Fathy A. Khalifa

Reactions with halogenated compound: Synthesis of several new pyrazolo[3,2-c] triazine and 2-benzenesulfonylglyoxal arylhydrazone derivatives

Diazotized primary artomatic amines4 coupled with the ketosulfones1–3 in ethanol in the presence of sodium acetate at 0°C to afford the corresponding hydrazones5–7. Also diazotized 3-aminopyrazoles14 coupled with1–3 in ethanolic sodium acetate to give the pyrazolotriazines18–20 in good yields. Compounds5–7 and18 can also be obtained from the reaction of hydrazidoyl halides8–10 and21 with sodium benzenesulfinate. The hydrazones11–13 can easy be oxidized to the hydrazones5–7, using hydrogen peroxide in acetic acid.

Reactions with coumarins : synthesis of several new annelated pyridine and pyrrolylcoumarin derivatives

Benzopyranopyridine, pyrazolo[3,4-d]-pyridine, isoxazolo(5,4-b]-pyridine, pyrido(2,3-d]pyrimidine and pyrrolylcoumarin derivatives were synthesixed from 3-acetylcoumarin and its derivatives with different reagents

HETEROCYCLES FROM NITRILE OXIDES: SYNTHESIS AND REACTIONS OF 2-THIENOYLHYDROXAMOYL CHLORIDE

Abstract Nitroso derivatives of imidazo[1,2-a]pyridine, imidazo[1,2-a]pyrimidine and imidazo[1,2-a]pyrazine were obtained in good yields by the action of 2-thienoylhydroxamoyl chloride (2) on 2-aminopyridines, 2-aminopyrimidine and 2-aminopyrazine, respectively. Benzotriazine, benzothiadiazine and quinazoline were obtained from 2 via its reactions with o-phenylendiamine, o-aminothiophenol and methylanthranilate, respectively. 2 was treated with ethylenic and acetylenic dipoloraphiles to afford 3-thienoylisoxazolines and isoxazole, respectively. The structures of the products were assigned and confirmed on the basis of their elemental analyses, spectral data and alternative synthesis wherever possible.

Synthesis and dyeing characteristics of some new asymmetrical 3-cyanoformazans

Abstract A series of new asymmetrical 3-cyanoformazans have been synthesised by coupling diazotised 5-amino-3-phenylpyrazole and 3-aminobenzimidazole with cyanoacetanilide and treatment of the resulting azo derivatives with arene diazonium salts. The behaviour of the newly synthesised formazans as direct, acid and basic dyes is reported.

Reactions with acetoacetanilide: Synthesis and antibacterial activity of some new pyran, pyrano[2,3-c]pyrazole and pyrano[2,3-c]-pyridine derivatives

The reaction of acetoacetanilide (1) with the α-cyanocinnamonitrile derivatives2 yielded the Michael adducts4 which could be converted into the pyrano[2,3-c] pyrazole derivatives5 via their reaction with hydrazine hydrate. Cyclisation of4 afforded the cyanoaminopyrans9 which could in turn be converted into the corresponding pyridine derivatives10. The pyranopyrazoles9 reacted with different activated nitrile derivatives (3a-c) to give the pyrano[2,3-c]pyridine derivatives13, 16 and19 respectively. The biological activity of the synthesised heterocyclic derivatives was investigated and discussed.

REACTIONS WITH CYANOTHIOACETAMIDE DERIVATIVES: A NEW ROUTE FOR THE SYNTHESIS OF 2-THIAZOLIN-4-ONE THIAZOLO[4,5-B]PYRIDINE, THIAZOLINONYLPYRAZOLE AND PYRANO[2,3-d]-1,3-THIAZOLE DERIVATIVES

Abstract Several new 2-thiazolin-4-one, thiazolo[4,5-b]pyridine, thiazolin-4-on-2-yl pyrazole and pyrano[2,3-d]-1,3-thiazole derivatives were synthesised via the reactions of 2-α-cyanoacetonyl-2-thiazolin-4-one with a variety of α,β-unsaturated nitriles and other reagents. Structural elucidations were based on elementary analyses and spectral data studies.

REACTIONS WITH HYDRAZIDOYL HALIDES VII1: SYNTHESIS OF SEVERAL NEW ANNELATED PYRAZOLE, QUINAZOLINE AND THIAZOLE DERIVATIVES

Abstract Several new annelated pyrazole, 3H-quinazolinone and thiazole derivatives are synthesized via the reaction of 2-bromothienylglyoxal-2-arylhydrazones with different reagents. The structures of the newly synthesized compounds were established on the basis of elemental analyses and spectral data studies.

Synthesis and reactions of some pyridazine derivatives

Abstract3,4-Diphenyl-5-cyanopyridazin-6-one 3 was prepared from the reaction of cyano-acetamide2 with benzilhydrazone in dry pyridine. A series of its derivatives was prepared. Tolyl and benzene sulphonyl derivatives6a and6b are also prepared. 3,4-Diphenyl-5-cyano-pyridazin-6-thione5 was obtained from3 by the action of P2S5 while 3,4-diphenyl-5-cyano-6-chloropyridazine4 was obtained from3 by the action of POCl3. The reaction of4 with hydrazine hydrate directly afforded the pyrazolopyridazine derivative7. Compound4 also reacted with phenylhydrazine, aniline, thiophenol and anthranilic acid to yield pyridazine derivatives8, 9, 10 and11, respectively. On treatment of compound11 with acetic anhydride it cyclised to afford pyridazino pyrimidine derivatives12.

BENZIL IN HETEROCYCLIC SYNTHESIS: SYNTHESIS AND REACTIONS OF 3, 4-DIPHENYL-5-CYANO-PYRIDAZINE-6-THIONE

Abstract 3.4-Diphenyl-S-cyanopyridazine-6-thione (7) is prepared via three routes either by the reaction of benzil hydrazone (1) and cyanothioacetamide (2) or by the reaction of benzil (3) with cyanothioacetamide to give (4) which reacts with hydrazine hydrate to give the intermediate (5) that cyclised to (7) by boiling with glacial acetic acid or by the action of P,S, on 3.4-diphenyl-S-cyanopyridazin-6-one1 (6). Methylation of the SH group in (7) afforded (8) while its reaction with ethyl bromoacetate gave the pyridazine derivative (9). Treatment of (8) and (9) with hydrqzine hydrate produced directly the pyrazolopyridazine derivative (lo), Treatment of (9) with NH3/EtOH afforded the amidic derivative (11) while its treatment with dil. HCI gave 3.4-diphenyl-5-cyanopyridazin-6-one (6). 1 Treatment of (9) with NH,/heat then acidification gave carboxylic derivative (12). Treatment of (9) with p-chloroaniline and p-toluidine gave p-chloroanilino and toluidino derivatives (13 a,b).

Microdetermination of vitamin A (retinol) with N-bromosuccinimide

A novel method for the microdetermination of vitamin A in its pure state and pharmaceutical preparation using NBS is reported. The new method is easy, simple and accurate.