2680-49-1Relevant academic research and scientific papers
SYNTHESIS AND MESOMORPHIC PROPERTIES OF THREE HOMOLOGOUS SERIES OF 4,4 prime -DIALKOXY- alpha , alpha prime -DIMETHYLBENZALAZINES.
Marcos,Melendez,Serrano
, p. 157 - 172 (2007/10/02)
Three homologous series of alpha , alpha prime -dimethylbenzalazines have been synthesized: 4,4 prime -dialkoxy- alpha , alpha prime -dimethylbenzalazines, 4,4 prime -dialkoxy-2,2 prime -dihydroxy- alpha , alpha prime -dimethylbenzalazines, and 4,4 prime -dialkoxy-2-hydroxy- alpha , alpha prime -dimethylbenzalazines. The influence of molecular structure on the mesomorphic properties was studied. Mesomorphic properties and phase transitions were determined using a polarizing hot-stage microscope and a differential scanning calorimeter. The introduction of one or two hydroxyl groups in position 2- or 2-and 2 prime -of the aromatic rings (4,4 prime -dialkoxy-2-hydroxy- alpha , alpha prime -dimethylbenzalazines and 4,4 prime -dialkoxy-2,2 prime -dihydroxy- alpha , alpha prime -dimethylbenzalazines respectively) gives molecules with an excellent mesogenic quality, and all the prepared compounds of these series exhibit mesomorphism. Compounds of the series with two hydroxyl groups exhibit smectic polymorphism which is not so in the case of the compounds of the other series. The melting temperatures are systematically lower for the 4,4 prime -dialkoxy-2-hydroxy- alpha , alpha prime -dimethylbenzalazines than for the other two series.
