Abstract:
This project focusses on the synthesis of novel 6,8-disubstituted-chromone-3-carboxamides
and their evaluation as potential anti-tuberculosis agents.
In this study, four 3-iodo-5-substituted-2-hydroxyacetophenones (58A-D) and three 3-bromo-
5-substituted-2-hydroxyacetophenones (63A-C) were successfully synthesized from 5-
substituted-2-hydroxyacetophenones (57A-D). The Vilsmeier-Haack reaction was used to
synthesize the 8-iodo-6-substituted-chromone-3-carbaldehydes and 8-bromo-6-substitutedchromone-
3-carbaldehydes from the 3-iodo/bromo-5-substituted-2-hydroxyacetophenones.
These compounds were treated with sodium chlorite and sulfamic acid to afford corresponding
chromone-3-carboxylic acids.
Recrystallization with either ethanol or methanol was used to purify the synthesized
compounds. All compounds were synthesized in good to excellent yields. The yields of the 3-
iodo-5-substituted-2-hydroxyacetophenones (58A-D) ranged from 55 - 75 %, the 3-bromo-5-
substituted-2-hydroxyacetophenones (63A-C) were synthesized with yields from 66 - 87 %,
the percentage yields are significantly different probably because different methods were used.
The yields of the 8-iodo-6-substituted-chromone-3-carbadehydes (59A-D) ranged from 78 –
90 %, the 8-bromo-6-substituted-chromone-3-carbaldehydes (64A-C) with yields from 85 - 87
%, 8-bromo-6-substuted-chromone-3-carboxylic acids from 47 – 52 %, and chromone-3-
carboxylic acid afforded a yield of 57 %.
1H NMR, 13C NMR and FTIR spectroscopic techniques were used to characterize synthesized
compounds and also confirmed by melting points for compounds reported in literature.
