A. H. Abd El Rahman

A new synthesis of oxadiazole, thiazolidinone, N-phthalimidoamino carbonyl and arylidene derivatives with potential antimicrobial activity.

Condensation of carbohydrazide derivatives Ia, b with dimethyl acetylenedicarboxylate and acetylenedicarboxylic acid yielded benzofuran derivatives II a‐d. Reaction of Ib with aromatic aldehydes formed products III a‐d. Treatment of compounds III a‐d with mercaptoacetic acid yielded the cyclocondensation products (IVa‐d). Phthalic anhydride reacted with compounds (Ia, b)to form products (Va, b). It has been found that both khellin and visnagin (VIa, b)react with aromatic aldehydes to give arylidene derivatives (VIIa‐e). Condensation of diphenyl nitrilamine with 2‐arylidene furochromones VII derivatives afforded cyclo‐adducts (VIII a‐i). The antibacterial activities of the selected compounds were tested against Staphylococcus aureus, B. subtilis, E. coli, Pseudomonas, Salmonella and Erwinia with good results.

SYNTHESIS AND ANTIMICROBIAL ACTIVITY OF SOME BENZOFURAN DERIVATIVES

The Friedel-Crafts acylation of 2,3-diphenyl-5-methylbenzofuran 1a with succinic anhydride gives beta-(2,3-diphenyl-5-methylbenzofuranoyl)propionic acid 1b. Acid 1b reacts with hydrazines yielding the corresponding tetrahydropyridazinones 2. 4,5-Dihydro-1,2-oxazin-6H-6-one 6 is formed by reaction of 1b with hydroxylamine hydrochloride. The reaction of the pyridazinone 2a with dialkyl sulfates, ethyl chloroacetate, Grignard reagents, amines in presence of formaldehyde (Mannich reaction), o-amino-phenol and thiourea has been investigated. The antimicrobial activities of compounds 1a-c, 2a-c, e, f, 4a, b and 5a, b as well as 7b are studied.

Mannich Reaction with 2,3-Bis-(o-methoxyphenyl)-6-benzofuranol.

Das Benzofuranol (I) kondensiert mit Formaldehyd (II) und sekundaren Aminen (III) zu den Mannich-Basen (IV).