SYNTHESIS AND HPLC-SEPARATION OF CHIRAL 1,3,4-THIADIAZINES AND 1,3,4-SELENADIAZINES

The reaction of 4-isopropylthiosemicarbazide and 4-alkyl(aryl)-2-methy lthiosemicarbazides and -selenosemicarbazides, respectively, with alph a-halogenketones yields 1,3,4-thiadiazines and 1,3,4-selenadiazines. I n the presence of acids or bases the title compounds undergo ring cont raction eliminating sulphur and selenium, respectively, and formating pyrazoles. This paper reports on the HPLC-investigation of chiral 1,3, 4-thiadiazines and 1,3,3-selenadiazines on different chiral stationary phases. The influence of pH-value, charged and uncharged modifiers in the mobile phase on the chromatographic resolution are discussed.