Evelin B. Moawad

Convergent synthesis and antibacterial activity of pyrazole and pyrazoline derivatives of diazepam.

Polysubstituted pyrazoles (5)(a-l), pyrazolines (7)(a-c), (8)(a-c) and pyrazolotriazine (10) derivatives of diazepam were synthesized. The structures of hitherto unknown compounds were established by analytical and spectral methods. Some of these compounds were screened to test their antibacterial activity against gram-positive (B. subtilis) and gram-negative (P. aeruginosa). All compounds showed potent activity against these bacteria.

The Evaluation of Some Heterocycles as Antioxidant Additives for Lubricating Oils

Abstract 2-Phenyl-4-thienylidene-2-oxazolin-5-one I was prepared and reacted with 2-aminothiazole, p-aminophenol, and p-aminoacetophenone in the presence of acetic acid containing catalytic amounts of freshly fused sodium acetate to give the corresponding imidazolone derivatives II, III, and IV, respectively. A Claisen reaction of IV with ethylacetate gave the corresponding imidazolone V, which on reaction with phenylhydrazine in ethanol afforded the corresponding pyrazolinoimidazolone VI. On the other hand, I reacted with o- and p-phenylenediamines in ethanol and yielded the corresponding o- and p-aminophenylcarboxamide of α-phenyl carboxamido-β-thiophenoacrylic acids VII and VIII, respectively. The prepared products were evaluated as antioxidant additives for Egyptian lube oils. Some of these products showed good results.

Synthesis and evaluation of some new oxazolones and imidazolones as antioxidant additives for Egyptian lubricating oils

Oxazolone derivative 2 was utilized as a key intermediate for synthesis of some new oxazolone and imidazolone derivatives. Reaction of oxazolone derivative 2 with diamines under different conditions afforded the corresponding imidazolone derivatives 3–8, respectively. Moreover, oxazolone 2 reacted with some heterocyclic amines in glacial acetic acid giving the corresponding imidazolone derivatives 9–14, respectively. Cyclocondensation of thiosemicarbazide with compound 2 in dry pyridine afforded compound 15. Addition of secondary amines to olefin double bond of compound 2 gave the corresponding addition products 16–19, respectively. Michael addition of compound 2 with some active methylene compounds afforded oxazolone derivatives 20–23, respectively. These prepared products were evaluated as antioxidant and corrosion inhibitors for gasoline lubricating oil and compounds 6a–c, 10 and 15 exhibited the highest antioxidant and anticorrosive activities. The effect of concentration of additives was studied to recommend the optimum concentration to be used. The results showed, for additive 15, 0.1 g for 1 L oil was the more effective concentration. Measurements for thermal analysis and of surface tension of oil after oxidation were also carried out.

The Synthesis and Evaluation of Some New Multifunction Additives for Egyptian Gasoline Motor Oils

Abstract 2-[2-(1,3-Diphenyl-1H-pyrazol-4-yl)-vinyl]-benzo[d][1,3]oxazin-4-one (2) was utilized as a key intermediate for the synthesis of some new quinazolinone derivatives incorporating diphenylpyrazole moiety. Treatment of benzoxazine derivative 2 with different amines, namely, p-phenylenediamine, p-anisidine, p-toluidine, sodiumazide, hydroxylamine hydrochloride, phenyl hydrazine, and hydrazine hydrate afforded pyrazolyl quinazoline derivatives 3, 4, 5, 6, 7, 9, and 10, respectively. Structure 10 was undergoing acetylation and benzoylation with acetic anhydride or benzoyl chloride to afford 11 and 12, respectively. Representative compounds of the synthesized products were established and evaluated as antioxidant and corrosion inhibitors for gasoline lube oils.

Synthesis of Some Novel Antioxidant and Anticorrosive Additives for Egyptian Lubricating Oils

Abstract The starting oxazolone 1 was reacted with p-aminophenol in glacial acetic acid to afford imidazolone 2, which afforded Mannich base 3 via the reaction with piperidine and paraformaldehyde. Moreover, the reaction of 2 with ethylchloroacetate or chloroacetic acid in dry acetone gave the corresponding imidazolones 4 and 5, respectively. Compound 4 reacted with benzylamine or 4-chlorobenzaldehyde to furnish 6 and 7, respectively. On the other hand, oxazolone 1 reacted with hydrazines in glacial acetic acid to afford the 1,2,4-triazines 11–15. Representative compounds of the synthesized products were established and evaluated as antioxidant and corrosion inhibitors for gasoline lube oils.

Synthesis, characterization and antibacterial activity of some new thiazole and thiazolidinone derivatives containing phenyl benzoate moiety

Abstract 4-Formylphenyl benzoate was utilized as a versatile precursor for the construction of new series of heterocyclic scaffolds that contain thiazole and thiazolidin-5-one rings. The antibacterial activity of these scaffolds against two types of bacteria was screened and most of them exhibited good activity. Among the synthesized thiazole derivatives, compounds 5, 6, and 8a showed antibacterial activity close to the standard chemotherapeutic (Ampicillin). Graphical Abstract