title: Organic crystal engineering with 1,4-piperazine-2,5-diones. 6. Studies of the hydrogen-bond association of cyclo[(2-methylamino-4,7-dimethoxyindan-2-carboxylic acid)(2-amino-4,7-dimethoxyindan-2-carboxylic acid)].
abstract: [structure: see text] The title 1,4-piperazine-2,5-dione was synthesized in 23% yield over six steps from ethyl 2-amino-4,7-dimethoxyindan-2-carboxylate. Crystallization by slow diffusion of ether into a chloroform solution and by slow evaporation of an ethanol-chloroform-benzene solution produced polymorphic crystalline forms as determined by single-crystal X-ray analysis. The polymorphs exhibited different hydrogen-bonding networks. The association of this piperazinedione in solution was studied using mass spectrometric and nuclear magnetic resonance spectroscopic techniques. The MS and NMR data were interpreted using the solid-state structures as models for solution aggregation. Association constants extracted from the NMR data are in line with those of other cyclic cis amides in chloroform solvent.
authors.affiliation: Department of Chemistry, University of Arizona, Tucson, 85721-0041, USA.
authors.forename: Robin A
authors.initials: RA
authors.lastname: Weatherhead-Kloster
authors.forename: Hugh D
authors.initials: HD
authors.lastname: Selby
authors.forename: Walter B
authors.initials: WB
authors.lastname: Miller Iii
authors.forename: Eugene A
authors.initials: EA
authors.lastname: Mash
mesh_terms: D002264:Carboxylic Acids / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D019281:Dimerization; D006860:Hydrogen Bonding; D007189:Indans / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D010879:Piperazines / Q000737:chemistry*; D011522:Protons; D021241:Spectrometry, Mass, Electrospray Ionization; D013696:Temperature
chemical_list: D002264:Carboxylic Acids; D007189:Indans; D010879:Piperazines; D011522:Protons; C510881:cyclo((2-methylamino-4,7-dimethoxyindan-2-carboxylic acid)(2-amino-4,7-dimethoxyindan-2-carboxylic acid))