Crystal structure of palbociclib isethionate Form B, (C24H30N7O2)(C2H5O4S)

The crystal structure of palbociclib isethionate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional theory techniques. Palbociclib isethionate crystallizes in space group P-1 (#2) with a = 8.71334(4), b = 9.32119(6), c = 17.73725(18) Å, α = 80.0260(5), β = 82.3579(3), γ = 76.1561(1)°, V = 1371.282(4) Å3, and Z = 2. The crystal structure is dominated by cation⋯anion and cation⋯cation hydrogen bonds, which result in layers roughly parallel to the (104) plane. Both hydrogen atoms on the protonated nitrogen atom of the pyrimidine ring participate in strong hydrogen bonds to the anions. One proton binds to the sulfonate group, while the other bonds to the hydroxyl group of the isethionate anion. The hydroxyl group of the anion acts as a donor to a ketone oxygen atom in the cation. There are also strong N–H⋯N hydrogen bonds, which occur in pairs linking the cations into dimers with rings having a graph set R2,2(8). The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™.

Crystal structure of edoxaban tosylate monohydrate Form I, (C24H31ClN7O4S)(C7H7O3S)(H2O)

The crystal structure of edoxaban tosylate monohydrate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Edoxaban tosylate monohydrate crystallizes in space group P21 (#4) with a = 7.55097(2), b = 7.09010(2), c = 32.80420(21) Å, β = 96.6720(3)°, V = 1744.348(6) Å3, and Z = 2. The crystal structure consists of alternating layers of edoxaban cations and tosylate anions along the c-axis. The water molecules lie near the sulfonate end of the tosylate anions. The solid-state conformation of the edoxaban cation is determined by intermolecular interactions. The protonated nitrogen atom forms a strong N–H⋯O hydrogen bond to one of the tosylate oxygens. Only one of the water molecule hydrogens acts as a donor in an O–H⋯O hydrogen bond. The tosylate oxygens act as acceptors in a number of C–H⋯O hydrogen bonds. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™.

Crystal structure of (E)-doxepin hydrochloride, C19H22NOCl

The crystal structure of (E)-doxepin hydrochloride has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. (E)-doxepin hydrochloride crystallizes in space group P21/a (#14) with a = 13.78488(7), b = 8.96141(7), c = 14.30886(9) Å, β = 96.5409(5)°, V = 1756.097(12) Å3, and Z = 4. There is a strong discrete hydrogen bond between the protonated nitrogen atom and the chloride anion. There are six C–H⋯Cl hydrogen bonds between the methyl groups and the chloride, as well as additional hydrogen bonds from methylene groups and the vinyl proton. The hydrogen bonds are important in determining the solid-state conformation of the cation. The compound is essentially isostructural to amitriptyline hydrochloride. The powder pattern is included in the Powder Diffraction File™ as entry 00-066-1613.

A study on the aromaticity and magnetic properties of N-confused porphyrins

In this paper, topological resonance energy (TRE) methods were used to describe the global aromaticity of nitrogen confused porphyrin (NCP) isomers. The TRE results show that all NCP isomers exhibit lower aromaticity than the normal porphyrins, and their aromaticity decreases as the number of confused pyrrole rings in the molecule increases. In the NCPs, global aromaticity decreases as the distance between the nitrogen atoms increases. The bond resonance energy (BRE) and circuit resonance energy (CRE) indices were applied to study local aromaticity and conjugated pathways. Both the BRE and CRE indices revealed that individual pyrrolic subunits maintain their strong aromatic character and are the main source of global aromaticity. Ring currents (RC) were analysed using the Hückel–London model. RC results revealed that the macrocyclic electron conjugation pathway is the main source of diatropicity. As the number of confused pyrrole rings in the molecule increases, its diatropicity gradually decreases. In the confused pyrrole rings of the NCP isomers, the diatropic RC passing through the β -positions is always weaker than that passing through the inner sections. This is unrelated to the location of the protonated or non-protonated nitrogen atom at the periphery of the molecule and must be ascribed to the unique properties of the confused pyrrole rings.

C4–C5 fused pyrazol-3-amines: when the degree of unsaturation and electronic characteristics of the fused ring controls regioselectivity in Ullmann and acylation reactions

The regioselectivity of Ullmann and acylation reactions of C4–C5 fused pyrazol-3-amines is predicted using DFT calculations of the most stable tautomer (1H- or 2H-pyrazole) and occur, mainly, at the NH and non-protonated nitrogen atom, respectively.

An abinitio and ion cyclotron resonance study of the protonation of borazine

The gas phase ion–molecule reactions and proton affinity of borazine have been investigated by both theoretical ab initio and ion cyclotron resonance techniques. The experimental proton affinity has been determined from competitive proton transfer equilibria with standard reference bases and found to be 196.4 ± 0.2 kcal/mol. Ion–molecule reaction schemes for reaction of borazine molecular ions have been proposed. Ab initio calculations find the proton affinity of borazine to be 203.4 kcal/mol and the most energetically favorable structure of the borazinium ion is one in which very little structural change occurs relative to neutral borazine with the exception of the geometry about the protonated nitrogen atom. Charge distributions and bond lengths are used to explain bonding changes upon protonation.

Hydrolysis and ammonolysis of EDTA in aqueous solution

The hydrolysis and ammonolysis of EDTA were studied in aqueous solution over a range of temperatures and at various pH values with the aid of nmr, gc, and gc – mass spectroscopic techniques. At high pH in the presence of ammonia, both ammonolysis and hydrolysis occur with the production of N-(2-aminoethyl)iminodiacetic acid (UEDDA), N-(2-hydroxyethyl)-iminodiacetic acid (HEIDA), and iminodiacetic acid (IDA) in molar ratios such that [IDA] = [UEDDA] + [HEIDA]. The first-order rate constant for the disappearance of EDTA at 175 °C in dilute aqueous ammonia is 8.6 × 10−5 s−1 whereas in the absence of ammonia its hydrolysis constant is 4.2 × 10−5 s−1. The value of ΔH0 for this reaction is approximately 35 kcal/mol. When methylamine replaces ammonia, the UEDDA is replaced by N-(2-methylaminoethyl)iminodiacetic acid. The rate of hydrolysis is increased by the presence of a tertiary amine but the latter does not become incorporated into the reaction products. A reaction mechanism is proposed involving bimolecular SN2 attack by base on a carbon atom of the ethylene bridge adjacent to a protonated nitrogen atom of EDTA with concomitant displacement of iminodiacetic acid.

Crystal Structure of Bis[hexakis(dimethylamino)cyclotriphosphonitrilium] Tetrachlorocobaltate(II)

Crystals of the title compound, [N3P3(NMe2)6H]2CoCl4, are orthorhombic, a = 34.623, b = 13.964, c = 10.486 Å, Z = 4, space group P212121. The structure was determined by Patterson and electron-density methods and refined by full-matrix least-squares procedures to R = 0.088 for 2178 observed reflexions. Both rings are slightly non-planar, with three distinct pairs of NP bonds: commencing at the protonated nitrogen atom, 1.68, 1.56, and 1.58 Å. The CoCl42− ion is tetrahedral and is hydrogen bonded to both rings, N—H … Cl = 3.32, 3.36 Å.