Efrén V. García-Báez

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Symmetric and non-symmetric 2-(N-H, N-methyl, N-ethylenyl and N-aryl)guanidinebenzothiazoles were synthesized from the reaction of ammonia, methylamine, pyrrolidine and aniline with dimethyl benzo[d]thiazol-2-yl-carbonodithioimidate as intermediate. The products were characterized by ¹H-, ¹³C-NMR spectroscopy and three of them by X-ray diffraction analysis.(More)
The title Schiff base compound, 4-nitro-1-oxo-2-{(E)-[2-(piperidin-1-yl)ethyl]iminiomethyl}cyclohexadienide, C(14)H(19)N(3)O(3), exists as a zwitterion, with the H atom of the phenol group being transferred to the imine N atom. The C=O, C(Ar)-C(Ar) and C-N bond lengths are in agreement with the oxocyclohexadienide-iminium zwitterionic form. The iminium H(More)
The thermal [4+2] cycloadditions of 3-acetyl-, 3-carbamoyl, and 3-ethoxycarbonylcoumarins with 2,3-dimethyl-1,3-butadiene under solvent free conditions are reported, as well as the epoxidation reactions of some adducts. Discussion is focused on the structural features of the Diels-Alder adducts and their epoxides, based upon NMR, X-ray, and mass spectral(More)
In the title complex salt, [Ir(C(5)H(4)O)(C(16)H(22)N(6))(CO)](CF(3)O(3)S), the Ir(III) centre adopts a distorted octahedral geometry with a facial coordination of the tris(3,5-dimethyl-1H-pyrazol-1-yl)methane ligand. The C-C distances of the iridacycle are in agreement with its iridacyclohexa-2,5-dien-4-one nature, which presents a nonsymmetric boat-like(More)
The title compounds, C(12)H(9)ClO(4), (I), and C(12)H(9)BrO(4), (II), are isomorphous and crystallize in the monoclinic space group P2(1)/c. Both compounds present an anti conformation between the 3-carboxy and the lactone carbonyl groups. Both carbonyl groups are out of the plane defined by the remaining chromene atoms, by 8.37 (6) and 17.57 (6) degrees(More)
Intramolecular hydrogen bond (HB) formation was analyzed in the model compounds N-(2-benzoylphenyl)acetamide, N-(2-benzoylphenyl)oxalamate and N1,N2-bis(2-benzoylphenyl)oxalamide. The formation of three-center hydrogen bonds in oxalyl derivatives was demonstrated in the solid state by the X-ray diffraction analysis of the geometric parameters associated(More)
In the title compound, C(16)H(18)N(4)O(2), the two carbonyl groups are in an anti-periplanar conformation with an O=C-C=O torsion angle of 173.86 (17)°. In the crystal, a pair of inter-molecular N-H⋯O hydrogen bonds, forming an R(2) (2)(10) ring motif, connect the mol-ecules into an inversion dimer. The dimers are further linked by N-H⋯N and C-H⋯π(More)
The title compound, C16H19NO5, crystallizes as a centrosymmetric dimer through strong O-H...O hydrogen-bonding interactions between the hydroxyphenyl and morpholinocarbonyl groups. The morpholinocarbonyl group is almost perpendicular to the propenoate moiety. Electron delocalization in the N-C(=O) fragment leads to the formation of hydrogen-bonded S(5) ring(More)
The title Schiff base compound, C(15)H(15)NO(2), crystallized as the iminium-phenolate zwitterion. The H atom is localized on the imine N atom, forming a strong intra-molecular hydrogen bond with the phenolate O atom, and giving rise to an S(6) ring motif. The mol-ecule has an E conformation about the C=N bond. In the crystal, mol-ecules are linked by O-H⋯O(More)