Many Eucalyptus waxes contain as major components long-chain β-diketones, which may be readily separated from the rest of the wax as insoluble copper complexes. The most commonly occurring β-diketone is n-tritriacontan-16,18-dione, but in two species, Eucalyptus risdoni and E. coccifera, β-diketones of shorter chain length predominate. From the waxes of several Eucalyptus species a new flavone, 5-hydroxy- 4',7-dimethoxy-6,8-dimethylflavone, and a new triterpene, 11,l2-dehydroursolic lactone acetate, have been isolated. Gas chromatography has been used to determine the chain length distribution of β-diketones, hydrocarbons, and esters from several waxes. The esterified alcohols of Eucalyptus globulus and E. risdoni belong to two series-long-chain n-alkan-1-ols of predominantly even carbon number, and n-alkan-2-ols of medium chain length and predominantly uneven carbon number (n-C9, n-C11, n-C13, and n-C15).

The insect moulting hormone crustecdysone has been isolated from the Australian brown pine, Podocarpus elatus R.Br., and detected in a number of other Podocarpus species from various parts of the world. A series of acetates and acetonides of crustecdysone has been prepared, and the mass and nuclear magnetic resonance spectra of these compounds analysed. A simple micro method of measuring the rate of acetylation of hydroxy groups in steroids has been developed to determine the steric environment of these groups.

The cuticle wax of the grape is composed of a soft wax (30%) readily removed by light petroleum and a hard wax (30%), mainly oleanolic acid, removed by chloroform. The soft wax of the fresh grape is composed chiefly of long-chain alcohols together with smaller amounts of aldehydes, esters, fatty acids, hydrocarbons, oleanolic acid, and small amounts of high molecular weight substances. The soft wax of dried grapes is similar in composition but contains no aldehydes and larger amounts of high molecular weight substances and oxidation products. The aldehydes, unusual wax components, are straight chain and range from C16 to C32 with the even chain-lengths predominating. They were destroyed by neutral alumina but can be chromatographed on silicic acid.

The structure assigned to the liquid nematocidal principle of Tagetes roots 5-(3-buten-1-ynyl)-2,2'-bithienyl (II), by Uhlenbroek and Bijloo, has been confirmed by studying the mass spectra and nuclear magnetic resonance spectra of (II) and its hydrogenation products. α-Terthienyl (I) and (II) have also been isolated from fresh roots of T. minuta (T. glandulifera).

From an examination of the nuclear magnetic resonance spectra, optical rotations, and other properties of a number of flavonoid C-glycosides, their acetates, and related model compounds, it is concluded that vitexin, bayin, puerarin, and isohemiphloin are C-P-D-glucosides with the sugar substituent in the 8-position of the flavonoid nucleus. Hemiphloin and saponaretin are two of the corresponding 6-substituted compounds. In hemiphloin and isohemiphloin the phenyl B ring has the equatorial configuration.Although C-glycosylflavonoids or glycoflavonoids occur widely in nature, progress with the elucidation of their structures has been slow and few have been completely worked out. These substances yield very small amounts of sugar when hydrolysed or degraded with ozone. Consequently the nature of the sugar moiety and its location have been largely deduced indirectly; and conclusions have been dependent on several uncertainties, such as isomerization, which can occur during examination of these relatively unstable compounds. Accordingly, a nuclear magnetic resonance study has been made of a number of these substances and related model compounds to provide more direct information about the structures of this class of compound, and in particular, the compounds hemiphloin and isohemiphloin discussed in an earlier communication.1Since this work was started, several spectral correlations of other flavonoid classes have been p u b l i~h e d ,~-~ and demonstrate the value of this technique. Recently the chemistry of most of the compoimds studied (Table 1) has been reviewed,B and the structures of vitexin and i~o v i t e x i n ,~ and orientin and homo-orienting have been related by means of n.m.r. spectroscopy.