Normal-and reversed-phase thin-layer chromatography of some 3-(2'- furoyl)-5-x-2,4-dioxotetrahydro-1,3-thiazole derivatives

Abstract

The chromatographic behavior of 3-(2'-furoyl)-5-X-2,4-dioxotetrahydro- 1,3-thiazole derivatives (X = H, benzylidene, 1'-naphthylidene, 2'-fluoro-6'- chlorobenzylidene, 3'4'-dimethoxybenzylidene, 4'-dimethylaminobenzylidene, 4'-isopropylbenzylidene, 2'-thienylidene, 5'-methyl-2'-furylidene) has been studied on thin-layers of silica gel, rice starch, and cellulose, and on HPTLC plates coated with LiChrospher Si60F(254s), using cc ammonia, cc ammonia-methanol (0.1-0.2), cc ammonia-dioxane (0.04-0.2), and cc ammonia- acetonitrile (0.02-0.14) as mobile phases. Normal-phase chromatography was observed on silica gel layers whereas reversed-phase chromatography was observed on rice starch and cellulose layers. Retention constants, R°(M), were determined by extrapolation. Results show that extrapolated R°(M) values are the same irrespective of whether the organic modifier of the mobile phase is methanol, dioxane, or acetonitrile. Very good correlation was obtained between experimental and extrapolated R°(M) values and good correlation was found between the intercepts and slopes of the TLC equations and the retention constants, R°(M), and log P. Results show that rice starch is a good RPTLC system and can be used for determination of the lipophilicity of the molecules investigated. The best separation of the investigated compounds was obtained on LiChrospher Si60F(254s) HPTLC plates with n-hexane- ethyl acetate, 40 + 10 (v/v), as mobile phase.