H. M. F. Madkour

Reactions of 5-(p-Anisyl)-2-methyl-7-(p-tolyl)-4H-pyrido[2,3-d][1,3]oxazin-4-one

5-(p-Anisyl)-2-methyl-7-(p-tolyl)-4H-pyrido[2,3-d][1,3]oxazin-4-one (III) was prepared. The reactivity of III towards nucleophilic reagents was investigated. 5-(p-Anisyl)-2-methyl-7-(p-tolyl)-4H-pyrido[2,3-d] pyrimidin-4-one(VI) was synthesised from III by the action of ammonium acetate and zinc chloride. The structure of VI was chemically confirmed by reactions with acetic anhydride, benzoyl chloride, chloroacetic acid, methyl iodide, dimethyl sulphate and ethyl bromoacetate. Compound (VI) reacted with secondary and primary amines under Mannich conditions to afford 5-(p-anisyl)-2-methyl-3-methylene substituted amino-7-(p-tolyl)- 4H-pyrido[2,3-d]pyrimidin-4-ones (XIV) and (XV), respectively. Thiation of VI gave the thione 5-(p-anisyl)-2-methyl-7-(p-tolyl)-4H-pyrido [2,3-d]pyrimidin-4-thione (XIX)

Synthesis and Fungicidal Activity of New Imidazoles from 2-(Chloromethyl)-1H-benzimidazole

A series of substituted 2-thiomethylbenzimidazoles 2–4, 2-phenoxy-methylbenzimidazoles 5 and 2-aminomethylbenzimidazoles 6 and 7 were synthesized by reactions of 2-chloromethylbenzimidazole 1 with dithiocarbamate, pyrimidine-2-thiones, phenol derivatives, as well as primary aromatic and heterocyclic amines, respectively. Most of the synthesized compounds were screened for their antifungal activity against B. sinerea, F. solani, R. solani, and fungi. Some of the tested compounds showed 100% inhibition for the fungal growth at concentration ranges of 200–1000 ppm.

A FACILE ONE-POT SYNTHESIS AND ANTIBACTERIAL ACTIVITY OF AZIRIDINES AND THIAZINES FROM 1,3-DIARYLPROP-2-ENONES

Abstract The title compounds 1a,b as examples for acyclic alkenones were utilized for the synthesis of some heterocycles namely, thiazines 2a,b and 3a-d, pyrimidines 4a,b. aziridines 7a,b. The unexpected tribromides 8a,b, obtained from bromination of 1a,b, were readily used to afford the pyrazoles 9a,b and isoxazoles 10 a,b. Biological screening of some selective synthesised compounds was determined in vitro using Gram-negative and Gram-positive bacterial strains.

Synthesis, Antibacterial, and Antiviral Evaluation of New Heterocycles Containing the Pyridine Moiety

A facile one‐pot four‐component reaction was utilized to construct 2‐oxo‐1,2‐dihydropyridine‐3‐carbonitrile as a scaffold for the synthesis of many fused heterocyclic systems, namely, furopyridine, pyridothiadiazepinthione, and pyridotriazine, as well as non‐fused heterocyclic systems such as phthalazin‐2(1H)‐ylnicotinonitrile, pyridin‐2‐yl‐1H‐pyrazole, and pyrazol‐1‐ylnicotino‐nitrile,1‐(3‐cyanopyridin‐2‐yl)‐1H‐pyrazole. The new compounds were evaluated as antimicrobial and antiviral agents.

Synthetic Utility of Enaminonitrile Moiety in Heterocyclic Synthesis: Synthesis of Some New Thienopyrimidines

The hitherto unknown 3-amino-5-bromo-4, 6-dimethylthieno [2, 3-b] pyridine-2-carbonitrile ( 4 ) was condensed with p-anisaldehyde affording the Schiff base ( 5 ). Acylation of the thienopyridine derivative ( 4 ) using freshly distilled acetic anhydride gave a mixture of mono and diacetyl derivatives ( 6 ) and ( 7 ). Condensation of ( 4 ) with triethylorthoformate yielded the ethoxymethyleneamino derivative ( 8 ), which was treated with hydrazine hydrate to give the hydrazide derivative ( 9 ), which in turn was converted to a triazolopyrimidine derivative ( 10 ) upon treatment with freshly distilled acetic anhydride. Thiation of ( 4 ) with carbon disulfide afforded the pyrimidine dithione derivative ( 11 ), which was alkylated with ethyl iodide to give the di-s-ethylpyrimidine derivative ( 12 ).On the other hand, treatment of ( 4 ) with formamide yielded the aminopyrimidine derivative ( 13 ), whereas its treatment by formic acid produced the thienopyrimidinone derivative (1 4 ). Chlorination of (1 4 ) with a mixture of phosphorus pentachloride and phosphorus oxychloride gave the chloropyrimidine derivative ( 15 ), which in turn afforded the hydrazide derivative ( 9 ) upon treatment with hydrazine hydrate. Hydrazinolysis of ethyl-3-amino-5-bromo-4,6-dimethylthieno[2,3-b]pyridine-2-carboxylate ( 17 ) gave the hydrazino derivative ( 18 ), which in turn was converted to 8-bromo-7,9-dimethyl-3-formylaminopyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-4(3H)-one ( 19 ) and 8-bromo-3-diacetylamino-2,7,9-trimethylpyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-4(3H)-one ( 20 ) upon treatment with formic acid and freshly distilled acetic anhydride, respectively.

