2,2,2-Trifluoro-N-(1a,2,7,7a-tetrahydronaphtho[2,3-b]oxiren-3-yl)acetamide by X-ray powder diffraction

Improved performance of crystal structure solution from powder diffraction data through parameter tuning of a simulated annealing algorithm

Significant gains in the performance of the simulated annealing algorithm in theDASHsoftware package have been realized by using theiraceautomatic configuration tool to optimize the values of three key simulated annealing parameters. Specifically, the success rate in finding the global minimum in intensity χ2space is improved by up to an order of magnitude. The general applicability of these revised simulated annealing parameters is demonstrated using the crystal structure determinations of over 100 powder diffraction datasets.

Powder X-ray study of racemic (2RS,3RS)-5-amino-3-[4-(3-methoxyphenyl)piperazin-1-yl]-1,2,3,4-tetrahydronaphthalen-2-ol

The structure of the title benzovesamicol analogue, C(21)H(27)N(3)O(2), an important compound for the diagnosis of Alzheimer's disease, has been determined by X-ray powder diffraction. The title compound was firstly synthesized and characterized by spectroscopic methods (FT-IR, and (13)C and (1)H NMR). The compound is a racemic mixture of enantiomers which crystallizes in the monoclinic system in a centrosymmetric space group (P2(1)/c). Crystallography, in particular powder X-ray diffraction, was pivotal in revealing that the enantio-resolution did not succeed. The piperazine ring is in a chair conformation, while the cyclohexene ring assumes a half-chair conformation. The crystal packing is dominated by intermolecular O-H···N hydrogen bonding which links molecules along the c direction.

Powder X-ray study of racemic (2RS,3RS)-5-amino-3-(4-phenylpiperazin-1-yl)-1,2,3,4-tetrahydronaphthalen-2-ol

The title compound, C(20)H(25)N(3)O, an important precursor for the preparation of benzovesamicol analogues for the diagnosis of Alzheimer's disease, has been synthesized and characterized by FT-IR, and (1)H and (13)C NMR spectroscopic analyses. The crystal structure was analysed using powder diffraction as no suitable single crystal was obtained. The piperazine ring has a chair conformation, while the cyclohexene ring assumes a half-chair conformation. The crystal packing is mediated by weak contacts, principally by complementary intermolecular N-H···O hydrogen bonds that connect successive molecules into a chain. Further stabilization is provided by weak C-H···N contacts and by a weak intermolecular C-H···π interaction.