Synthesis, Characterization, X-ray Molecular Structure, Antioxidant, Antifungal, and Allelopathic Activity of a New Isonicotinate-Derived meso-Tetraarylporphyrin.

The present article describes the synthesis of an isonicotinate-derived meso-arylporphyrin, that has been fully characterized by spectroscopic methods (including fluorescence spectroscopy), as well as elemental analysis and HR-MS. The structure of an n-hexane monosolvate has been determined by single-crystal X-ray diffraction analysis. The radical scavenging activity of this new porphyrin against the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical has been measured. Its antifungal activity against three yeast strains (C. albicans ATCC 90028, C. glabrata ATCC 64677, and C. tropicalis ATCC 64677) has been tested using the disk diffusion and microdilution methods. Whereas the measured antioxidant activity was low, the porphyrin showed moderate but encouraging antifungal activity. Finally, a study of its effect on the germination of lentil seeds revealed interesting allelopathic properties.

Synthesis of New Cobalt(III) Meso-Porphyrin Complex, Photochemical, X-ray Diffraction, and Electrical Properties for Photovoltaic Cells.

The present work describes the preparation and characterization of a new cobalt(III) porphyrin coordination compound named (chlorido)(nicotinoylchloride)[meso-tetra(para-chlorophenyl)porphyrinato]cobalt(III) dichloromethane monosolvate with the formula [CoIII(TClPP)Cl(NTC)]·CH2Cl2 (4). The single-crystal X-ray molecular structure of 4 shows very important ruffling and waving distortions of the porphyrin macrocycle. The Soret and Q absorption bands of 4 are very red-shifted as a consequence of the very distorted porphyrin core. This coordination compound was also studied by fluorescence and cyclic voltammetry. The efficiency of our four porphyrinic compounds-the H2TClPP (1) free-base porphyrin, the [CoII(TClPP)] (2) and [CoIII(TClPP)Cl] (3) starting materials, and the new Co(III) metalloporphyrin [CoIII(TClPP)Cl(NTC)]·CH2Cl2 (4)-as catalysts in the photochemical degradation was tested on malachite green (MG) dye. The current voltage of complexes 3 and 4 was also studied. Electrical parameters, including the saturation current density (Js) and barrier height (ϕb), were measured.

The role of free space in photochemical reactions in crystals at high pressure - the case of 9-methylanthracene.

The influence of pressure on the course of [4+4] photodimerization in crystals of 9-methylanthracene is presented. The studies were performed at 0.1 and 0.4 GPa. As a result of the reaction at high pressure, crystals of the pure product were obtained, which allowed for monitoring of the reaction until its completion. The initial increase in the unit-cell volume caused by the reaction under ambient conditions was reduced at high pressure due to the decrease in the void volume. Despite the smaller size of the void volume at high pressure, dimer molecules formed during the reaction changed the orientation of the monomer molecules in the crystal structure. The size of the voids above the terminal rings of the monomers correlates with the position of the terminal rings in the dimer. The reaction rate increased at high pressure, indicating that the decrease in the distance between adjacent monomers caused by pressure dominates over the decrease in the void volume. This distance is statistically constant as the reaction progresses, contrary to the reaction at ambient pressure.

Structural reasons for the formation of multicomponent products and the influence of high pressure.

(S)-(-)-1-Phenylethanaminium 4-(2,4,6-triisopropylbenzoyl)benzoate (S-PEATPBB) undergoes a photochemical reaction in its crystalline form upon UV irradiation and forms three different products: the first product is the result of a Yang cyclization with the participation of the δ-H atom of o-isopropyl (product D) and the second and third products are obtained via a Norrish-Yang reaction with the involvement of the γ-H atom of 2-isopropyl (product P) and 6-isopropyl (product Z). These products are formed in different proportions (D > P >> Z). The path and kinetics of the reaction were monitored step-by-step using crystallographic methods, both under ambient and high-pressure conditions. The reactivity of S-PEATPBB depends strongly on the geometry of the reaction centre and the volume of the reaction cavity. Due to the geometrical preferences making the cyclization reaction easier to proceed, product D dominates over the other products, while the formation of product Z becomes difficult or almost impossible at high pressure. The reaction proceeds with an increase of the unit-cell volume, which, suppressed by high pressure, results in a significant decrease of the reaction rate. The crystal lattice of S-PEATPBB shows high elasticity. The quality of the partially reacted crystal remains the same after decompression from 0.75 GPa to 0.1 MPa.

