[Process monitoring the synthesis of N-dichloroacetyloxazolidine by thin-layer chromatography]

A thin-layer chromatographic procedure has been developed for the monitoring and identification of the synthesis of N-dichloroacetyloxazolidine by dichloroacetyl chloride, an alcoholamine and a ketone. The determination of reaction was made on the plates at room temperature. The reaction liquid was spotted on the silica gel G thin-layer plate and developed using solvent system, dichloromethane-methanol(10:1, V/V), until the solvent front migrated 10 cm from the starting spot. Then, the separated spots(raw materials and product) were scanned in iodine. About 1 hour, the raw material spots disappeared gradually and the product spots became clear, then the reaction had basically completed. Compounds A, B, C and D had Rf values of 0.71, 0.76, 0.75 and 0.79 respectively. The repeatability of Rf value was good. The TLC procedure has also been developed for the identification of the recrystallization of crude product. After recrystallization, there was one spot on the plate. Then, the products were confirmed by IR, 1HNMR and elemental analysis. The separation conditions were easily obtained. This method is simple, rapid, sensitive and reproducible.