Crystal structure of (.+-.)-trans-2-cyclobutylamino-5,6-dihydroxy-1,2,3,4-tetrahydro-1-naphthalenol hydrobromide.

Abstract

The crystal structure of (±)-trans-2-cyclobutylamino-5, 6-dihydroxy-1, 2, 3, 4-tetrahydro-1-naphthalenol hydrobromide, a potent β-adrenergic stimulant, has been determined by X-ray diffraction techniques. The compound crystallizes from water in the triclinic space group P1 with a=9.198 (1), b=10.472 (2), c=8.020 (1) A, α=109.09 (2), β=78.20 (1), γ=102.55 (2)°. The structure was solved by the heavy atom method, and the final R for 1300 independent reflections measured with a four circle diffractometer was 5.0%. The cyclohexene moiety of the compound is in a half-chair conformation, with both the benzylic hydroxyl and the substituted amino groups occupying diequatorial positions. Comparison of the crystal structure with that of dl-isoproterenol sulfate shows that both compounds have similar conformations of the aliphatic side chain moiety, including the alkyl amino side chain.