Crystal Structure Determination of 4-[(Di-p-tolyl-amino)-benzylidene]-(5-pyridin-4-yl-[1,3,4]thiadiazol-2-yl)-imine along with Selected Properties of Imine in Neutral and Protonated Form with Camforosulphonic Acid: Theoretical and Experimental Studies.

The crystal structure was determined for the first time for 4-[(di-p-tolyl-amino)benzylidene]-(5-pyridin-4-yl-[1,3,4]thiadiazol-2-yl)-imine (trans-PPL9) by X-ray diffraction. The imine crystallized in the monoclinic P21/n space group with a = 18.9567(7) Å, b = 6.18597(17) Å, c = 22.5897(7) Å, and ß = 114.009(4)°. Intermolecular interactions in the PPL9 crystal were only weak C-H⋯N hydrogen bonds investigated using the Hirshfeld surface. The electronic and geometric structure of the imine were investigated by the density functional theory and the time-dependent density-functional theory. The properties of the imine in neutral and protonated form with camforosulphonic acid (CSA) were investigated using cyclic voltammetry, UV-vis and 1H NMR spectroscopy. Theoretical and experimental studies showed that for the 1:1 molar ratio the protonation occured on nitrogen in pyridine in the PPL9 structure, as an effect of Brönsted acid-base interactions. Thermographic camera was used to defined defects in constructed simple devices with ITO/PPL9 (or PPL9:CSA)/Ag/ITO architecture. In conclusion, a thermally stable imine was synthesized in crystalline form and by CSA doping, a modification of absorption spectra together with reduction of overheating process was observed, suggesting its potential application in optoelectronics.

Effect of the coordination of π-acceptor 4-cyanopyridine ligand on the structural and electronic properties of meso-tetra(para-methoxy) and meso-tetra(para-chlorophenyl) porphyrin cobalt(ii) coordination compounds. Application in the catalytic degradation of methylene blue dye.

To examine the influence of both the important π-acceptor character of the 4-cyanopyridine ligand and the nature of the para-substituted phenyls of meso-porphyrins on the electronic, electrochemical and structural properties of cobaltous metalloporphyrins, we prepared and fully characterized two coordination compounds: the (4-cyanopyridine)[meso-tetra(para-methoxyphenyl)porphyrinato]cobalt(ii) and the (4-cyanopyridine)[meso-tetra(para-chlorophenyl)porphyrinato]cobalt(ii) with the [CoII(TMPP)(4-CNpy)] and [CoII(TClPP)(4-CNpy)] formulas (complexes 1-2). The solution structures of compounds 1-2 were confirmed by 1H NMR spectroscopy and mass spectrometry methods. They were further characterized by cyclic voltammetry and photoluminescence studies. The X-ray molecular structure data show that the Co-TClPP-4-NCpy derivative (2) exhibits high ruffling deformation compared to that of the Co-TMPP-4-CNpy species (1). Notably, the crystal packing of complex 1 shows the formation of Co⋯Co supramolecular dimers with a distance of 5.663 Å. As an application of our two cobaltous compounds, an investigation involving complexes 1-2 in the degradation of the methylene blue dye in the presence and absence of H2O2 in aqueous solutions was carried out. These promising results show that 1-2 can be used as catalysts in the degradation processes of dyes.

Three-Component Reaction of Benzylamines, Diethyl Phosphite and Triethyl Orthoformate: Dependence of the Reaction Course on the Structural Features of the Substrates and Reaction Conditions.

The reaction between benzyl amines, triethyl orthoformate, and diethyl phosphite affords either bisphosphonic (compound 1) or N-benzylaminobenzylphosphonic (compound 2) acid depending on the reaction conditions. The final output of the reaction can be manipulated by the choice of reaction conditions, particularly the molar ratio of substrates.

Crystal structure of an unknown solvate of (piperazine-κN){5,10,15,20-tetra-kis-[4-(benzo-yloxy)phen-yl]porphyrinato-κ(4) N}zinc.

