(S)-Spiro[(1,3-diazacyclopent-1-ene)-5,2‘-(7‘-methyl-1‘,2‘,3‘,4‘- tetrahydronaphthalene)]:  Resolution, Stereospecific Synthesis, and Preliminary Pharmacological Characterization as a Partial α-Adrenergic Agonist

Recently, we reported on the design, synthesis, and structure−activity relationships of a series of spiroimidazolines endowed with α-adrenergic agonist activities. Among the compounds described, (R,S)-spiro(1,3-diazacyclopent-1-ene)-[5,2‘](7‘-methyl-1‘,2‘,3‘,4‘-tetrahydronaphthalene) fumarate (<BO>5</BO><BI>RS</BI>) was chosen for further development as a venotonic agent. The resolution of this compound, as well as the pharmacological characterization of the enantiomers, stereospecific synthesis of eutomer (<BO>5</BO><BI>S</BI>, S 18149), and determination of absolute configuration by single-crystal X-ray diffraction analysis, are described.