F. A. Amer

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.

A facile and convenient synthesis of substituted tetrazole derivatives from ketones or α,β-unsaturated ketones

Abstract Triazidochlorosilane (SiCl 4 - NaN 3 in situ) is a new and efficient reagent for the direct conversion of ketones or α,β-unsaturated ketones to the corresponding tetrazole derivatives in nearly quantitative yield.

A NOVEL APPROACH FOR THE SYNTHESIS OF 5-SUBSTITUTED TETRAZOLE DERIVATIVES FROM PRIMARY AMIDES IN MILD ONE-STEP METHOD

Abstract A new mild one-step method for the conversion of primary acid amides to 5-substituted tetrazoles in nearly quantitative yields employing triazidochlorosilane (TACS) is reported.

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.

Synthesis of triazidochlorosilane (TACS). A novel silicon mediated one pot conversion of aldehydes to nitriles

Abstract Synthesis, structure elucidation of triazidochlorosilane (TACS) and a novel conversion of aldehydes to nitriles in one pot reaction on treatment with TACS (SiCl 4 NaN 3 in Situ) reagent in acetonitrile are described.

Synthesis and Antioxidant and Antitumor Activity of Novel Pyridine, Chromene, Thiophene and Thiazole Derivatives

2‐Tosylacetonitrile (1) when reacted with α,β‐unsaturated nitriles 2a–c or a mixture of formaldehyde and 3‐amino‐2‐substituted‐pent‐2‐endinitriles 6a,b yielded pyridine derivatives 3a–c and 9a,b, respectively, while when subjected to react with salicylaldehyde yielded chromene derivatives 4 and 5, subsequently. The behavior of thiocarbamoyl derivative 10 derived from 1 towards some α‐halogenated compounds have been investigated as well as its behavior towards elemental sulfur and phenyl isothiocyanate. Newly synthesized compounds were screened for their antioxidant activity, erythrocytes haemolysis and bleomycin‐independent DNA damage. Some of the tested compounds exhibited promising activities.

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 ...

REVISED SYNTHESIS OF SOME NEW DERIVATIVES OF BIOLOGICAL INTEREST 2-HETEROCYCLIC BENZOTHIAZOLYL DERIVATIVES OF BIOLOGICAL INTEREST

Abstract Substituted benzothiazole at position 2 by a heterocyclic ring has been prepared by the action of bifunctional compounds on the active intermediate a-2-benzoth: azolyl-β-arylaminoacrylonitrile (III). Compound III was obtained by refluxing a-2-benzothiazolyl-β, β-dimethylthioacrylonitrile (II) with aromatic amines in ethanol for a long time. Refluxing equimolar amounts of I11 and hydrazine, hydroxylamine, guandine ethylenediamine and ethanolamine in presence of DMF yielded the corresponding 2-pyra- 2010, isoxazolo, pyrimidino, 1,4-diazepino and 1,4-oxazepinobenzothiazole (V-IX), respectively. The structures of all newly prepared compounds have been confirmed by analytical and spectral data.

Nitriles in organic synthesis : A convenient route to some heterocycles incorporating a benzothiazole moiety

2-(Benzo[d]thiazol-2-yl)-4-chloro-3-oxobutanenitrile (2) was utilized for the synthesis of several new benzothiazole derivatives. Compound 2 reacted with aniline, hydrazine hydrate, ethanolamine, and ethyl glycinate hydrochloride to yield benzothiazole derivatives 3–6, respectively.

Use of reductive properties of iodotrichlorosilane II: Chemoselective reduction of α,β-unsaturated ketones and nitriles

Abstract A new synthetic procedure for the selective reduction of α,β-unsaturated ketones and nitriles, using iodotrichlorosilane (ITCS generated in situ from SiCl4-NaI) under mild conditions to produce the corresponding saturated ketone and nitrile compounds in quantitative yields, is described.