Facile Access to 2-Selenoxo-1,2,3,4-tetrahydro-4-quinazolinone Scaffolds and Corresponding Diselenides via Cyclization between Methyl Anthranilate and Isoselenocyanates: Synthesis and Structural Features.

A practical method for the synthesis of 2-selenoxo-1,2,3,4-tetrahydro-4-quinazolinone was reported. The latter compounds were found to undergo facile oxidation with H2O2 into corresponding diselenides. Novel organoselenium derivatives were characterized by the 1H, 77Se, and 13C NMR spectroscopies, high-resolution electrospray ionization mass spectrometry, IR, elemental analyses (C, H, N), and X-ray diffraction analysis for several of them. Novel heterocycles exhibited multiple remarkable chalcogen bonding (ChB) interactions in the solid state, which were studied theoretically.

Correction: Novel cationic 1,2,4-selenadiazoles: synthesis via addition of 2-pyridylselenyl halides to unactivated nitriles, structures and four-center Se⋯N contacts.

Correction for 'Novel cationic 1,2,4-selenadiazoles: synthesis via addition of 2-pyridylselenyl halides to unactivated nitriles, structures and four-center Se⋯N contacts' by Victor N. Khrustalev et al., Dalton Trans., 2021, 50, 10689-10691, DOI: 10.1039/D1DT01322J.

Crystal structure and Hirshfeld surface analysis of ethyl 6'-amino-2'-(chloro-meth-yl)-5'-cyano-2-oxo-1,2-di-hydro-spiro-[indoline-3,4'-pyran]-3'-carboxyl-ate.

The mol-ecular conformation of the title compound, C17H14ClN3O4, is stabilized by an intra-molecular C-H⋯O contact, forming an S(6) ring motif. In the crystal, the mol-ecules are connected by N-H⋯O hydrogen-bond pairs along the b-axis direction as dimers with R 2 2(8) and R 2 2(14) ring motifs and as ribbons formed by inter-molecular C-H⋯N hydrogen bonds. There are weak van der Waals inter-actions between the ribbons. The most important contributions to the surface contacts are from H⋯H (34.9%), O⋯H/H⋯O (19.2%), C⋯H/H⋯C (11.9%), Cl⋯H/H⋯Cl (10.7%) and N⋯H/H⋯N (10.4%) inter-actions, as concluded from a Hirshfeld surface analysis.

Novel cationic 1,2,4-selenadiazoles: synthesis via addition of 2-pyridylselenyl halides to unactivated nitriles, structures and four-center SeN contacts.

2-Pyridylselenyl halides undergo facile coupling with a triple CN bond of unactivated nitriles. Unprecedented heterocyclization allowed the preparation of a novel class of cationic 1,2,4-selenadiazoles in remarkably high yields. Cationic 1,2,4-selenadiazoles form supramolecular dimers in the crystal via SeN chalcogen bonding, which was studied theoretically.

Crystal structure and Hirshfeld surface analysis of 3-amino-1-oxo-2,6,8-triphenyl-1,2,7,8-tetra-hydro-iso-quinoline-4-carbo-nitrile.

In the title compound, C28H21N3O, the 1,2-di-hydro-pyridine ring of the 1,2,7,8-tetra-hydro-iso-quinoline ring system is planar as expected, while the cyclo-hexa-1,3-diene ring has a twist-boat conformation, with Cremer-Pople parameters Q T = 0.367 (2) A, θ = 117.3 (3)° and φ = 327.3 (4)°. The dihedral angles between the best planes through the iso-quinoline ring system and the three phenyl rings are 81.69 (12), 82.45 (11) and 47.36 (10)°. In the crystal, mol-ecules are linked via N-H⋯O and C-H⋯N hydrogen bonds, forming a three-dimensional network. Furthermore, the crystal packing is dominated by C-H⋯π bonds with a strong inter-action involving the phenyl H atoms. The role of the inter-molecular inter-actions in the crystal packing was clarified using Hirshfeld surface analysis, and two-dimensional fingerprint plots indicate that the most important contributions to the crystal packing are from H⋯H (46.0%), C⋯H/H⋯C (35.1%) and N⋯H/H⋯N (10.5%) contacts.

Crystal structure of 1,1'-{(1E,1'E)-[4,4'-(9H-fluorene-9,9-di-yl)bis-(4,1-phenyl-ene)]bis-(aza-nylyl-idene)bis(methanylyl-idene)}bis-(naphthalen-2-ol) di-chloro-benzene monosolvate.