The title compound, [Zn(C72H44N4O8)(C4H10N2)] or [Zn(TPBP)(pipz] (where TPBP and pipz are 5,10,15,20-tetra-kis-[4-(benzo-yloxy)phen-yl]porphyrinato and piperazine ligands respectively), features a distorted square-pyramidal coordin-ation geometry about the central Zn(II) atom. This central atom is chelated by the four N atoms of the porphyrinate anion and further coordinated by a nitro-gen atom of the piperazine axial ligand, which adopts a chair confirmation. The average Zn-N(pyrrole) bond length is 2.078 (7) Šand the Zn- N(pipz) bond length is 2.1274 (19) Å. The zinc cation is displaced by 0.4365 (4) Šfrom the N4C20 mean plane of the porphyrinate anion toward the piperazine axial ligand. This porphyrinate macrocycle exhibits major saddle and moderate ruffling deformations. In the crystal, the supra-molecular structure is made by parallel pairs of layers along (100), with an inter-layer distance of 4.100 Šwhile the distance between two pairs of layers is 4.047 Å. A region of electron density was treated with the SQUEEZE [Spek (2015 ▸). Acta Cryst. C71, 9-18] procedure in PLATON following unsuccessful attempts to model it as being part of disordered n-hexane solvent and water mol-ecules. The given chemical formula and other crystal data do not take into account these solvent mol-ecules.

Characterization of the mixed axial ligand complex (4-cyanopyridine)(imidazole)(tetramesitylporphinato)iron(iii) perchlorate. Stabilization by synergic bonding.

The reaction of [Fe(TMP)(OClO3)], where TMP is the dianion of tetramesitylporphyrin, with a combination of a strong π-acceptor ligand and a π-donating imidazole can lead to the preparation of mixed-ligand complexes [Fe(Porph)(4-CNPy)(L)]+ where L is imidazole itself or 1-acetylimidazole and 4-cyanopyridine is the strong π acceptor ligand. The stability of the new mixed-ligand pair is the presumed result of synergic bonding between the two axial ligands. The molecular structure and other characterization of the new mixed axial ligand complex, [Fe(TMP)(4-CNPy)(HIm)]ClO4 is described. The axial ligands have a relative perpendicular arrangement with Fe-N(imidazole) = 1.945 Å and Fe-N(pyridine) = 2.021 Å The average equatorial Fe-Np distance is 1.963 Å, which is consistent with the S4-ruffled TMP core. Despite the relative perpendicular arrangement of axial ligands, the EPR spectrum of the complex is a rhombic signal and not a large gmax signal. The EPR g-values are g1 = 3.05, g2 = 2.07, and g3 = 1.22. A quadrupole doublet was seen in the Mössbauer spectrum with an isomer shift of 0.197 mm/s and quadrupole splitting of 1.935 mm/s. Two crystalline forms of [Fe(TMP)(4-CNPy)(HIm)]ClO4 have been characterized; the two forms differ only in the solvent content of the lattice. Crystal data for form A: a = 15.432 (12) Å, b = 20.696 (2) Å, c = 19.970 (5) Å, and ß = 99.256 (14)°, monoclinic, space group P21/n, V = 6295 (2) Å3, Z = 4, formula FeCl3O4N8C69H69, 8397 observed data, R1 = 0.086, wR2 = 0.210, refinement on F2. Crystal data for form B: a = 15.267 (3) Å, b = 20.377 (6) Å, c = 19.670 (4) Å, and ß = 98.14 (1)°, monoclinic, space group P21/n, V = 6058 (4) Å3, Z = 4, formula C65.25H60.5Cl1.5FeN8O4, 5464 observed data, R1 = 0.096, wR2 = 0.112, refinement on F.

Monitoring photo-induced transformations in crystals of 2,6-difluorocinnamic acid under ambient conditions.

Several conditions need to be fulfilled for a photochemical reaction to proceed in crystals. Some of these conditions, for example, geometrical conditions, depend on the particular type of photochemical reaction, but the rest are common for all reactions. The mutual directionality of two neighbouring molecules determines the kind of product obtained. The influence of temperature on the probability of a photochemical reaction occurring varies for different types of photochemical reaction and different compounds. High pressure imposed on crystals also has a big influence on the free space and the reaction cavity. The wavelength of the applied UV light is another factor which can initiate a reaction and sometimes determine the structure of a product. It is possible, to a certain degree, to control the packing of molecules in stacks by using fluoro substituents on benzene rings. The crystal and molecular structure of 2,6-difluorocinnamic acid [systematic name: 3-(2,6-difluorophenyl)prop-2-enoic acid], C9H6F2O2, (I), was determined and analysed in terms of a photochemical [2 + 2] dimerization. The molecules are arranged in stacks along the a axis and the values of the intermolecular geometrical parameters indicate that they may undergo this photochemical reaction. The reaction was carried out in situ and the changes of the unit-cell parameters during crystal irradiation by a UV beam were monitored. The values of the unit-cell parameters change in a different manner, viz. cell length a after an initial increase starts to decrease, b after a decrease starts to increase, c increases and the unit-cell volume V after a certain increase starts to decrease. The structure of a partially reacted crystal, i.e. containing both the reactant and the product, namely 2,6-difluorocinnamic acid-3,4-bis(2,6-difluorophenyl)cyclobutane-1,2-dicarboxylic acid (0.858/0.071), 0.858C9H6F2O2·0.071C18H12F4O4, obtained in situ, is also presented. The powder of compound (I) was irradiated with UV light and afterwards crystallized [as 3,4-bis(2,6-difluorophenyl)cyclobutane-1,2-dicarboxylic acid toluene hemisolvate, C18H12F4O4·0.5C7H8] in a space group different from that of the crystal containing the in-situ dimer.

