Sayed A. Shiba

Synthesis and Antifungal Activity of Some New Quinazoline and Benzoxazinone Derivatives

The hitherto unknown 2‐isopropyl‐6,8‐dibromo‐4H‐3,1‐benzoxazin‐4‐one (2) was subjected to condensation with either primary or secondary amines affording the benzamide derivatives (3—7), while with alcohols in presence of the base, corresponding esters were obtained (8 and 9). Acylation of the hydrazide (12) or its cyclized form (13) gave (14—17). The quinazolinone derivative (18) was obtained either when (12) was reacted with nitrous acid or via fusion of (2) with ammonium acetate. The thione (20) which was obtained via reaction of (18) with Lawessons reagent, was subjected to either alkylation yielding (21—25) or desulphurization with primary amines affording (26 and 27). Treatment of (18) as well as (20) with a chlorinating agent provided (29, 30) and (28, 29) mixtures, respectively. Ten of our compounds were examined against Sclerotium cepivorum as well as Botrytis allii on PDA media. These compounds showed a significant reduction of mycelial growth and scleratia number of these fungi which cause the white rot and neck rot diseases of onion.

Utility of cyano- N -(2-oxo-1,2-dihydroindol-3-ylidene)acetohydrazide in the synthesis of novel heterocycles

Cyano-N-(2-oxo-1,2-dihydroindol-3-ylidene)acetohydrazide was prepared by condensation of isatin with cyanoaceto-hydrazide in refluxing 1,4-dioxane. Subsequent reaction with a variety of electrophilic and nucleophilic reagents afforded novel heterocyclic compounds and spirooxoindoles. The IR, 1H NMR and mass spectra of all the synthesised compounds are discussed.

N- vs. S-PTC Alkylation of 5-Carboethoxy-2-thiouracil And Its Reactivity Towards Some Nucleophilic Reagents

The reactivity of 5-carboethoxy-2-thiouracil (1) toward alkylation by different organohalogen compounds under phase-transfer catalysis (PTC) conditions has been investigated to give S-monoalkylated products and/or simultaneous S- and N-dialkylated products. Also, nucleophilic additions of methylmagnesium iodide, hydroxylamine, and hydrazine to 5-carbethoxy-2-thiouracil (1) have been investigated. The structures of all products have been confirmed by elemental analysis and spectral data.

SYNTHESIS AND INSECTICIDAL ACTIVITY OF NOVEL ACRYLONITRILE DERIVATIVES

Abstract (E)-3-p-Anisyl-2-cyano-2-propenoyl chloride and/or azide (1b and c) underwent successful nucleopbilic displacement reactions, with urea and thiourea derivatives to give the mono- or di- displacement products (4, 8, 2 and 5) respectively, beside other cyclic products (3 and 6); with aromatic binucleophilies e.g. o-phenylene diamine, the expected di-displacement products (12 and 13) were obtained, while with 2-aminophenol a mixture of two mono-displacement products (15 and 16) were isolated.

Uses of piperonal in the synthesis of novel prop-2-enoyl amides, esters, heterocyclic systems and study of their antibacterial activities

Novel (E)-3-(benzo[d][1,3]dioxol-5-yl)-2-cyanoacryloyl chloride 4 was condensed with several mono-; 1,2-; 1,3- and 1,4-bi-nucleophilic reagents containing nitrogen and oxygen to give new 2-propenoylamide and ester derivatives. Some of these amides cyclised under the reaction conditions and/or with POCl3 to give new derivatives of heterocyclic systems. Antibacterial activities were tested for nine of these products.

Decomposition of 2-propenoyl azide derivatives. Synthesis and larvicidal activity of novel products

Decomposition of 2‐propenoyl azide (1c) with nitrogen, oxygen, and sulfur nucleophiles affords the azido displacement products. Ring closure of some of these products produces the heterocyclic systems pyrimidone (3), oxadiazine (6), oxadiazole (8), benzimidazole (10), benzothiazole (12), and benzoxazinone (14). The larvicidal activity of some of these products against Culex pipiens was evaluated.

N-VS. O-(S-) PTC ALKYLATION OF 3-CYANO-4,6-DIMETHYL-2-OXO (THIOXO)-1,2-DIHYDROPYRIDINE

Abstract N-Alkylation versus O-/or S- alkylation reactivity of 3-cyano-4,6-dimethyl-2-oxo(thi-oxo)-1,2-dihydropyridine have been investigated under phase transfer catalysis conditions.

PTC-ALKYLATION AND MICHAEL ADDITION OF INDANONES; SYNTHESIS OF 2-SUBSTITUTED INDANONES

Abstract The reactivity of indan-1-one (1a) and or indan-1,3-dione (1b) towards alkylation in the absence or presence of carbon disulphide under phase transfer catalysis (PTC) conditions has been investigated to give indanone derivatives 2–9. Michael addition of (1a,b) to α,β-unsaturated carbonyl compounds under the same FTC conditions yielded the adducts 10–16.

The Utility of p-N-Succinimidobenzoyl Isothiocyanate in Synthesis of Benzoxazole, Quinazoline, Pyrimidine, 1,2,4-Triazoline, 1,3-Thiazolidine, and Thiourea Derivatives

Reactions of p-N-succinimidobenzoyl isothiocyanate (1) with different nucleophilic reagents afforded adducts. Simultaneous or subsequent cyclization of these adducts gave access to a variety of different heterocycles, including benzoxazole, quinazoline, pyrimidine, 1,2,4-triazoline, 1,3-thiazolidine and others. The structures of the new products were confirmed by their micro-analytical and spectral data. Supplemental materials are available for this article. Go to the publishers online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

SYNTHESIS OF SOME BIOLOGICALLY ACTIVE HETEROCYCLES. REACTIONS OF THE HYDRAZIDE OF 2′-THIENOYL ANTHRANILIC ACID AND ITS 3,5-DIBROMO DERIVATIVE

Abstract The hydrazide of 2′-thienoyl anthranilic acid and its 3,5-dibromo derivative (1a and b) were condensed with carbon disulphide to give 1–3′-quinazolin-2-thione 5–2′′-aminophenyl-1,3,4-triazoles (2a, b). When treated with acetyl chloride 3-N-acetamidoquinazolin-4-ones (3a, b), with aromatic aldehydes the schiff bases 4 and 5(a, b). Potassium thiocyanate and phenyl isothiocyanate gave the semicarbazide derivatives (6a, b) while ammonium thiocyanate afforded the triazol-thiones (7a, b). Reaction with ethyl acetoacetate and acetylacetone gave the pyrazole derivatives 8 and 9 respectively; Biological activities of some of these compounds are tested.