Nazmi Abdel Latif Kassab

Reactions with 1(2H)-phthalazinones, 4,5-dihydro-3(2H)-pyridazinones and 3-pyrazolin-5-ones

Abstract The condensation of 1(2H)-phthalazinones (Ia-c), 4,5-dihydro-6-phenyl-3(2H)-pyridazinone (IIIa), and 4-arylidene-4,5-dihydro-6-phenylpyridazinones (IVa-b) with secondary amines and formaldehyde yields the corresponding N-Mannich-bases (Id, IIIc-d, and IVi-j, respectively). Similarly, reaction with acrylonitrile, affords the cyanoethylated products (Ig, IIIf, and IVk-1, respectively). The Mannich-bases (Id) are also obtained by reaction of the appropriate amines with the corresponding chloromethyl- (If), or hydroxymethylphthalazinone derivatives (Ie); and by treatment of the hydroxymethyl derivative of IIIa with the same reagents. In the presence of ethyl-amine, the condensation of la-c with formaldehyde yields the corresponding bis-derivatives (II). The reaction of 3-methyl-2-phenyl-3-pyrazolin-5-one (Va) with formaldehyde and piperidine or morpholine involves the hydrogen atom on C 4 with formation of the Mannich-bases (Vd-e). In addition, the synthesis of some of the corresponding bis-derivati es (VI) are reported. The IR spectra of the reaction products are discussed. Interaction of Vd with aromatic thiols leads to the formation of 4-arylthiomethyl-3-methyl-2-phenyl-3-pyrozolin-5-ones (IVf-i). The latter compounds react with ethereal diazomethane yielding products believed to have structures similar to VII. Treatment of 2-N-piperidinomethyl-4-phenyl-1(2H)-phthalazinone (cf. Id), and 2-N-piperidino-methyl-6-phenyl-4,5-dihydro-3(2H)-pyridazinone (IIIe) with phenylmagnesium bromide, followed by hydrolysis, gives 1,4-diphenylphthalazine and 3,6-diphenylpyridazine (VIII), respectively. The latter has also been obtained by the action of the same reagent on IIIa and/or 6-phenyl-3(2H)-pyridazinone.

Cleavage reactions with 4-substituted isoxazolin-5-ones

Abstract The exocyclic double bond in 4-arylidene-3-methylisoxazolin-5-ones (IV) undergoes addition reactions with Grignard reagents and with aromatic hydrocarbons in the presence of aluminium chloride. The behaviour of the hetero-ring in 4-substituted 3-methylisoxazolin-5-ones towards the action of hydrazines has been investigated. Whereas, the corresponding pyrazolines (X) are obtained in the case of hydrazine hydrate, the intermediate hydrazides (XI) have been successfully isolated in the case of phenylhydrazine. The hydrazides are readily cyclized under different experimental conditions to yield different products.

Reactions with 4-substituted isoxazolin-5-ones—II☆

Abstract The exocyclic double bond in 4-arylidene-3-substituted-isoxazolin-5-one (I) undergoes addition reactions with Grignard reagents and with benzene in the presence of aluminium chloride. Treatment of 4-arylazo derivatives of 3-substituted-isoxazolin-5-ones (III) with Grignard reagents does not effect hetero-ring opening and only the carbonyl group of III enters into reaction, followed by elimination of the elements of water on acidifcation, yielding 3-substituted-4-arylazo-5-arylisoxazoles (IV). Deacylation of 4-acetyl-3-phenylisoxazoline-5-one (VI) is achieved by the action of organomagnesium compounds, magnesium-magnesium iodide mixture, and/or lithium aluminium hydride. 3,4-Disubstituted-5-methoxyisoxazoles (X) are readily obtained upon treatment of II with diazomethane. 2-Methyl-3,4-disubstituted-isoxazolin-5-one (XI) are produced via the action of methyl iodide on the silver salt of II and/or via the action of dimethyl sulphate on IIa directly.

Cleavage Reactions of Oxazolin-5-ones Reactions with 4-Substituted-2-aryl-2-oxazolin-5-ones

Abstract The oxazoline ring in 4-arylazo-2-aryl-2-oxazolin-5-ones (1) is converted to triazolyl-carbonyl amino acids 2, 4 and 6 by the nucleophiles glycine, anthranilic and p-aminobenzoic acids, respectively. The arylidene derivatives 3 of 2-triazolyl-2-oxazolin-5-one were obtained. Triazolylbenzoxazinones 5, were obtained by the ring closure of the amino acid 4. Grignards reagent effected ring cleavage of the oxazolinone ring in 4-cinnamylidene-2-aryl-2-oxazolin-5-ones yielding the carbinols 8, the latter cyclizes either in acidic or alkaline medium to afford either benzotropilidenes or oxazolines, respectively.

Arylazoisoxazolinthiones: Preparation and Reactions of 4-Arylazo-3-methyl-2-isoxazolin-5-thiones

Abstract The arylazo derivatives (2) of 3-methyl-2-isoxazolin-5-thione were prepared. Alkylation of 2 with alkyl halides results in the formation of the S-alkyl derivatives (5). The S-acetate esters undergo thermal isomerisation to the corresponding 1,2,3-triazole derivatives (6). The thiones 2 condense with hydrazines and primary amines to afford the corresponding 5-hydrazones and 5-imines (8) and (10), respectively. Treatment of 2 with hydrazine hydrate and Phenylhydrazine in boiling alcohol effects ring cleavage with the formation of 9.

CCDC 890175: Experimental Crystal Structure Determination

Related Article: Fathy M. Abdelrazek, Nadia H. Metwally, Nazmi A. Kassab, Mohammed T. Jaafar, Peter Metz, Anne Jager|2014|J.Heterocycl.Chem.|51|1785|doi:10.1002/jhet.1883