Synthesis and characterization of new gallic acid derivatives complimented with antibacterial activity

This work consists of synthesis of new oxazepine and diazepine compounds according to the Schemes shown below.

In order to obtain the target compounds, the following routes were adopted:-

• Preparation of  3,4,5-tripropoxy benzoic acid (II) by the reaction of gallic acid (I) with propylbromide.
• Preparationofmethyl-3,4,5-tripropoxybenzoate(III) via direct esterfication of compound (II) with methanol in presence of sulfuric acid as catalyst.
• Preparation of 3,4,5-tripropoxybenzoic hydrazide (IV) from the reaction of ester compound (III) with hydrazine hydrate.
• The reaction of hydrazide compound (IV) with carbon disulfide in basic media leads to the formation of thio carbazinate salts (V) which undergoes cyclization in excess of hydrazine hydrate to give 3-thio-{5-yl-(3`,4`,5`-tripropoxyphenyl)}-4-amino-1,2,4-triazole (VI).
• Shiff`s bases (VII)_a-j were synthesized through the condensation reaction of  3-thio-{5-yl-(3`,4`,5`-tripropoxyphenyl)}-4-amino-1,2,4-triazole (VI) with different aromatic aldehydes in absolute ethanol and in presence of few drops of glacial acetic acid.
• 1,3-Oxazepine-4,7-dione derivative compounds (VIII)<sub>a-j</sub> were synthesized by the reaction of Schiff`sbase compounds (VII)_a-j with phthalic anhydride in dry benzene.
• [1,3] diazepine (IX)_a-j was prepared by the reaction of schiff`s bases (VII)_a-j with isatin in ethanol.