Alyaa A. Shalaby

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.

A New Approach for the Synthesis of Some Fused Pyrazolo-, Triazolo-, Tetrazolo-, Diazepino-, Oxazepino-, and Thiazepinopyridazine Derivatives

Hydrazinolysis of 4-benzoyl-5,6-diphenyl-pyridazin-3(2H)-one 1a in acetic acid or 3-chloropyridazine derivative 2 in ethanol afforded the pyrazolo[3,4-c]pyridazine derivative 3 . While boiling 1a with hydrazine hydrate in ethanol gave the corresponding hydrazono derivative 4 . Reaction of compound 2 with benzhydrazide in refluxing 1-butanol yielded triazolo[4,3-b]pyridazine 5 . On treatment of 2 with sodium azide tetrazolopyridazine 6 resulted. The reaction of 1a (in acetic acid) or 2 (in ethanol) with o -phenylenediamine and o -aminophenol yielded diazepino- and oxazepinopyridazine derivatives 7a and 7b , respectively, while 2 with o -aminothiophenol in ethanol gave thiazepinopyridazine derivative 7c . Moreover, treatment of 1a (in acetic acid) or 2 (in ethanol) with ethylenediamine and 2-aminoethanol produced 8a , 8b and 9a , 9b respectively. Chlorination of the carbinol derivatives 11a and 11b with phosphorus oxychloride gave the dichloro derivatives 12a and 12b , which reacted with hydrazine to form pyrazolopyridazines 13a and 13b respectively. However, thionation of 11b gave the thionated product 14 . Compound 14 was confirmed by methylation and hydrazinolysis forming 15 and 16 respectively.

NOVEL METHODS FOR THE SYNTHESIS OF SOME PYRIDAZINO-, FURO-, AND POLYSUBSTITUTED PYRIDAZINES

ABSTRACT 3,4-Diethoxycarbonyl-5,6-diphenylpyridazine 1 reacted with hydrazine hydrate to form tetrahydropyridazino [4,5-c]pyridazine 2, which reacted with ethyl bromoacetate to give 6,7-diethoxycarbonylmethyl-3,4-diphenyl-5,8-dioxopyridazino [4,5-c]pyridazine 3. However, acetylation of 2 with acetyl chloride gave three different pyridazino[4,5-c]pyridazines 4–6. The reaction of the starting diester 1 with different amounts of phenylmagnesium bromide gave different products 7–10. The structure of product 8 was elucidated by alkaline hydrolysis and hydrazinolysis to afford 11 and 13, respectively. Treatment of 13 with benzaldehyde in piperidine yielded the starting Grignard product 8 and benzalazine 17.

Synthesis of Heterobicyclic Nitrogen Compounds as Molluscicide Agents Derived from 6-Methyl-5-styryl-1,2,4-triazin-3-thiol: Part I

Some new heterocyclic nitrogen compounds 1-14 have been synthesized from cyclization of 5-styryl-3-mercapto-6-methyl-1,2,4-triazines 1 with active methylene and/or nitrogen compounds and were evaluated as molluscicidal agents. Significant molluscicidal activities for some of the products towards Biomophalaria Alexandrina snails were observed.

Synthesis and reactions of 3,4-dicarboxy-5,6-diphenylpyridazine

Abstract Diethyl acetylenedicarboxylate 2 reacted with benzilmonohydrazone 1 to form 3,4-dicarboxycarbony 1-5,6-diphenylpyridazine 3, which upon alkaline hydrolysis gave the corresponding dicarboxylic acid 4. Decarboxylation of 4 gave 3,4-diphenyl-pyridazine 7. On treatment of 4 with acetyl chloride or thionyl chloride, 3,4-diphenyl-5,7-dioxofuro[3,4-c]pyridazine 8 was formed. Friedel-Crafts acylation on 8 gave 4-benzoyl-3-carboxy-5,6-diphenylpyridazine 9, 3-benzoyl-4-carboxy-5,6-diphenyl-pyridazine 10 and 4-benzoyl-5,6-diphenylpyridazine 11. Hydrazinolyis of 9 and 10 produced the isomeric pyridazino[4,5-]pyridazines 15 and 16, respectively. Reaction of 5,7-di-oxofuro[3.4-c]pyridazine 8 with distilled aniline gave the unexpected product 3,4-diphenyl-5-(N-phenyl) formamidopyridazine 17.