Crystal structure of (4-cyano-pyridine-κN){5,10,15,20-tetrakis[4-(benzoyloxy)phenyl]porphyrinato-κ(4) N}zinc-4-cyano-pyridine (1/1).

In the title compound, [Zn(C72H44N4O8)(C6H4N2)]·C6H4N2 or [Zn(TPBP)(4-CNpy]·(4-CNpy) [where TPBP and 4-CNpy are 5,10,15,20-(tetra-phenyl-benzoate)porphyrinate and 4-cyano-pyridine, respectively], the Zn(II) cation is chelated by four pyrrole-N atoms of the porphyrinate anion and coordinated by a pyridyl-N atom of the 4-CNpy axial ligand in a distorted square-pyramidal geometry. The average Zn-N(pyrrole) bond length is 2.060 (6) Šand the Zn-N(4-CNpy) bond length is 2.159 (2) Å. The zinc cation is displaced by 0.319 (1) Šfrom the N4C20 mean plane of the porphyrinate anion toward the 4-cyano-pyridine axial ligand. This porphyrinate macrocycle exhibits major saddle and moderate ruffling and doming deformations. In the crystal, the [Zn(TPBP)(4-CNpy)] complex mol-ecules are linked together via weak C-H⋯N, C-H⋯O and C-H⋯π inter-actions, forming supra-molecular channels parallel to the c axis. The non-coordinating 4-cyano-pyridine mol-ecules are located in the channels and linked with the complex mol-ecules, via weak C-H⋯N inter-actions and π-π stacking or via weak C-H⋯O and C-H⋯π inter-actions. The non-coordinating 4-cyano-pyridine mol-ecule is disordered over two positions with an occupancy ratio of 0.666 (4):0.334 (4).

The crystal and molecular structure of sodium 4-(2,4,6-triisopropylbenzoyl)benzoate in terms of the photochemical behaviour of the anion.

Contrary to the known 4-(2,4,6-triisopropylbenzoyl)benzoate salts, di-µ-aqua-bis[tetraaquasodium(I)] bis[4-(2,4,6-triisopropylbenzoyl)benzoate] dihydrate, [Na2(H2O)10](C23H27O3)2·2H2O, (1), does not undergo a photochemical Norrish-Yang reaction in the crystalline state. In order to explain this photochemical inactivity, the intermolecular interactions were analyzed by means of the Hirshfeld surface and intramolecular geometrical parameters describing the possibility of a Norrish-Yang reaction were calculated. The reasons for the behaviour of the title salt are similar crystalline environments for both the o-isopropyl groups in the anion, resulting in similar geometrical parameters and orientations, and that these interaction distances differ significantly from those found in salts where the photochemical reaction occurs.

X-ray crystal structure, vibrational spectra and DFT calculations of 3-chloro-7-azaindole: a case of dual N-H⋯N hydrogen bonds in dimers.

