Pramod B. Pansuriya

Bisthiourea: thermal and structural investigation

Bisthiourea derivatives 1,1′-(ethane-1,2-diyl)bis(3-phenylthiourea), 1,1′-(propane-1,3-diyl)bis(3-phenylthiourea), and 1,1′-(butane-1,4-diyl)bis(3-phenylthiourea) have been synthesized and characterized by IR, 1H NMR, and 13C NMR. Suitable crystals of 1,1′-(propane-1,3-diyl)bis(3-phenylthiourea) were grown for single-crystal X-ray analysis and from the data it was observed that they organize into the P-1 space group. The thermal decomposition of these compounds has been studied by TG–DSC.

Synthesis and structural elucidation of a novel polymorph of alcaftadine.

In this study, we have synthesized and elucidated the structure of the H1 histamine antagonist, 2-(1-methylpiperidin-4-ylidene)-4,7-diazatricyclo[8.4.0.0((3,7))]tetradeca-1(14),3,5,10,12-pentaene-6-carbaldehyde in the solution and solid-state. We have also studied the thermal dilapidation of the compound. Solution structure analysis was achieved by employing NMR spectroscopy including 2D experiments NOESY, HSQC and HMBC, while solid state investigations were undertaken using SXRD, PXRD, TGA, DSC, and IR spectroscopy. For the first time the single crystal structure of alcaftadine has now been solved. Crystallographic data are as follows: monoclinic, Cc, a=11.5694(6)Å, b=14.5864(6)Å, c=10.2688(4)Å, α=90°, β=111.793(3)°, γ=90°, V=1609.07(13)Å(3), Z=4. The Hirshfeld surface analyses also have been performed using the crystal structure.

4,5,6,10,11,12,16,17,18,22,23,24-Dodeca-kis-[(meth-oxy-carbon-yl)meth-oxy]-2,8,14,20-tetra-pentyl-resorcin[4]arene.

The title compound, C84H112O36, has a macrocyclic structure. It has 12 (methoxycarbonyl)methoxy ‘head groups’ in the upper rim and exhibits a flattened boat geometry. Intramolecular C—H⋯O hydrogen bonds occur. In the crystal, intermolecular C—H⋯O contacts occur. The ‘head groups’ and the pentyl ‘feet’ contain disordered (0.5:0.5 occupancy ratio) atoms.

1,1'-(Propane-1,3-di-yl)bis-(3-phenyl-urea).

The title compound, C17H20N4O2, has crystallographic inversion symmetry. In the crystal structure, intermolecular hydrogen bonding between adjacent urea groups gives rise to infinite polymeric chains diagonally across the bc plane. With a centroid–centroid distance of 3.295 (2) Å, π–π stacking is present in the crystal along the same plane.

1,1'-(Ethane-1,2-di-yl)bis-(3-phenyl-thio-urea).

The complete molecule of the title compound, C16H18N4S2, is generated by crystallographic inversion symmetry. The dihedral angle between the phenyl ring and the thiourea group is 52.9 (4)°. The crystal structure displays intermolecular N—H⋯S hydrogen bonding, which generates sheets in the ab plane.

3,3′-Diphenyl-1,1′-(butane-1,4-di­yl)dithio­urea

The asymmetric unit of the title compound, C18H22N4S2, contains one half-molecule, the complete molecule being generated by crystallographic inversion symmetry. The crystal structure features two intermolecular N—H⋯S hydrogen-bonding interactions, the first generating an infinite chain along the b axis and the second an infinite chain along the a axis, together forming an interlocking structure.

Iridium and rhodium “PNP” aminodiphosphine complexes used as catalysts in the oxidation of styrene

Six PNP or aminodiphosphine ligands were synthesized and complexed to the transition metals iridium and rhodium to give [(η5-C5Me5)MCl{η2-P,P′-(PPh2)2NR}]PF6, where M = Ir (1) and Rh (2) and R = cyclohexyl (a), iso-propyl (b), pentyl (c), phenyl (d), chlorophenyl (e) and methoxyphenyl (f). These complexes were fully characterized by NMR, elemental analyses and IR spectroscopy. Crystals of 1f and 2f were obtained, which showed a distorted octahedral geometry around the metal centers. These complexes showed good activity in the oxidation of styrene using tert-butyl hydroperoxide (TBHP) as the oxidant. The iridium complexes were more active than the rhodium complexes. Higher yields for benzaldehyde were achieved in comparison to styrene oxide for all catalysts.

Physicochemical characterization and decomposition kinetics of (S)-4-[1-(2,3-dimethylphenyl)ethyl]-3H-imidazole HCl/S-enantiomer of medetomidineHCl

Abstract Physicochemical characterization of (S)-4-[1-(2,3-dimethylphenyl)ethyl]-3H-imidazole HCl in solution as well as the solid state has been done using single-crystal X-ray crystallography, 1H and 13C NMR, IR and mass spectrometry. The single-crystal structure, as well as Hirshfeld surface analysis, of the S-enantiomer is compared with the racemate, as well as the polymorph of the racemate. The decomposition kinetics of the S-enantiomer have been studied using thermogravimetric analysis and a differential scanning calorimetric investigation. The study was done to contribute to understanding the properties of the drug at a molecular level, thus providing tools to develop novel formulations of the drug.

Tetramethoxy resorcin[4]arene-tetraester derivatives

Structural elucidations of upper rim functionalized tetramethoxy resorcin[4] were achieved with FT-IR and 1H-13C-NMR spectroscopy. Further analysis was performed with both powder and single crystal X-ray diffraction. A thermal degradation of the three tetramethoxy resorcin[4]arenes was carried out by means of thermo gravimetry, and differential scanning calorimetry revealing that the nature of the derivatives “group” (aromatic or aliphatic) has a profound effect on their thermal properties. These compounds have excellent thermal stability.

6,12,18,24-Tetra­meth­oxy-4,10,16,22-tetra­kis­[(meth­oxy­carbon­yl)meth­oxy]-2,8,14,20-tetra­kis­(2-phenyl­eth­yl)resorcin[4]arene

The title compound, C76H80O16, is a macrocyclic structure. This novel resorcin[4]arene derivative has (methoxycarbonyl)methoxy ‘head’ groups on the upper rim. The compound has a C 2v ‘boat’ geometry and there are a range of C—H⋯O contacts in the crystal structure.