Crystal structures and supra-molecular features of 9,9-dimethyl-3,7-di-aza-bicyclo-[3.3.1]nonane-2,4,6,8-tetra-one, 3,7-di-aza-spiro-[bi-cyclo-[3.3.1]nonane-9,1'-cyclo-penta-ne]-2,4,6,8-tetra-one and 9-methyl-9-phenyl-3,7-di-aza-bicyclo-[3.3.1]nonane-2,4,6,8-tetra-one di-methyl-formamide monosolvate.

ABSTRACT: Compounds (I), C₉H₁₀N₂O₄, (II), C₁₁H₁₂N₂O₄, and (III), C₁₄H₁₂N₂O₄·C₃H₇NO represent 9,9-disubstituted-3,7-di-aza-bicyclo-[3.3.1]nonane-2,4,6,8-tetra-one deriv-atives with very similar mol-ecular geometries for the bicyclic framework: the dihedral angle between the planes of the imide groups is 74.87?(6), 73.86?(3) and 74.83?(6)° in (I)-(III), respectively. The dimethyl derivative (I) is positioned on a crystallographic twofold axis and its overall geometry deviates only slightly from idealized C_2v symmetry. The spiro-cyclo-pentane derivative (II) and the phen-yl/methyl analog (III) retain only inter-nal C_s symmetry, which in the case of (II) coincides with crystallographic mirror symmetry. The cyclo-pentane moiety in (II) adopts an envelope conformation, with the spiro C atom deviating from the mean plane of the rest of the ring by 0.548?(2)?Å. In compound (III), an N-H?O hydrogen bond is formed with the di-methyl-formamide solvent mol-ecule. In the crystal, both (I) and (II) form similar zigzag hydrogen-bonded ribbons through double inter-molecular N-H?O hydrogen bonds. However, whereas in (I) the ribbons are formed by two trans-arranged O=C-N-H amide fragments, the amide fragments are cis-positioned in (II). The formation of ribbons in (III) is apparently disrupted by participation of one of its N-H groups in hydrogen bonding with the solvent mol-ecule. As a result, the mol-ecules of (III) form zigzag chains rather than the ribbons through inter-molecular N-H?O hydrogen bonds. The crystal of (I) was a pseudo-merohedral twin.

SUBMITTER: Vatsadze SZ 

PROVIDER: S-EPMC5499299 | biostudies-literature | 2017 Jul

REPOSITORIES: biostudies-literature