Studies in Sulphonamides-Part XII
Defence Science Journal
Four new 1 , 3-diarylpropawd, 3-diones, 1-(mlp-nitropheny1)-3-(p-ethylpheny1)-and 1-(mlp-nitropheny1)-3-(p-ethoxyphenyl)-propane-1, 3-diones have been synthesised and coupled w~th a number of diazotised sul-pho&e bases to yield the corresponding 1, 3-diaryl-2-(N-substituterl p-sulphamylbenzeneazo) propane-1, 3-diones. These azo-compounds have been screened in vitro for their antibacterizl propertie-, againqt S. aureur, E. coli and P. pyocyanea. In earlier papers the effect of chloro, bromo,
... chloro, bromo, methyl and mzhoxyl groups and the effect of exchanging the nitro group from meta to para positions when present in the phsnyl rings of propane-1, 3-dionss has been describedl'2. As an extension of this work, the pressnt comrnunicatio.z d:als with the synthe;is . of four new 8-diketones. With a view to compare ths rates of coupling rezctions, t h w /I-diketon: w:re inade to react with differently substituted diazotised sulphonarnide bases to give the corresponding 1,3diaryl-2-(N-substituted-p6tf~amylkienzeneazo) propane-1, 3-diones. These azo-compounds here later subjected to in vitro screening against three micro-organisms. During the course of thi; work it has observed that the rate of coupling reaction increased wh:n ths ethyl group present in the phenyl ring at the position-3 of the propane-1, 3-dione was rzplaced by aa ethoxyl group thereby giving higher yields. The other observation was that the, shifting of the nitro group from meta to the para position in the phenyl ring attached at position-1 of the propane-l,3-dione caused an overall increase in the .yields of the azo-compounds. The yields of the azo-compounds ranged between 71 to 85 %. E X P E R I M E N T A L P R O C E D U R E The following four new /3-diketones were prepared by employing th.: standard method3. 1-(m-Nitropheny1)-3-(p-ethylphenyl) propane-1, 3-dione . in-Nitrobenzaldehyde (0.06 mol) and p-ethylacetophenone (0.06 rnol) wcre condensed in presence of aqueous sodium hydroxide to give rn-nitrobenzylidene p-ethylacetophenone which was crystallised from ethanol as a light yellow solid, m. p. 120' . 4 (Found : C, 72.6; H, 5.4. Cl,H~ii 0 3N requires C, 72.8; H, 5.3 %). This styryl ketone on bromination gave the dibromide, map. 120°, subsequent dehydrobromination and hydrolysis yielded 1-(m-nitropheny1)-3-(p-ethylphenyl) propane-1, Zdione, which on crystallisation from ethanol-glacial acetic acid mixture in light yellow needles had m.p. 127' .