Synthesis and reactions of some 3-cyano-4-methylcoumarins

o-Hydroxy ketones (I) were converted into 3-cyano-4-methylcoumarins (II) via condensation with ethyl cyanoacetate in presence of piperidine or ammonium acetate as a catalyst. The behavior of compound (II) towards Grignard and Michael reactions was investigated. The reactions of 3-acetylcoumarin (III) with hydrazines under different conditions were carried out to give the hydrazone (IV a), phenylhydrazone (IV b) and pyrazole (V) derivatives. Also, the 4-styryl derivatives (VI) were obtained by condensation of II with different aromatic and heterocyclic aldehydes. A one pot synthesis of Michael product (VII) from the reaction of VI with malononitrile was described

The Utility of 2-(5,6,7,8-Tetrahydrobenzo[b]thieno-[2,3-d]pyrimidin-4-yloxy) Acethydrazide in Heterocyclic Synthesis

Because of being a versatile synthon, the title compound 2 was utilized to construct different heterocyclic systems including pyrazol-4-carbonitrile 3, pyrazolone 4, triazole-5(4H)-thione 7, aminotriazole 9, oxadiazoles 10 and 12, thiazolidine 13, and oxatriazole 14. All new synthesized compounds were structurally confirmed by elemental analyses and spectroscopic data.

Antioxidant Activity of Novel Fused Heterocyclic Compounds Derived from Tetrahydropyrimidine Derivative

6-(Benzo[d][1,3]dioxol-5-yl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitrile has been utilized for synthesis of the fused heterocyclic compounds namely thiazolopyrimidines, tetrazolopyrimidine, pyrimidoquinazoline, pyrimidothiazolopyrimidine, pyrimidothiazolotriazine and pyrrolothiazolopyrimidine derivatives. The newly synthesized compounds were characterized by IR, (1)H-NMR, (13)C-NMR, and mass spectral data. Antioxidant activities of all synthesized compounds were investigated.

Pyrimidinthiones (Part I): Utility of 2-Thioxopyrimidin-6-(1H)ones as Ring Transformer in the Synthesis of Fused Bi- and Tri-Cyclic Heterocyclic Compounds and Their Potential Biological Activities

The pyrimidinethiones have wide biological and pharmaceutical activities, that have attracted considerable interest in recent years especially as antiviral inhibiting production of hepatitis B virus (HBV), and in vitro insulin-mimetic. Activity of the complexes of pyrimidinone derivatives evaluated from 50% inhibitory concentration promoted us to study the transformation of the 2-thioxopyrimidin-6(1H) ones to fused bi- and tri-cyclic heterocyclic compounds having the pyrimidine moieties and screening their biological activity. The reactivity of 2-mercapto-4-aryl-5-cyanopyrimidin-6(1H)ones (1) towards alkylation by different mono and bifunctional halo-organic compounds has been investigated to give S-monoalkylated products 2, 7 and 9; S- and N-dialkylated products 3, 13 and 14. Treatment of 1 and/or 2 with hydrazine hydrate as a nitrogen nucleophile have been investigated to give 4, treatment of 4 with CS2 and sodium nitrite in the presence of acetic acid (0°C) produced 1,2,4-triazolopyrimidin-5(1H)one derivatives (5)and tetrazolo[1,5-a]pyrimidin-5(1H)ones (6), respectively. Also cyclization of 7 and 9 gave [1,3]thiazolo[3,2-a]pyrimidin-5(1H)one and [1,3]thiazolo[3,2-a]pyrimidin-3,5-dione derivatives 8 and 10 respectively, treatment of 10 with aromatic aldehyde produces 11 which reacted with guanidine HCl to give pyrimido[4,5-d]thiazolo[3,2-a]pyrimidin-6(1H)one derivative 12. Reaction of 14 with o-phenylenediamine was investigated and gave [1,4]quinoxalino[2,3-b][1,3]thiazolo[3,2-a]pyrimidin-9(1H)one derivative 15.

SYNTHESIS AND NUCLEOPHILIC REACTIONS OF N-(1-NAPHTHYL)- 3,4-METHYLENEDIOXYBENZYL-IDINEHOMOPHTHALISOIMIDIUM PERCHLORATE

ABSTRACT N-(1-Naphthyl)-3,4-methylenedioxybenzylidinehomophthalisoimidium perchlorate 6 was obtained via treatment of N-(1-naphthyl)-3,4-methylenedioxybenzylidine homophthalamic acid 5 with perchloric acid in acetic anhydride. The behaviour of 6 towards active methylene-containing compounds, Grignard reagents and aromatic primary amines and hydrocarbons, has been investigated.