Y. A. Mohamed

SYNTHESIS AND RADIATION STABILITY OF NOVEL THIAZOLOPYRIMIDINES WITH EXPECTED ANTIFUNGAL ACTIVITY

Abstract A number of thiazolopyrimidines (II–VII) were prepared through interaction of 6-methyl-4(4′-chlorophenyl)-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylic acid ethyl ester (Ia) with many reagents. The antifungal activity of all prepared compounds have been determined using Dithane M-45 as a standard fungicide. Some compounds showed a high fungicidal activity equivalent to that of the standard towards Aspergillus niger and Aspergillus ochraceus. Also some biologically active compounds were subjected to gamma irradiation and the structures are stable.

“NOVEL SYNTHESIS AND CYCLIZATION REACTIONS OF 3-AMINO-2-MERCAPTOPYRROLE DERIVATIVES”

Abstract Interaction of cyanothioformamides with chalcones gave 3-amino-2-mercaptopyrroles, which have the tautomeric structures (3-aminopyrroline-2-thiones and 3-iminopyrrolidine-2-thiones). The latter was reacted with chloroacetic acid, ethyl chloroacetate, chloroacetamide and 2,3-dichloro-l,4-naphthoquinone to give the corresponding pyrrolothiazines derivatives. On using phenylisocyanate or p-chlorobenzoyl chloride, the corresponding pyrrolothiazole derivatives could be isolated. Replacement of chalcones by maleimides furnished pyrrolopyrrolinediones.

A COMPARATIVE STUDY OF 4-THIOXO-(IMIDAZOLIDINES AND OXAZOLIDINES) AND SOME NUCLEOPHILIC REAGENTS

Abstract The imidazolidines (II) were reacted with amines, H2S and o-phenyhediamines to give 4-substituted imino derivatives (VI), thiohydantoin (VII) and 1-phenyl-3 -substituted-1H-imidazo[4,5-b]-quinoxaline-2-(3H)-ones(XIII), respectively. Interaction of the oxazolidines (V) with amines, o-phenylenediamines and o-aminophenol caused fission of the oxazole ring to produce (XIV, XVII & XIX) respectively.

Recent Trends in Chemistry of Thiazolopyridines

The aim of this review article is to present the syntheses, reactions, and applications of thiazolopyridines.

SOME REACTIONS WITH p-ETHOXYPHENYLCYANO-THIOFORAMIDE: SYNTHESIS OF PYRROLE, PYRROLO[2,3-c]PYRROLE, IMIDAZO[4,5-b]QUINOXALINES AND HYDANTOIN DERIVATIVES

Abstract P-Ethoxyphenylcyanothioforrnamide (1) was reacted with α,β-unsaturated ketone (2) and N-p-chlorophenylmaleimide (4) to furnish pyrrole and pyrrolo[2,3-c]pyrrol-4,6-diones (3) and (5) respectively. Also, interaction of 1 with anthranilic acid and o-phenylenediarnine produced 3-(4′-ethoxyphenyl)-2-thioxoquinazolin-4-one (6) and 2-thioxobenzirnidazoles (7). When, 1 was reacted with iso(thio)cyanates caused cyclization to afford 5-imino-4-thioxoirn-idazolidinones (9). Compound 9 was subjected to some reagents such as hydrazine hydrate, thiosemicarbazide, o-phenylenediamines, hydrogen sulfide and HCl to give 5-hydrazono, 4-thiosemicarbazono, and thiohydantoin derivatives (10–17), respectively.

A COMPARATIVE STUDY BETWEEN IMIDAZOLIDINEIMINOTHIONES AND4-THIOXOIMIDAZOLIDINE-2,5-DIONES TOWARDS SOME NUCLEOPHILIC AND BINUCLEOPHILIC REAGENTS: SYNTHESIS OF SOME NEW IMIDAZO(DIIMINES, DIHYDRAZONES, QUINOXALINES & AZINE) AND DIIMIDAZOLIDINONE

Abstract Reactions of 5-imino-4-thioxoimidazolidine (II) and 4-thioxoimidazolidine-2,5-diones (III) with amines, hydrazine hydrate, hydrazine derivatives, o-phenylenediamines and cupper turnings were investigated.

