Methyl 3α,6α-diacetoxy-10-oxo-(7α)-kemp-11-en-20-oate: The revised structure for the kempane derivative from the frontal gland secretion of Nasutitermes costalis soldiers

The structure of methyl 3α,6α-diacetoxy-10-oxo-(7α)-kemp-11-en-20-oate (II) was established by X-ray analysis for a defense compound of termites Nasutitermes costalis. The previously suggested structure I with 7β-kempane skeleton is revised.

Minor diterpene components of the defense secretion from the frontal gland of soldiers of the species Nasutitermes costalis (HOLMGREN)

Three minor components of the defense secretion from soldiers of the species Nasutermes costalis (HOLMGREN) have been isolated and characterized by means of spectral methods. The first component was identified as 1(15),8(19)-trinervitadien-9β-ol (III), known to occur with the subfamily Nasutitermitinae. For the second component two alternative structures IVa, IVb have been tentatively suggested, both with the 7,16-secotrinervitane skeleton. The third component was determined as 5β,9β-diacetoxy-2-oxo-11(12)kempen-20-oic acid (VII). The kempene skeleton was established on the basis of the 13C NMR spectrum and mass spectral fragmentation of the acid methyl ester. The relative configuration, together with a probable conformation of the tetracyclic framework were determined by 1H NMR. Two major tricyclic components, 1(15),8(19)-trinervitadien-2α,3β-diol (I) and 1(15),8(19)-trinervitadien-2α,3α-diol (II), were further characterized as mono and diacetates. Different rates of acetylation of the hydroxy groups in these diols provided evidence of stable conformation of the six-membered ring within the trinervitane skeleton.

TERMITE DAMAGE AND CONTROL AS FACTORS IN THE UTILIZATION OF TIMBER IN THE CARIBBEAN AREA

The destructiveness of termites presents a challenge to everyone connected with forestry and wood utilization in the Tropics, as well as to the consuming public. On the basis of biological differences and methods of control, the West Indian species divide into three groups: The "nigger-head" nest termites, of which Nasutitermes costalis Holmgren is typical and most common, but commercially least injurious; the subterranean termites, of which Heterotermes tenuis Hagen is most destructive; and the dry-wood termite, Cryptotermes brevis Walker. Some of the new insecticides, more especially those developed by Julius Hyman, such as Chlordan, Aldrin, Dieldrin, and others, are exceptionally effective in killing termites, and the impregnation of susceptible woods with pentachlorphenol or sodium pentachlorphenate prevents attack so long as this thin surface protection is unbroken. But as all North American woods except the gummy heartwood of bald cypress and Osage orange are susceptible to termite attack, the foresters of the Caribbean area have a unique opportunity in pushing the commercial planting of endemic termite- resistant woods such as West Indian mahogany, Demerara greenheart, and others less well-known, as well as East Indian teak.