Synthesis and mesophase behavior of several cholesteryl esters

Starting from the corresponding carboxylic acids,via esterification under the catalysis of DCC and DMAP,four cholesteryl esters were obtained,namely multisubstituted cholesteryl benzonates 4-CnH2n+1O-3,5-(Br)2-C6H2-COOCh,(n=5,7,9)5,6,7 and 4-biphenyl-4-yl-4-oxo-butyric acid cholesteryl ester 9.By investigation of DSC and polarized microscope,5,6,7 show narrow cholesteric mesophase,and are considered to belong to cholesteric liquid crystals.9 is a new compond showing no liquid crystalline behavior.