The present invention relates to novel N-(3-((diethylamino)methyl)-4-hydroxyphenyl)-N-(quinolin-4-yl)sulfonamide derivatives, their preparation, to pharmaceutical compositions comprising them, and to their use as therapeutic agents, particularly in the prevention or treatment of tuberculosis. The present invention particularly relates to compounds of formula A: Formula A wherein: R = methyl, (or) R = a group of the structure wherein, R1, R2, and R3 may be same or different present at any positions) and are groups selected from the group consisting of hydrogen, halogen, alkyl (C1-C3), nitro, cyano, trifluoromethyl, (or) R is a group of the structure wherein X may be CH or N, and the attachment point of sulfonyl may be at the position 1 or 2, (or) R is a group of the structure Where R1 is hydrogen or halogen, (or) R is a group of the structure
