Teresa Borowiak

Highly selective synthesis of (E)-N-aryl-N-(1-propenyl) ethanamides via isomerization of N-allyl ethanamides catalyzed by ruthenium complexes

Abstract A convenient and highly selective method of synthesis of (E)-N-aryl-N-(1-propenyl)ethanamides via isomerization of respective N-allyl-N-arylethanamides catalyzed by [RuClH(CO)(PPh3)3] has been described. N-Allyl-N-arylethanamides have been obtained by allylation of respective N-arylethanamides under PTC conditions. It is proposed that the observed selectivity of the double bond migration to (E)-enamides is due to the interaction of the arene ring with the Ru atom in the transition state.

Structure of 1,8-bis(dimethylamino)naphthalene hydrobromide dihydrate

Abstract1,8-bis(dimethylamino)naphthalene hydrobromide dihydrate, C14H19N2+Br · 2H2O, crystallizes in the space groupPnma witha=7.264(1),b=11.794(1),c=18.986 (2) Å,Z=4,Dm=1.34 g cm−3,DX=1350 kg cm−3. The structure was determined by Patterson and Fourier methods and refined to anR factor of 0.038. The 1,8-bis(dimethylamino)naphthalene cation has mirror symmetry, with the mirror plane passing along the C(9)-C(10) bond. The two N atoms are moved slightly out of the naphthalene plane. Theperi interactions are discussed in relation to aromaticity and to the N-C (ring) bond lengths. The structure contains channels of H bonds (Br− and water molecules) parallel toa which alternate with channels of cations in theb andc directions. One of the water molecules is disordered.

Synthesis and structure of (+)-2-thionosparteine, a new thioanalogue of lupanine

Abstract (+)-2-Thionosparteine was obtained for the first time. 1H and 13C NMR spectroscopy were used for quantitative determination of conformational equilibrium in solution. The X-ray structure revealed two molecules in the asymmetric unit that differ substantially in their conformations. Weak CH⋯S interactions are characterized and compared with the intramolecular hydrogen bond CH⋯O in the crystal structure of 2-oxosparteine.

Comparative structural analysis of sparteine derivatives and their protonated salts

Abstract X-ray results on derivatives of sparteine and its salts with mineral acids have been reviewed. Attention has been paid to the factors which cause configurational and conformational transformations of the molecular skeleton.

Topochemical bias in the hydrogen-bonded networks of guanidinium carboxybenzenesulfonates

Herein we describe the changes in the packing patterns and discuss the structural modifications in guanidinium carboxybenzenesulfonates G·CBS [C(NH2)3]+[XC6H4SO3]− (where X is the carboxylic group) compared with those in guanidinium benzenesulfonate G·BS. Generally, the one-dimensional arrangements in all three crystals comprise the same ribbon formations. However, the further organization of the ribbons is significantly different in G·CBS. We analyse the donor and acceptor efficacy of the additional functional group to disrupt some of the basic hydrogen bonds between the guanidinium and the sulfonium portions in G·BS. Since the carboxylic group introduces a mismatching of the sites on the counter ions, the changes in the symmetry relations essentially depend upon the topology of the substituent X, which results in modified packing patterns. All engineering peculiarities are analysed with respect to the symmetry constraints and geometrical demands of the packing forces.

IV. Thionalogues of sparteine lactams. (+)-15-Thionosparteine and its perchlorate salt

Abstract (+)-15-Thionosparteine and its perchlorate have been obtained and characterized by IR and NMR spectroscopy as well as by X-ray diffraction analysis. Introduction of the thiolactam group into the cis-quinolizidine part of the sparteine skeleton causes conformational rigidity of this fragment in the solid state. Moreover, the conformations in solution, established by NMR and in the solid state are similar.

10-Hydroxybenzo[h]quinoline

The crystal structure of 10-hydroxybenzo[h]quinoline, C 13 H 9 NO, has been determined. The asymmetric part of the unit cell comprises two almost planar molecules. A strong intramolecular O-H...N hydrogen bond closes the six-membered ring. The geometrical features of the molecule suggest that it can be regarded as a 2-phenylpyridine with a fused double bond. In the crystal structure there are alternate layers of the two symmetry-independent molecules.

Crystal and molecular structure of 13-oxolupanine

The title compound, C15H22N2O2, is monoclinic:P21,a=10.876(2),b=8.620(2),c=7.390(2) Å, β=99.2(2)°,Z=2. TheA/B ring junction configuration isquasi-trans, and theC/D junction istrans. RingA has a conformation intermediate between sofa and half-chair; ringsB,C, andD are in chair, boat, and distorted chair conformations, respectively.

Crystal and molecular structure of 2-phenylsparteine perchlorate

The structure of the title compound has been solved: it comprises two ionic components. The cation skeleton is built of two quinolizidine moieties with atrans A/B and acis C/D configuration. All four heterocyclic rings adopt a chair conformation. Owing to an N(16) protonation, an intramolecular hydrogen bond has been formed with an N(1)⋯N+(16) distance of 2.742(4) Å. The protonation and subsequent hydrogen-bond formation are the main factors that cause an inversion of the N(16) configuration. The phenyl substituent at C(2) has weakened the intramolecular hydrogen bond in comparison with that of the 2-methylsparteine cation. The ClO4− anions are disordered with occupancy factors of 0.70 and 0.30.

Charge-density analysis using multipolar atom and spherical charge models: 2-methyl-1,3-cyclopentanedione, a compound displaying a resonance-assisted hydrogen bond.

The experimental charge-density distribution in 2-methyl-1,3-cyclopentanedione in the crystal state was analyzed by synchrotron X-ray diffraction data collection at 0.33 Å resolution. The molecule in the crystal is in the enol form. The experimental electron density was refined using the Hansen-Coppens multipolar model and an alternative modeling, based on spherical atoms and additional charges on the covalent bonds and electron lone-pair sites. The crystallographic refinements, charge-density distributions, molecular electrostatic potentials, dipole moments and intermolecular interaction energies obtained from the different charge-density models were compared. The experimental results are also compared with the theoretical charge densities using theoretical structure factors obtained from periodic quantum calculations at the B3LYP/6-31G** level. A strong intermolecular O-H···O hydrogen bond connects molecules along the [001] direction. The deformation density maps show the resonance within the O=C-C=C-OH fragment and merged lone pair lobes on the hydroxyl O atom. This resonance is further confirmed by the analysis of charges and topology of the electron density.