Adriano Bof de Oliveira

Haloacetylated enol ethers: 12 [18]. Regiospecific synthesis and structural determination of stable 5-hydroxy-1H-pyrazolines

Abstract The regiospecific synthesis and structural elucidation by NMR spectroscopy, AM1 semiempirical MO calculations and X-ray diffraction of a novel series of twelve 3-aryl[alkyl]-5-hydroxy-5-trichloromethyl-4, 5-dihydro-1H-pyrazole-1-carboxyamides and analogous 1-thiocarboxy-amides, is reported.

1-(5-Bromo-2-oxoindolin-3-yl-idene)thio-semicarbazide acetonitrile monosolvate.

In the crystal structure of the title compound, C9H7BrN4OS·C2H3N, the molecules are connected via N—H⋯O and N—H⋯S interactions into zigzag chains perpendicular to [001]. The molecules in these chains are additionally linked to acetonitrile solvent molecules through N—H⋯N hydrogen bonding. The molecules are arranged in layers and are stacked in the direction of the c axis indicative of π–π interactions, with distance = 3.381 (7) Å for the C⋯C interaction parallel to [001]. An intramolecular N—H⋯O hydrogen bond is also observed in the main molecule.

Molecular Structure of Heterocycles: 2 # NMR Spectroscopy, X- ray Diffraction, and Semiempirical MO Calculations of 5-Bromo-4, 6-dimethoxy-4-trichloromethyl-hexahydropyrimidin-2-one.

Abstract The structure of 5-Bromo-4, 6-dimethoxy-4-(trichloromethyl)hexahydro 2-pyrimidinone (3), synthesized from the reaction of 4-methoxy-4-(trichloromethyl)tetrahydro-2-pyrimidinone (2) with bromo and methanol, was determined by nmr spectroscopy, X-ray diffraction, and semiempirical MO calculations. 1H and 13C nmr data shown that only one pair of the diastereoisomers was obtained. The AM1 calculations showed that 3a is the more stable diastereoisomers pair. The x-ray diffraction data confirmed that only the structure 3a (4S5S6R/4R5R6S) of compound 3 was obtained. Compound 3a (C7H10BrCl3N2O3, Mr = 356.43) crystallizes in the orthorhombic space group P212121 with the unit cell dimensions a = 7.112(2), b = 14.719(2) and c = 12.084(3) A, R = 7.32 % and wR2 = 14.92 % for an F 2 refinement on unique data with 2931 reflections collected and 2248 independent (Rint = 4.01%), Flack parameter 0.00(3). #For Part 1, see Ref. 1.

4-Hydroxy-3-methoxybenzaldehyde 4-phenylthiosemicarbazone

In the title compound, C15H15N3O2S, the central C—N—N—C unit has an anti conformation [torsion angle = −170.17 (15)°]. The phenyl substituent is oriented perpendicular to this unit [dihedral angle of 89.2 (1)°], whereas the substituted ring is rotated out of this plane by only 18.86 (17)°. In the crystal, molecules are linked by pairs of N—H⋯S hydrogen bonds into inversion dimers that are further connected via N—H⋯O and O—H⋯S hydrogen bonds into a three-dimensional network.

Crystal structure of 4-hydroxy-3-meth-oxybenzaldehyde 4-methylthiosemi-carbazone methanol monosolvate

In the title solvate, C15H15N3O2S·CH3OH, the thiosemicarbazone molecule is approximately planar; the maximum deviation from the mean plane is 0.4659 (14) Å and the dihedral angle between the aromatic rings is 9.83 (8)°. This conformation is supported by an intramolecular N—H⋯N hydrogen bond. In the crystal, the thiosemicarbazone molecules are linked into dimers by pairs of N—H⋯S hydrogen bonds, thereby generating R 2 2(8) loops. The methanol solvent molecule bonds to the thiosemicarbazone molecule through a bifurcated O—H⋯(O,O) hydrogen bond and also accepts an O—H⋯O link from the thiosemicarbazone molecule. Together, these links generate a three-dimensional network.

Crystal structure of 4-hydroxy-3-methoxybenzaldehyde 4-methylthiosemicarbazone methanol monosolvate

In the title solvate, C15H15N3O2S·CH3OH, the thiosemicarbazone molecule is approximately planar; the maximum deviation from the mean plane is 0.4659 (14) Å and the dihedral angle between the aromatic rings is 9.83 (8)°. This conformation is supported by an intramolecular N—H⋯N hydrogen bond. In the crystal, the thiosemicarbazone molecules are linked into dimers by pairs of N—H⋯S hydrogen bonds, thereby generating R 2 2(8) loops. The methanol solvent molecule bonds to the thiosemicarbazone molecule through a bifurcated O—H⋯(O,O) hydrogen bond and also accepts an O—H⋯O link from the thiosemicarbazone molecule. Together, these links generate a three-dimensional network.