Aromatic wing

Bent-core mesogens are a very special type of mesogen and possess quite distinct properties from the known rod-shaped mesogens. Compared to a rod-shaped LC molecule including one rigid aromatic core and two flexible tails, a bent-core molecule consists of one central bent unit (BU), two rod-like aromatic wings (RWs), and two flexible tails (Fig. 6.2). Hence, bent-core molecules are also called banana or bow-shaped molecules due to their distinct bent shape (Fig. 6.1c). It is known that rod-shaped molecules can rotate freely around their long molecular axes. In contrast. 

Several investigators have studied the reaction betwn Phenylhydrazine and various aromatic aliphatic compds. The fo do wing Refs should be of interest... 

Male moths and butterflies have proven to be an especially rich source of interesting natural products. The sex pheromone produced in the wing glands of the lesser waxmoth, Achroia grisella, is composed of n-undecanal and (Zj-ll-octadecenal (98), whereas that of the greater waxmoth also contains n-undecanal (.99) but is dominated by n-nonanal (100). The scent brushes of male noctuid moths produce large amounts of aromatic compounds and terpenes which are believed to function as aphrodisiacs (101). Benzaldehyde, 2-phenyl ethanol, benzyl alcohol, 6-methyl-5-hepten-2-one, pinocarvone, and isobutyric acid have been identified in the secretions of different noctuid species (102), and it appears that these pheromones may possess some chemotaxonomic value. 

Many of the beautiful colors of butterflies wings, autumn leaves, and flowers are due to the presence of flavone derivatives called anthocyanins. When antho-cyanins are hydrolyzed in hydrochloric acid (to remove sugar residues), they produce aromatic oxygen-containing salts. One of these is delphinidin chloride. Explain why delphinidin chloride is aromatic. What is the hybridization of the heterocyclic oxygen in this compound ... 

C21H26N4O6, Mr 430.46, yellow powder. P. II is a pigment in the wings of the swallowtail butterfly Papilio xuthus and other Papilio species, it is composed of l- kynurenine, noradrenaline, and /S-alanine. The yellow color is due to a charge-transfer interaction between the two aromatic rings. 

Fig. 9.30 Illustration of the chiral propeller-like conformation produced by the twisting of ester linkage between two aromatic rings in bent core and side wing...

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