3-Chloro-7-azaindole (3Cl7AI) is the carrier ligand in a new anticancer platinum(II) agent cis-[PtCl2(3Cl7AI)2]. In this work 3Cl7AI has been studied by a single crystal X-ray diffraction, infrared and Raman spectroscopy and density functional calculations. The compound crystallizes in the monoclinic system, space group P21/n, with a=12.3438(3), b=3.85964(11), c=14.4698(4)Å, ß=100.739(2)°, V=677.31(3)Å(3) and Z=4. In the crystal, a pair of 3Cl7AI molecules forms a centrosymmetric dimer linked by the moderately strong dual N-H⋯N hydrogen bonds. The nitrogen atom in the pyrrole ring acts as the proton donor, while the nitrogen atom in the pyridine ring is the proton acceptor. The FT-IR and FT-Raman spectra (3500-60 cm(-1)) have been recorded. The theoretical studies on the molecular structures and vibrational spectra of the monomeric and dimeric forms of 3Cl7AI and its N-deuterated derivative were performed using the B3LYP method with 6-311++G(d,p) basis set. The theoretically predicted Raman spectrum for the dimer shows very good agreement with experiment. Detailed vibrational assignments for the two isotopomers have been made on the basis of the calculated potential energy distributions (PEDs). The dual N-H⋯N hydrogen bonds in 3Cl7AI dimer are characterized by a very broad and complicated structure of the absorption band between 3300 and 2500 cm(-1), which is caused by multiple Fermi resonances between the N-H stretching vibration and various combinations bands.

Conformational Distortions of π-Cation Radical (ß-Oxoporphyrin)copper(II) Derivatives: [Cu(2,7,12-TrioxoOEHP)][SbCl(6)] and [Cu(2,7-DioxoOEiBC)][SbCl(6)].

The preparation and characterization of two π-cation radical derivatives of copper ß-oxo porphyrins is described. [3,3,8,8,13,13,17,18-Octaethyl-(3H,8H,13H)-porphine-2,7,12-trionato (2-)] copper π-cation radical, [Cu(2,7,12-trioxoOEHP(.))](+), and [3,3,8,8,12,13,17,18-octaethyl-(3H,8H)-porphine-2,7-dionato(2-)] copper π-cation radical, [Cu(2,7-dioxoOEiBC(.))](+), have been prepared and characterized by single-crystal X-ray determinations, UV/vis/NIR, and IR spectroscopies. Both molecules have modest distortion from the planarity and show monomeric units in the solid state. [Cu(2,7-dioxoOEiBC(.))](+) shows a concentration dependent near-IR band at 1410 nm. Crystal data for [Cu(2,7,12-trioxoOEHP(.))][SbCl(6)]: tetragonal, space group P4(2)/n, a = 31.085 (14) Å, c = 9.410 (4) Å, V = 9093 Å(3), Z = 8, T = 127 K. Crystal data for [Cu(2,7-dioxoOEiBC(.))][SbCl(6)]: monoclinic, space group P2(1)/n, a = 9.655 (4) Å, b = 20.592 (8) Å, c = 43.347 (17) Åß = 89.97(1)(°), V = 8618. Å(3), Z = 8, T = 100 K.

Monitoring structural transformations in crystals. 13. On photocyclization in 2,3,4,5,6-pentamethylbenzophenone, 1,3-diphenylbutan-1-one and 2,4,6-triisopropyl-4'-methoxybenzophenone.

The geometrical parameters governing the potential for the photocyclization reaction occurring in crystals of 2,3,4,5,6-pentamethylbenzophenone, C(18)H(20)O, (I), 1,3-diphenylbutan-1-one, C(16)H(16)O, (II), and 2,4,6-triisopropyl-4'-methoxybenzophenone, C(23)H(30)O(2), (IV), have been evaluated. Compound (IV) undergoes photocyclization but (I) and (II) do not, despite the fact that their geometrical parameters appear equally favourable for reaction. The structure of the partially reacted crystal of the photoactive compound, i.e. 2,4,6-triisopropyl-4'-methoxybenzophenone-3,5-diisopropyl-7-(4-methoxyphenyl)-8,8-dimethylbicyclo[4.2.0]octa-1,3,5-trien-7-ol (9/1), 0.90C(23)H(30)O(2).0.10C(23)H(30)O(2), (III), was also determined, providing structural evidence for the reactivity of the compound. It has been found that the carbonyl group of the photoactive compound reacts with one of the two o-isopropyl groups. The study has shown that the intramolecular geometrical parameters are not the only factors influencing the reactivity of compounds in crystals.

2-Oxo-2-phenyl-N-[(R)-1-phenylethyl]acetamide and N,N-dimethyl-2-(1-naphthyl)-2-oxoacetamide: possibility of Yang photocyclization in a crystal.

