Iron chelators of the pyridoxal-based class. Part 7. The synthesis and single crystal structure of 1-(N-ethoxycarbonylmethylpyridoxyledenium)-2-(pyrimidyl)hydrazine salts

The syntheses of 1-pyridoxylidene-2-(2'-pyrimidyl)hydrazine (1), 1-(N-methy lpyridoxylideniun)-2-(2'-pyrimidyl)hydrazine iodide (2), and 1-(N-ethoxycar bonyl methylpyridoxylidenium)-2-(pyrimidyl)hydrazine bromide (5a),and 1-(N- ethoxycarbonylmethylpyridoxylidenium)-2-(2'-pyrimidyl)hydrazine perchlorate (5b) are described. The single-crystal structure of 5b was determined from three-dimensional X-Ray data. Compound (5b), C16H22N5O8Cl, crystallizes in the space group P2(1)/c with Z = 4 and the following cell dimensions : a = 12.363 (3) Angstrom, b = 17.168(5) Angstrom, c = 9.657(3) Angstrom. The X- Ray data confirm that 5b crystallizes in the di-polar form, as a planar 20- membered ring dimer {preferred motif of R-2(20)}. All the three proton-dono rs (O-1-H, O-2-H, and N-3-H), and only three (N-2, N-5, O-2) of the five av ailable proton-accepters 5b, are utilized in hydrogen-bonding.