SHORT COMMUNICATIONSIn continuation of our previous studies [1-3] on the chemical behavior of 1,3-dehydroadamantane (I) toward carbonyl compounds, we examined its reactions with bicyclic ketones: 1,7,7-trimethylbicyclo[2.2.1]-heptan-2-one (II, DL-camphor) and 5,5,6-trimethylbicyclo[2.2.1]heptan-2-one (VI, isocamphanone). The reaction mixtures were analyzed by gas chromatography-mass spectrometry. The reaction of 1,3-dehydroadamantane (I) with camphor (II) gave approximately equal amounts of two stereoisomeric addition products at the C 3 atom of II (endo-III, exo-III; m/z 286 [M] + ); the chromatogram contained two peaks with close retention times and identical mass spectra. In addition, 1,1′-biadamantane (IV, m/z 270 [M] + ) and camphor dimer (V, m/z 301 [M] + ) were identified as by-products.In the reaction of 1,3-dehydroadamantane (I) with isocamphanone (VI) the major product (yield ~80%) was compound VIIb formed as a result of addition of I at the C 3 atom of VI. Also, addition product VIIa at the C 1 tertiary carbon atom (m/z 286 [M] + , ~5%), 1,1-biadamantane (IV, recombination product of 1-adamantyl radicals), and isocamphanone dimer VIII were formed.Thus, high reactivity of 1,3-dehydroadamantane ensures formation of addition products with trimethylbicyclo[2.2.1]heptan-2-one derivatives in one step with high yields under fairly mild conditions. Possible biological activity of some adducts was analyzed using Mikrokosm software. It was found that compounds III and VIIb may be interesting as potential drugs [4] possessing analgesic, narcotic, and cardiotonic activity.