The bis-(anil) mol-ecule of the title compound, C47H32N2O2·C6H4Cl2, contains two anil fragments in the enol-enol form, exhibiting intra-molecular O-H⋯N hydrogen bonds. The two hy-droxy-naphthalene ring systems are approximately parallel to each other with a dihedral angle of 4.67 (8)° between them, and each ring system makes a large dihedral angle [55.11 (11) and 48.50 (10)°] with the adjacent benzene ring. In the crystal, the bis-(anil) mol-ecules form an inversion dimer by a pair of weak C-H⋯O inter-actions. The dimers arrange in a one-dimensional column along the b axis via another C-H⋯O inter-action and a π-π stacking inter-action between the hy-droxy-naphthalene ring system with a centroid-centroid distance of 3.6562 (16) Å. The solvent 1,2-di-chloro-benzene mol-ecules are located between the dimers and bind neighbouring columns by weak C-H⋯Cl inter-actions. Theoretical prediction of potential biological activities was performed, which suggested that the title anil compound can exhibit histone de-acetyl-ase SIRT2, histone de-acetyl-ase class III and histone de-acetyl-ase SIRT1 activities, and will act as inhibitor to aspulvinone di-methyl-allyl-transferase, de-hydro-l-gulonate deca-rboxylase and gluta-thione thiol-esterase.

Bromination of bis-(pyridin-2-yl) diselenide in methyl-ene chloride: the reaction mechanism and crystal structures of 1H-pyridine-2-selenenyl dibromide and its cyclo-adduct with cyclo-pentene (3aSR,9aRS)-2,3,3a,9a-tetra-hydro-1H-cyclo-penta-[4,5][1,3]selenazolo[3,2-a]pyridinium bromide.

1H-Pyridine-2-selenenyl dibromide, C5H5NSeBr2, 1, is a product of the bromination of bis-(pyridin-2-yl) diselenide in methyl-ene chloride recrystallization from methanol. Compound 1 is essentially zwitterionic: the negative charge resides on the SeBr2 moiety and the positive charge is delocalized over the pyridinium fragment. The C-Se distance of 1.927 (3) Šis typical of a single bond. The virtually linear Br-Se-Br moiety of 178.428 (15)° has symmetrical geometry, with Se-Br bonds of 2.5761 (4) and 2.5920 (4) Å, and is twisted by 63.79 (8)° relative to the pyridinium plane. The Se atom forms an inter-molecular Se⋯Br contact of 3.4326 (4) Å, adopting a distorted square-planar coordination. In the crystal, mol-ecules of 1 are linked by inter-molecular N-H⋯Br and C-H⋯Br hydrogen bonds, as well as by non-covalent Se⋯Br inter-actions, into a three-dimensional framework. (3aSR,(9aRS)-2,3,3a,9a-Tetra-hydro-1H-cyclo-penta[4,5][1,3]selenazolo[3,2-a]pyridinium-9 bromide, C10H12NSe+·Br-, 2, is a product of the cyclo-addition reaction of 1 with cyclo-pentene. Compound 2 is a salt containing a selenazolopyridinium cation and a bromide anion. Both five-membered rings of the cation adopt envelope conformations. The dihedral angle between the basal planes of these rings is 62.45 (11)°. The Se atom of the cation forms two additional non-covalent inter-actions with the bromide anions at distances of 3.2715 (4) and 3.5683 (3) Å, attaining a distorted square-planar coordination. In the crystal, the cations and anions of 2 form centrosymmetric dimers by non-covalent Se⋯Br inter-actions. The dimers are linked by weak C-H⋯Br hydrogen bonds into double layers parallel to (001).

The synthesis and crystal structure of 2-(chloro-selan-yl)pyridine 1-oxide: the first monomeric organoselenenyl chloride stabilized by an intra-molecular secondary Se⋯O inter-action.

The title compound, C5H4ClNOSe, is the product of the reaction of sulfuryl chloride and 2-selanyl-1-pyridine 1-oxide in di-chloro-methane. The mol-ecule has an almost planar geometry (r.m.s. deviation = 0.012 Å), and its mol-ecular structure is stabilized by an intra-molecular secondary Se⋯O inter-action of 2.353 (3) Å, closing a four-membered N-C-Se⋯O ring. The title compound represents the first monomeric organoselenenyl chloride stabilized intra-molecularly by an inter-action of this type. The non-valent attractive Se⋯O inter-action results in a substantial distortion of the geometry of the ipso-carbon atom. The endo-cyclic N-C-Se [102.1 (3)°] and exo-cyclic C-C-Se [136.9 (3)°] bond angles deviate significantly from the ideal value of 120° for an sp2-hybridized carbon atom, the former bond angle being much smaller than the latter. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, forming zigzag chains propagating along [010]. The chains, which stack along the a-axis direction, are linked by offset π-π inter-actions [inter-centroid distance = 3.960 (3) Å], forming corrugated sheets parallel to the ab plane.