Synthesis, spectral analysis and antibacterial activity of some novel 5-substituted-2-((6-bromo-3,4-methylenedioxybenzyl)thio)-1,3,4-oxadiazole derivatives.

A number of novel 5-substituted-2-((6-bromo-3,4-methylenedioxybenzyl)thio)-1,3,4-Oxadiazole derivatives (6a-l) have been synthesized to evaluate their antibacterial activity. Using aryl/aralkyl carboxylic acids (1a-l) as precursors, 5-substituted-1,3,4-Oxadiazol-2-thiols (4a-l) were yielded in good amounts. The derivatives, 4a-l, were subjected to electrophilic substitution reaction on stirring with 6-bromo-3,4-methylenedioxybenzyl chloride (5) in DMF to synthesize the required compounds. All the synthesized molecules were well characterized by IR, 1H-NMR, 13C-NMR and EIMS spectral data and evaluated for antibacterial activity against some bacterial strains of Gram-bacteria. The molecule, 6d, demonstrated the best activity among all the synthesized molecules exhibiting weak to moderate inhibition potential.

Report: Synthesis and screening of some new N-alkyl/aralkyl-N-(3,4- ethylenedioxybenzyl)-4-substituted benzenesulfonamides as potential antibacterial agents.

The various p-substituted benzenesulfonyl chlorides (2a-e) were treated with (3,4-methylenedioxy) benzylamine (1) in the presence of aqueous Na2CO3 solution to synthesize N-(3,4-methylenedioxybenzyl)-4-substitutedbenzenesulfonamides (3a-e). The synthesized molecules were further converted into corresponding N-ethyl/benzyl/4-flourobenzyl-N-(3,4-methylenedioxybenzyl)-4-substitutedbenzenesulfonamides (7a-e, 8a-e, 9a-e) on reaction with ethyl iodide (4), benzyl chloride (5) and 4-flourobenzyl chloride (6) in the presence of sodium hydride using N,N-dimethylformamide as solvent. The structure elucidation was processed through different spectral techniques including IR, 1H-NMR and EIMS. The screening of the synthesized molecules against Gram-bacterial strains, to evaluate antibacterial activity, showed them moderately good inhibitors as shown by their low MIC values.

Synthesis and antibacterial screening of S-substituted derivatives of 5-(3,4-methylenedioxyphenyl)-1,3,4-oxadiazol-2-thiol.

The most emerging class among the heterocyclic compounds is 1,3,4-oxadiazoles for their diverse biological activities. In the present research work, piperonylic acid (1) was converted consecutively into corresponding ester (2), hydrazide (3) and 1,3,4-oxadiazole (4) through intermolecular cyclization. The synthesized compound 4 was subjected further to S-alkylation/aralkylation, using alkyl/aralkyl halides (5a-m) and S-substituted-1,3,4-oxadiazole derivatives were synthesized (6a-m). The structure elucidation of the synthesized molecules was processed through (1)H-NMR, IR and mass spectral data. The antibacterial activity showed these molecules moderately good inhibitors of gram-negative and gram-positive bacteria.

N-(3-Eth-oxy-phen-yl)-4-methyl-benzene-sulfonamide.

In the title compound, C(15)H(17)NO(3)S, the two aromatic rings make a dihedral angle of 69.42 (9)° with each other and the bridging C-N-S-C torsion angle is 65.76 (16)°. Weak intra-molecular C-H⋯O inter-actions may affect the mol-ecular conformation. Two neighbouring mol-ecules generate a hydrogen-bonded dimer about a center of inversion through a pair of inter-molecular N-H⋯O inter-actions, forming an R(2) (2)(8) ring motif. Furthermore, two inter-molecular C-H⋯π inter-actions contribute to the stability of the crystal packing.