Abstract
withZ˭O Y˭C10, OC5, and Z˭S, Y˭C5, C10, OC5 OC12 were prepared by esterification of the α- keto acid with the appropriate phenol or thiol using the carbodiimide method. Mesomorphic properties were determined by hot-stage polarizing microscopy. The trend of a preference for a smectic A phase observed earlier in the analogous esters with Y˭C9CO was also observed in these esters/thioesters. As expected, transition temperatures were higher than the analogous esters with a C10, chain on the acid side.
The α-keto acid was synthesized by a Friedel-Crafts acylation of bromobenzene, protection of the α-keto group, conversion to the nitrile and hydrolysis of the nitrile and ketal groups. A new synthesis of a 4-alkoxybenzene thiol via sulfonation of an alkoxybenzene with CISO3H followed by reduction is also reported.