3,6-双取代哒嗪的合成和介晶性

哒嗪衍生物;3;6-双取代哒嗪的合成和介晶性

Synthesis and Mesomorphism of 3,6-Disubstituted Pyridazines

Eight 3-alkoxy-6-(4-cholesteryloxycarbonylphenyl) pyridazines containing a pyridazine ring, a benzene ring, a cholesteryl, an ester group and an alkoxyl group of different length were synthesized through the cross-coupling reaction of 3-chloro-6-alkoxypyridazines and p-cholesteryloxycarbonylphenylboronic acid in the presence of palladium catalyst. The reaction of 3,6-dichloropyridazine with the alcohol under phase transfer catalyst gives 3-chloro-6-alkoxypyridazine. Their mesomorphism was studied by differential scanning calorimetry. The results showed that seven compounds have mesomorphism. The length of the terminal chain could affect the phase transition and clearing point temperatures of the compounds, but it has little influence on the temperature range of mesomorphous phases.