Zarif H. Khalil

SYNTHESIS AND REACTIONS OF SOME THIENO[2,3-d]PYRIMIDINE DERIVATIVES

Abstract 5-Cyano-4-oxo-6-phenyl-2-thioxo-1,2,3,4-tetrahydropyrimidine (I) reacts with P2S5 in pyridine to give pyrimidine-2,4-dithione (II). Further reaction of II with ethyl chloroacetate, chloroacetanilide, phenacyl bromide, bromoacetone and chloroacetonitrile gave the corresponding thieno[2,3-d]pyrimidine derivatives (III-VI). Interaction of compound IVa with hydrazine hydrate in ethanol or diluted ethanol gave the hydrazide and hydrazino derivatives (VII, IX), which reacted with aromatic aldehydes to give the corresponding hydrazones (VIIIa-c, Xa-c ). Alkaline hydrolysis of IV, using KOH gave the acid XI with extrusion of thioglycolic acid.

Effect of cyanine dye-solvent interaction on the electrochemical corrosion behaviour of low-carbon steel in acid medium

Abstract The effect of the solvent used in the preliminary treatment with 1-ethyl-2(2′-hydroxystyryl)quinolinium cyanine dye solution on the electrochemical corrosion behaviour of low-carbon steel in HCl solution as the corrosive medium has been studied. Weight loss measurements, anodic potentiostatic polarization curves and the cathodic current values showed that cyanine dye in protic solvents (isobutanol, isopropanol, n-butanol, water and methanol) gives a more inhibitive effect than when dissolved in aprotic ones (dimethylformate, dimethylsulphoxide, 2-butanone, acetone and dioxane). The relative permittivities of the different solvents are not the main factor affecting the inhibitive action. It was found that in the case of protic solvents, isobutanol gives a higher inhibitive action and methanol gives a lower one; in the case of aprotic solvents, N, N′-dimethylformamide gives the higher inhibitive effect. This behaviour was confirmed by the polarization studies and the values of the cathodic protective currents.

NEW PYRIMIDINE DERIVATIVES: SYNTHESIS AND APPLICATION OF THIAZOLO[3,2-a]-TRIAZOLO[4,3-a]-PYRIMIDINE AS BACTERICIDES, FUNGICIDES AND BIOREGULATORS

Abstract 5-Cyano-4-oxo-6-phenyl-2-thioxo-l,2,3.4-tetrahydro pyrimidine1 (I) reacts with alkyl or alkaryl halides to give the corresponding 2-alkyl (alkaryl) derivatives (118-g); and with chloroacetic acid ethyl chloroacetate to give compounds 111 and IV respectively further reaction of IV with ammonia and amines yielded 5-cyano-2(glycolamidethio)-6-phenyl pyrimidine-4(3H) one derivatives (Va-g). The parent thiazolo[3,2-a]pyrimidine (VI) was prepared from compound 111 by refluxing with acetic anhydride. Also compound I reacted with hydrazine hydrate to give 2-hydrazino derivative IX was converted into a variety of triazolo(4.3-a] pyrimidine derivatives. The biological activity of the new compounds was tested as microbicidal and bioregulator agents, the results obtained were correlated with their structure.

SYNTHESIS AND REACTIONS OF SOME NEW 5-CARBONYL(4-AMINO-3-CYANO-2-SUBSTITUTED THIOPHENE-5-YL)-8-HYDROXYQUINOLINE (PART II). SYNTHESIS OF THIAZOLE; ISOXAZOLE; PYRAZOLE, PYRIMIDINE AND PYRIDAZINE DERIVATIVES AS POSSIBLE ANTIMICROBIAL AGENTS

Abstract 5-Carbonyl-(3,4-diamino-2-ethylcarboxylatethieno[2,3-b]thiophene-5yl)-8-hydroxyquino-line (1) reacts with various reagents to afford thiazole, oxadiazole, pyrazole, isoxazole, pyrimidine and pyridazine derivatives (2–13d). The structure of the compounds has been established by elemental analysis. IR, NMR and mass spectra. The compounds thus synthesized were screened for their antimicrobial activity.

SYNTHESIS AND REACTIONS OF SOME NEW 5-CARBONYL(4-AMINO-3-CYANO-2-SUBSTITUTED THIOPHENE-5-YL)-8-HYDROXY QUINOLINE AS POSSIBLE ANTIMICROBIAL AGENTS (PART I)

Abstract S-Alkylation of 5-carbonyl-(4-amino-3-cyanothiophene-2-thio-5-yl)-8-hydroxyquinoline (4) with several halogen- containing compounds afforded the alkylthio derivatives (5a-f). Treatment of 4 with chloramine gave isothiazolothiophene (7), which was allowed to react with diethylmalonate and/or ethylacetoacetate to give the corresponding pyrimidinoisothiazolothiophenes (8) and (9). Ring closure of 5d-f with ethanolic sodium ethoxide gave thieno[2,3-b]thiophene derivatives (6a-c). Acetic anhydride, ammonium acetate, phenylisothiocyanate, nitrous acid, acetylacetone, phosphorus oxychloride, phosphorus pentachloride, hydrazine hydrate and benzoyl chloride gave further cyclization to construct an additional ring. The structure of the compounds has been established by elemental analysis, IR, NMR and mass spectra. The compounds thus synthesized were screened for their antimicrobial activity.