Cyanoacetanilides Intermediates in Heterocyclic Synthesis. Part 4: Preparation of Some Hitherto Unknown Thiazolidine and Bisthiazolidine Derivatives

Some novel thiazolidine and bisthiazolidine derivatives were synthesized from the reaction of cyanoacetanilide derivative (2) with isothiocyanates in the presence of potassium hydroxide followed by in situ heterocyclization of the resulting adducts with various α-halogenated reagents.

Cyanoacetanilides Intermediates in Heterocyclic Synthesis, Part 3: Novel Syntheses of Thiazolinone and Thiazolo[3,2-a]Pyridine Derivatives

Thiazolo[3,2-a]pyridines 6a–c , 10 , 13 , and 14 have been synthesized via simple methods from the readily accessible 2-[N-(4-ethoxyphenyl)-acetamide-2-yl]-4,5-dihydro-4-thiazolinone 2. The structure of the synthesized compounds was established by analytical and spectral data.

New Imidazolidineiminothione, Imidazolidin-2-one and Imidazoquinoxaline Derivatives: Synthesis and Evaluation of Antibacterial and Antifungal Activities.

A series of new 5-imino-4-thioxo-2-imidazolidinone derivatives 3 with various halogenated and alkylated aromatic substituents at N1 and N3 was synthesized. Imidazolidineiminothione derivatives 3 were prepared from the reaction of N-arylcyanothioformamide derivatives with aryl isocyanates. These compounds were used as key synthons for the preparation of wide variety of new substituted imidazole compounds. Imine hydrolysis of 3 with ethanolic HCl produced the corresponding 4-thioxo-2,5-imidazolidindiones 4. Condensation of 3 with benzophenonhydrazone furnished the corresponding 4-azine derivatives 5. Monohydrazono and dihydrazono derivatives 6 and 8 were obtained upon treatment of imidazolidinone derivatives 3 with hydrazine hydrate. Finally, imidazolidinones 3 were reacted with o-phenylenediamines or pyrazol-5(4H)-ones and afforded the corresponding imidazoquinoxaline and imidazolidin-4-ylidenepyrazolone-5(4H)-one derivatives 11 and 12, respectively. Evaluation of the antibacterial and antifungal activities for the synthesized compounds was carried out to probe their activities. Most of the tested compounds showed significant activities. The best antimicrobial activity was observed for 1-(3-ethoxyphenyl)-6-methyl-1-phenyl-1H-imidazo[4,5-b]quinoxalin-2(3H)-ones (11c) followed by 5-imino-3-(3-methoxy- phenyl)-1-phenyl-4-thioxoimidazolidin-2-one (3f).

Synthesis of Some Biologically Active 4(3H)-Quinazolinones Derived from 2,3-Pyridine Dicarboxylic Anhydride

A novel 3-amino-4(3H)-quinazolinone was synthesized via two routes. The first route involved interaction of 2,3-pyridine dicarboxylic anhydride with anthranilic acid in acetic acid under reflux to give the amide derivative which was subjected to cyclodehydration and treatment with hydrazine hydrate. The second route involved preparation of amide by treatment of 2,3-pyridine dicarboxylic anhydride with methyl anthranilate in glacial acetic acid under reflux, then treated with hydrazine hydrate. Treatment of 3-amino-4(3H)-quinazolinone with isocyanate, isothiocyanate,ethyl chloroacetate and diethyl malonate gave urea, thiourea, thiazole and pyrimidine derivatives, respectively. In addition, some bisquinazolines were synthesized. Antimicrobial activities of some selected compounds were screened.