Certain varieties of teak cause marked skin irritation and eczema. Investigation of veneers made from such varieties of teak, which had caused skin complaints among many workers in a veneer factory, have now led to the isolation and determination of the constitution of the active principle. Small amounts of golden yellow crystals, which had deposited on the veneers, were purified (m.p. 56-58 "C) by recrystallisation and column chromatography on silica gel. The compound is volatile in steam and has the empirical formula Cl~H1402. Its ultraviolet and infrared spectra indicate a naphthaquinone.OH 0 OH 0 1 XI After chemical characterisation, its constitution was clearly ratified by synthesis. The naphthahydroquinone I was obtained by reacting 1,4-naphthahydroquinone and y,y-dimethylallyl alcohol together in dioxan with boron triiluoride as catalyst. After oxidation with silver oxide and purification by column chromatography, this yielded a quinone, which, judging by its melting point and mixed melting point determinations, colour reactions, ultraviolet and infrared spectra, was identical with the quinone from teak. Accordingly, the new quinone is y,y-dimethylallyl-1 ,Cnaphthaquinone (11).The toxic quinone can be quickly detected in a cold alcohol extract from teak shavings by the violet-blue colour it develops in the Craven test [I]. Received, September 24th. 1962 [Z 355/182 IE] [l] R. Craven, et al. [l] have succeeded in preparing XeF4by heating a mixture of xenon and fluorine at 40OoC. We too, have been occupied for some time with the fluorination of xenon and have prepared a xenon fluoride differing from that of the American authors. Although our investigations are not yet completed, a brief report on our findings is given. Commercial xenon ("nachgereinigt", i. e. extra-purified, as supplied by Linde; 99.9 % Xe, <0.1 % Kr, CO.01 % N2, <0.001 % 0 2 ) was mixed with carefully purified fluorine (prepared electrolytically) in a Xe : F2 proportion of 1 : 2 by volume in a sealed quartz vessel and subjected at room temperature to discharges from an induction coil. The electrodes were sealed into quartz fingers which were fused onto and projected into the vessel. After a short interval, a fall in pressure occurred; after several (up to 10) hours, it corresponded at maximum to a 50 % decrease in volume of the original quantity of gas. Simultaneously a colorless crystalline condensate was formed on a cold finger cooled with a solid carbon dioxidefmethanol mixture. This primary condensate is strongly "fluorine-active" and on exposure to air has a nauseating characteristically heavy odor; the analytical data show that its overall composition corresponds approximately to the empirical formula XeF2.On warming in vucuo this condensate sublimes at about 0 OC. Evidently partial decomposition occurs in the process, since only a fraction of the original amount can be subsequently condensed using solid carbon dioxide/methanol; furthermore, elemental xenon was detected. On cooling the bottom of the reaction vessel with solid C02 durin...
