloroacetonitrile, chloroacetyl chloride, bromodiethyl malonate and chloroacetone afforded the corresponding thiophene derivatives 5, 8, 15 and 17. The thiocarbamoyl derivative 3 reacts with arylazophenacyl bromide and/or hydrazine hydrate to afford the corresponding thiadiazole and pyrazole derivatives 20a-c and 22, respectively. These new synthesized compounds show generally a moderate molluscicidal activity to Biomphalaria alexandrina snails.

Versatile 2-amino-4-substituted-1,3-thiazoles: synthesis and reactions

Syntheses and reactions of 2-amino-4-substituted-1,3-thiazoles are reviewed in a formal way. The title compounds are most easily accessible by various approaches, and even waste-free solid-state procedures have been developed. The substitution in 4-position has synthetic reasons and therefore most interest accumulates around these derivatives of 2-aminothiazole. The high reactivity of both the amino group and the positions 3 and 5 of the 1,3-thiazole ring are used for numerous syntheses in a comprehensive way. The reactions are subdivided in groups that cover reactions at the amino substituent without touching the thiazole ring, reactions which involve both nitrogens in the formal amidine system to give thiazolo-pyrimidinones and -imidazoles as well as more involved polycondensed N,S-heterocycles with multiple possibilities for substituents, and substitution reactions at the 5-position of the thiazole ring. Most of the imaginable reaction types have been successfully applied and used, as many of the synthesized compounds exhibit interesting biological activity in various fields.

Versatile Synthesis of N,S-Heterocycles Containing the Antipyrine Moiety

A series of novel sulfide derivatives of expected biological activity were synthesized via the reaction of 4-(chloroacetyl)antipyrine (1) with several sulfur nucleophiles. The quantitatively available 2-aminothiazole derivatives 10 and 11 were coupled with pyrazolopyridinyl and aromatic diazonium salts to furnish a new series of the corresponding pyrazolopyridinylazo and arylazo-thiazole dyes 12 and 13. The reaction of 4-(cyanoacetyl)antipyrine (14) with phenyl isothiocyanate afforded the nonisolable adduct 15, which was used as a precursor for the synthesis of polyfunctionally substituted ketene N,S-acetal, dihydrothiazole, and thiazolidinone ring systems.

Synthesis of 5‐arylazo‐2‐(arylidenehydrazino)‐thiazole disperse dyes for dyeing polyester fibres

Purpose – The purpose of this paper is to synthesise some new 5‐arylazothiazole disperse dyes and study their application in dyeing polyester fibres.Design/methodology/approach – A series of 5‐arylazo‐2‐(arylidenehydrazino)‐4‐substituted‐thiazole dyes were prepared by cyclocondensation of hydrazonoyl bromides with various thiosemicarbazone derivatives.Findings – The dyed fibres exhibit very good washing, perspiration, sublimation and light fastness properties with little variation in the moderate to good rubbing fastness. The ease of preparation and the acceptable fastness properties makes these dyes particularly valuable.Research limitations/implications – In the present paper, the synthesis of 5‐arylazo‐2‐(arylidenehydrazino)‐thiazole disperse dyes was achieved by one step pathway. In addition, the variations in substituents on the aryl and thiazole moieties could also be studied.Practical implications – The new arylazo‐thiazole disperse dyes are superior in terms of yield, purity, colour strength, and ...

Synthesis and reactions of some thiocarbamoyl derivatives

Thiocarbamoyl derivatives (2a-c) were prepared in a good yield by a modified method. Their behavior toward aromatic diazonium salts, hydrazine hydrate and chloroacetyl chloride were investigated. The structures of the ring systems have been confirmed by analytical and spectral methods.

Thiocarbamoyl derivatives as synthons in heterocyclic synthesis

The synthetic utility of thiocarbamoyl derivatives is reported in a formal way. The title compounds are used as precursors for the synthesis of many heterocyclic rings. The reactions of the title compounds are subdivided into groups that cover reactions yielding monocyclic heterocycles e.g., pyrroles, thiophenes, pyrazoles, imidazoles, thiazoles, pyridines, pyrimidines, oxazines, and even fused heterocycles, e.g., thiazolopyrimidines and thiazolotriazines.

Thiocarbamoyl in Organic Synthesis: Synthesis of Some New Arylazothiophene and Arylazopyrazole Derivatives

Arylazothiocarbamoyl derivatives 4a–e were utilized for the synthesis of several new thiophene and pyrazole derivatives. Compound 4 reacted with phenacyl bromide, ethyl bromoacetate, chloroacetonitrile, chloroacetone and hydrazine hydrate to yield thiophene and pyrazole derivatives 7, 10, 12, 14, and 16, respectively.

Novel Antimicrobial Agents: Fluorinated 2-(3-(Benzofuran-2-yl) pyrazol-1-yl)thiazoles

A new series of 2-pyrazolin-1-ylthiazoles 8a–d and 13–16 was synthesized by cyclization of N-thiocarboxamide-2-pyrazoline with different haloketones and 2,3-dichloroquinoxaline. The structures of the new compounds were confirmed by elemental analyses as well as NMR, IR, and mass spectral data. The newly synthesized compounds were evaluated for their antimicrobial activities, and also their minimum inhibitory concentration (MIC) against most of test organisms was performed. Amongst the tested ones, compound 8c displayed excellent antimicrobial activity.