ABSOLUTE-CONFIGURATION OF (+)-ETHAMBUTOL HYDROBROMIDE

(S,S)-N,N'-Bis(1-hydroxymethylpropyl)ethylenediammonium bromide, C10H26N2O2(2+). 2Br-, M(r) = 366.1, orthorhombic, P2(1)2(1)2, a = 23.045 (4), b = 6.735 (1), c = 5.291 (6) angstrom, V = 821.2 angstrom 3, Z = 2, D(x) = 1.4 g cm-3, lambda(Mo K-alpha) = 0.71069 angstrom, mu = 48.8 cm-1, F(000) = 372, T = 293 K, final R = 0.037 for 986 observed reflections. The cations, which are protonated at N, lie across crystallographic twofold rotation axes. In the crystal the Br anions are hydrogen bonded to the H(N) groups of two different cations and to the H(O) group of a third cation. The absolute configuration of the (+)-ethambutol cations is S,S.