The crystal structures of 2-oxo-2-phenyl-N-[(R)-1-phenylethyl]acetamide, C16H15NO2, (I), and N,N-dimethyl-2-(1-naphthyl)-2-oxoacetamide, C14H13NO2, (II), were determined in an attempt to understand the reason for the lack of Yang photocyclization in their respective crystals. In the case of (I), the long distance between the O atom of the carbonyl group and the gamma-H atom, and between the C atom of the carbonyl group and the gamma-C atom, preclude Yang photocyclization. For (II), the deviation of the gamma-H atom from the plane of the carbonyl group and interactions between the naphthalene rings are regarded as possible reasons for the chemical inertia. The two independent molecules of (I) differ in their conformation. N-H...O hydrogen bonds link molecules of (I) into chains extended along the b axis.

rac-3-Benzoyl-2-methylpropionic acid and its organic salts: possibilities of Yang photocyclization in crystals.

The analysis of the crystal structures of rac-3-benzoyl-2-methylpropionic acid, C(11)H(12)O(3), (I), morpholinium rac-3-benzoyl-2-methylpropionate monohydrate, C(4)H(10)NO(+).C(11)H(11)O(3)(-).H(2)O, (II), pyridinium [hydrogen bis(rac-3-benzoyl-2-methylpropionate)], C(5)H(6)N(+).(H(+).2C(11)H(11)O(3)(-)), (III), and pyrrolidinium rac-3-benzoyl-2-methylpropionate rac-3-benzoyl-2-methylpropionic acid, C(4)H(10)N(+).C(11)H(11)O(3)(-).C(11)H(12)O(3), (IV), has enabled us to predict and understand the behaviour of these compounds in Yang photocyclization. Molecules containing the Ar-CO-C-C-CH fragment can undergo Yang photocyclization in solvents but they can be photoinert in the crystalline state. In the case of the compounds studied here, the long distances between the O atom of the carbonyl group and the gamma-H atom, and between the C atom of the carbonyl group and the gamma-C atom preclude Yang photocyclization in the crystals. Molecules of (I) are deprotonated in a different manner depending on the kind of organic base used. In the crystal structure of (III), strong centrosymmetric O...H...O hydrogen bonds are observed.

Stereoselective C9 carbon-carbon couplings of quinine: synthesis and conformational analysis of new C2-symmetric dimers.

An unexpected stereoselective direct dimerization occurred when 9-quinine halide was treated with butyllithium. The reaction of either (9S)- or (9R)-chloroquinine gave the same C2-symmetric dimer with 9R configuration (X-ray structure). A tentative mechanism involving radical recombination is discussed. This highly congested dimer forms two atropisomers, and their reversible interconversion was studied by NMR. Another C2-symmetric (9S)-quinine dimer connected solely by carbon-carbon bonds was obtained by the stereoselective coupling of bis(arylbromomagnesium) derivative with (9S)-chloroquinine.

Monitoring structural transformations in crystals. 12. Course of an intramolecular [4 + 4] photocycloaddition in a crystal.

Variations in crystal and molecular structures, brought about by the intramolecular [4 + 4] photocycloaddition of bi(anthracene-9,10-dimethylene), were monitored using X-ray diffraction. The cell volume increased by 0.8% until the reaction was ca 40% complete, and afterwards decreased by 1.6% during the remainder of the photoreaction. The changes of the a and b lattice parameters were correlated with the changes of the molecular shape and packing. The distance between the directly reacting C atoms varied in a manner not observed for other photochemical reactions in crystals. It was constant until ca 20% photoreaction progress, then decreased, and later stabilized from ca 40% photoreaction progress. This phenomenon was explained by interplay between stress resulting from the presence of product molecules and the rigidity of reactant molecules. Changes of the orientation of molecules during the photoreaction were smaller than in the case of other monitored photochemical reactions in crystals owing to similarities in the shape and packing of reactant and product molecules. Weak C-H...pi hydrogen bonds exist among reactant molecules in the pure reactant and partly reacted crystals.

Stereoselective C9 arylation and vinylation of Cinchona alkaloids.

A simple and efficient method for the highly stereoselective C-9 arylation and vinylation of Cinchona alkaloids was developed. Both 9S- and 9R-chloroquinine with PhMgBr yielded 9S-phenylquinine (X-ray structure). The reactions with various aryl and vinyl Grignard reagents resulted in the series of 9S-aryl and vinyl alkaloid derivatives. The stereochemical outcome was rationalized by coordination of the magnesium atom to the quinuclidine nitrogen, thus directing the nucleophilic attack at the C-9 stereogenic center.