| 摘要 |
NEW MATERIAL:The compound of formula I (A is -N=CH-; R is alkyl) or formula II. EXAMPLE:2-(4-Octanoyloxybenzylidenamino)phenanthrene. USE:A raw material of liquid crystal display element. It exhibits nematic liquid crystal phase in a relatively high temperature range, and is most suitable as a liquid crystal display element for high-temperature use or its constituent component. It can be used in the liquid crystal display element singly or as a mixture of two or more kinds of the compounds. Any of the titled compounds can be used in combination with other compounds exhibiting nematic liquid crystal phase. PREPARATION:The compound of e.g. formula IV can be prepared by (1) reducing phenanthrene of formula III with a copper chromate catalyst, (2) nitrating the obtained compound of formula VI with fuming nitric acid in glacial acetic, (3) dehydrogenating the product, (4) reducing the resultant compound of formula VIII, and (5) carrying out the dehydrative condensation of the product with 4-acyloxybenzaldehyde.
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