Synthesis and anti-tubercular activity of Thienyl and Furanyl derivatives

Abstract

The synthesis and anti-tubercular activity of series of acyl hydrazonyl compounds, namely ( E )- N' -(arylidene)thiophen-2-carbohydrazide, ( E )- N' -(arylidene)furan-2-carbohydrazide, ( E )- N -methyl- N' -arylidene-thiophen-2-carbohydrazide, and E )- N -methyl- N' -arylidene-2-(thien-2yl)-acetohydrazide, [32 compounds in all] are reported. The activities of against Mycobacterium tuberculosis H37Rv (ATTC27294) are compared with those ( E )- N' -arylidene-2-(thien-2-yl)-acetohydrazide, previously reported. The most active compounds are (aryl = 5-nitrothien-2-yl), (aryl = 5-nitrofuran-2-yl) and (aryl = 5-nitrothien-2-yl). Moderate activity was displayed by (aryl = 5-nitrofuran-2-yl) and certain derivatives of series where aryl is pyridin-2-yl or an o -hydroxyphenyl derivative. Doubling of certain NMR signals of each compound in solution indicates that a mixture of conformers, Z C(O)NH / E (C=N) and E C(O)NH / E (C=N) about the C(O)-NH-N=C(H, aryl) fragment is present. In contrast, only one form for each compound is present in solution from the single set of NMR signals. It is suggested that this form in solution is the E C(O)NH / E (C=N) form. Only a single set of NMR signals are found for the N -methylated derivatives.