摘要:
The antibiotic nitrofurantoin {systematic name: (E)-1-[(5-nitro-2-furyl)methylideneamino]imidazolidine-2,4-dione} is not only used for the treatment of urinary tract infections, but also illegally applied as an animal food additive. Since derivatives of 2,6-diaminopyridine might serve as artificial receptors for its recognition, we crystallized one potential drug-receptor complex, nitrofurantoin-2,6-diacetamidopyridine (1/1), C8H6N4O5 center dot C9H11N3O2, (I center dot II). It is characterized by one N-H...N and two N-H...O hydrogen bonds and confirms a previous NMR study. During the crystallization screening, several new pseudopolymorphs of both components were obtained, namely a nitrofurantoin dimethyl sulfoxide monosolvate, C8H6N4O5 center dot C2H6OS, (Ia), a nitrofurantoin dimethyl sulfoxide hemisolvate, C8H6N4O5 center dot 0.5C(2)H(6)OS, (Ib), two nitrofurantoin dimethylacetamide monosolvates, C8H6N4O5 center dot C4H9NO, (Ic) and (Id), and a nitrofurantoin dimethylacetamide disolvate, C8H6N4O5 center dot 2C(4)H(9)NO, (Ie), as well as a 2,6-diacetamidopyridine dimethylformamide monosolvate, C9H11N3O2 center dot C3H7NO, (IIa). Of these, (Ia), (Ic) and (Id) were formed during cocrystallization attempts with 1-(4-fluorophenyl)biguanide hydrochloride. Obviously nitrofurantoin prefers the higher-energy conformation in the crystal structures, which all exhibit N-H...O and C-H...O hydrogen-bond interactions. The latter are especially important for the crystal packing. 2,6-Diacetamidopyridine shows some conformational flexibility depending on the hydrogen-bond pattern.