NOVEL 9,9-DIOL SYSTEMS STARTING FROM A 3,7- DIAZABICYCLO[3.3.1]NONAN-9-ONE NUCLEUS-SINGLE CRYSTAL X-RAY DIFFRACTION ANALYSIS OF 3-(2-PROPYL)-7-BENZYL-3,7-DIAZABICY CL0[3.3.1]NONAN-9,9-DIOL HYDROBROMIDE, 3-(2-PROPY L)-7-[3,4-DIMETHOXYBENZYL)-3,7-DIAZABICY CLO[3.3.1]NONAN-9,9-DIOL HYDROBROMIDE, AND 3,7-DIISOPROPYL-3,7-DIAZABICY CLO[3.3.1]NONAN-9,9-DIOL DIHYDROCHLORIDE

Attempts to make inorganic metal complexes of 3,7-diazabicyclo[3.3.1]nonan-9-ones and metal bromides in fresh, reagent-grade, undried THF generated rare 9.9-diols. Treatment of the ketones with anhydrous HBr (g) in anhydrous ether gave hydrobromides with the proton on nitrogen and with the carbonyl group intact. The hydrobromides were extremely hygroscopic and exhibited a strong propensity to form the corresponding 9.9-diol system. The mechanism of formation of the diols is discussed as well as a rationale for the stability of such diols via H-bonding in the solid state. The X-ray diffraction analyses of 3-(2-propyl)-7-benzy1-3,7-diazabicyclo[3.3.I]nonan-9,9-diol hydrobromide, 3-(2-propyl)-7-(3.4-dimethoxybenzyl)-3.7abicyclo[3.3.1]nonan-9,9-diol hydrobromide, and 3,7-diisopropyl-3.7-diazabicyclo[3.3.l]nonan-9,9-diol dihydrochloride revealed a proton on N(3) and all bicyclic systems as chair-chair conformations in the solid state. The dihydrochloride was, of course, also protonated on N(7). This is the first systematic study of this type of 9.9-diol of the 3.7-diazabicyclo[3.3.1]nonane system and the corresponding carbonyl-containing hydrobromides with the proton on a nitrogen atom [N(3)].