Anne-Charlotte Wiehager

The crystal structure of chanootin, a bicyclic C15-tropolone

Chanootin, C15H~803, is a bicyclic C15-tropolone isolated from the heartwood of Chamaecyparis nootkatensis (Lamb.) Spach. (Cupressales, Cupressaceae). From o.r.d, data the compound appears to be optically inactive although it contains asymmetric carbon atoms. Chanootin crystallizes in space group P2,/c, with Z=4, a=9-158, b=8.372, c= 18.627/1,, t = 112.26o; i.e. it must exist as a racemate. Threedimensional intensity data were recorded with an automatic diffractometer and scintillation counter. The structure was determined by the application of direct methods and refined by full-matrix leastsquares calculations to a final R index of 0.049. The carbon-carbon bond lengths of the tropolone ring exhibit bond alternation, as reported for tropone derivatives and the ring is only approximately a planar heptagon.