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SUMMARY The bicyclic conjugated sesquiterpene ketone, nootkatone, has been found in grapefruit peel oil and in peel‐oil‐free grapefruit juice. The flavor intensity of grapefruit oil appears to be related to the relative abundance of nootkatone. A combination of gas‐liquid chromatography and thin‐layer chromatography revealed the presence of this ketone, which was identified by its infrared spectrum and the melting point of its 2,4‐dinitrophenylhydrazone derivative. Traces of nootkatone were found also in bergamot, lemon, lime, orange, and tangerine oils.

protons, confirming its total reduction. Chromatography on alumina still did not permit crystallization, so the material was acetylated with pyridine and acetic anhydride. Prisms of racemic 0,N-diacetyldemethyldihydrogalanthamine were obtained which were recrystallized from ethyl acetate and sublimed at 150" (0.1 mm.), m.p. 208-209.5", [ o l I z 3~ 0.00,' [alZ3436 0.00' ( c 0.19, chloroform). The infrared spectrum in chloroform was identical with its optically active counterpart (m.p. 177-179'). Surprisingly, the compound does not appear t o depress the racemic 0,s-diacetyldemethylgalanthamine, m.p. 204-205', b u t fortunately its infrared spectrum ( K B r ) exhibits many points of difference.Conversion of Dihydronarcissamine to Racemic Dihydrogalanthamine.--4 solution of 150 mg. of the crude hydrogenation product of narcissamine in a mixture of 1 ml. of 9076 formic acid and 1 ml. of 3 i y G formalin was heated on the steam bath for 3 hr., basified, and extracted into chloroform. The product was then chromatographed over alumina with 1 YG ethanol in ethyl acetate and the resulting oil evaporatively distilled a t 150' (0.1 m m i . The infrared spectrum of the product is identical in chloroform solution with ( -)-dihydrogalanthamine and gas phase chromatography shows a retention time identical with the latter (see above). The material was purified by crystallizing its hydriodide salt from water, recovering the free base with alkali, and evaporatively distilling the product. Still an oil, the product showed [ a I z 3 D 0.0", [olIz3496 0.0" ( c 0.655, chloroform).Anal. Calcd. for C l i H~N 0 3 : C , 70.56; H , 8.01. Found: C, 70.32; H, 7.91.The compound formed a methiodide from acetone which was recrystallized from ethanol-water; m.p. 300' dec. The infrared spectrum ( K B r ) of the salt is very similar to, but not identical with, t h a t of ( -)-dihydrogalanthamine methiodide.(+)-Camphor was converted to (-))-homocamphor by known methods and in a short synthetic sequence the latter was transformed to the tricyclic cyclopentenone 10. Condensation with methylmagnesium iodide or with triphenylphosphinemethylene followed by hydrogenation yielded 8-patchoulene ( 12). Rearrangement of the corresponding epoxide 16 with boron fluoride furnished the desired unsaturated alcohol 18. This key intermediate was subsequently transformed to patchoulione ( 2 ) and to a-patchoulene (23). ' % previously accomplished b u t at t h a t time incorrectly interpreted reconversion of ol-patchoulene (23) to patchouli alcohol ( 2 8 ) completed the synthesis. Some transformations of the natural product 28 are reinterpreted in terms of a new structure determined by the X-ray method.

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