CRYSTAL AND MOLECULAR-STRUCTURES OF THE FREE-BASE AND THE MONOHYDROCHLORIDE SALT OF THE ANTILEUKEMIC AGENT GLYOXAL BIS(AMIDINOHYDRAZONE) [GLYOXAL BIS(GUANYLHYDRAZONE)]
N. Mutikainen et al., CRYSTAL AND MOLECULAR-STRUCTURES OF THE FREE-BASE AND THE MONOHYDROCHLORIDE SALT OF THE ANTILEUKEMIC AGENT GLYOXAL BIS(AMIDINOHYDRAZONE) [GLYOXAL BIS(GUANYLHYDRAZONE)], Zeitschrift fur Naturforschung. B, A journal of chemical sciences, 48(12), 1993, pp. 1821-1827
The first study on the crystal and molecular structures of basic forms
of bis(amidinohydrazones) is reported. The structures of the free bas
e and the monohydrochloride salt of the antileukemic agent glyoxal bis
(amidinohydrazone) (GBG) were determined by single crystal X-ray diffr
action and were refined to R-values of 0.038 and 0.040, respectively T
hese structures are of special interest because recent results indicat
e that, in contrast to previous assumptions, the free base may be the
actual antileukemic form of bis(amidinohydrazones) and that the monoca
tion form is the predominant species of antileukemic bis(amidinohydraz
ones) at physiological conditions. In the crystals of the free base as
well as in those of the monohydrochloride salt, GBG was found to exis
t solely in the all-trans configuration of the chain and to consist of
one of the three possible geometrical isomers only. In the solid stat
e, GBG free base consists solely of the endiamine tautomer instead of
the 'classical' carboximidamide tautomer, as does also the non-protona
ted part of GBG monocation in the monohydrochloride salt. Proton NMR m
easurements indicated that the free base consists of the endiamine tau
tomer also in dimethyl sulfoxide solution. In the solid state, both of
the compounds studied consist of stacks of planes. In the case of the
free base, the stacks are crisscross to each other. The distance betw
een the mean planes of the molecules or the monocations is approximate
ly 3.5 Angstrom. The crystals of the monohydrochloride salt contain on
e molecule of water per each GBG monocation. In both compounds studied
, the molecules in the crystals are held together by very extensive hy
drogen bond networks and by the interaction of delocalized pi-electron
s. The crystal of C4H10N8 is monoclinic, space group C2/c with a = 15.
874(6), b = 6.972(4), c = 7.813(5) Angstrom, beta = 90.34(4)degrees an
d Z = 4. The crystal of C4H13N8OCl is monoclinic, space group P2(1)/n
with a = 7.010(3), b = 22.307(9), c = 7.028(3) Angstrom, beta = 66.33(
3)degrees and Z = 4.