Diverse Cyclization Pathways Between Nitriles with Active -Methylene Group and Ambiphilic 2-Pyridylselenyl Reagents Enabled by Reversible Covalent Bonding.

Herein, we describe a novel coupling between ambiphilic 2-pyridylselenyl reagents and nitriles featuring an active α-methylene group. Depending on the solvent employed, this reaction can yield two distinct types of cationic pyridinium-fused selenium-containing heterocycles, 1,3-selenazolium or 1,2,4-selenadiazolium salts, in high yields. This is in contrast to what we observed before for other nitriles.

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

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

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.

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

1-Pyridine-2-selenenyl dibromide, CHNSeBr, , is a product of the bromination of bis-(pyridin-2-yl) diselenide in methyl-ene chloride recrystallization from methanol. Compound is essentially zwitterionic: the negative charge resides on the SeBr moiety and the positive charge is delocalized over the pyridinium fragment. The C-Se distance of 1.

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, CHClNOSe, 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.

Crystal structure of rac-(3aR*,9aS*)-4,4,4-tri-chloro-1,2,3,3a,4,9a-hexa-hydro-4λ(5),9λ(4)-cyclo-penta-[4,5][1,3]tellurazolo[3,2-a]pyridine.

The title compound, C10H12Cl3NTe, crystallizes with two crystallographically independent mol-ecules (A and B) in the asymmetric unit. In each case, the coordination around the Te atom is distorted square-pyramidal, with the equatorial plane composed of the three Cl atoms and the C atom of the pyridinium ring. The Te atom is displaced from the mean-square plane by 0.

Dichloridobis(pyridine-2-seleno-lato-κ(2) N,Se)tin(IV).

The title compound, [SnCl2(C5H4NSe)2], is the product of a reaction of 2,2'-dipyridyl diselenide with tin tetra-chloride. The mol-ecule is located about a twofold rotation axis. The coordination environment of the Sn(IV) atom is a distorted octa-hedron, with two bidentate 2-pyridine-seleno-late ligands inclined to each other at an angle of 83.

3-(4-Meth-oxy-phen-yl)-1,3-selenazolo[2,3-b][1,3]benzo-thia-zol-4-ium hydrogen sulfate.

The title compound, C16H12NOSSe(+)·HSO4 (-), was obtained from a mixture of 3-(4-meth-oxy-phen-yl)[1,3]selenazolo[2,3-b][1,3]benzo-thia-zol-4-ium chloride and potassium hydrogen sulfate. In the cation, the benzene ring is twisted by 71.62 (7)° from the tricycle mean plane.

[Bis(pyridin-2-yl) selenide-κ(2)N,N']tetra-chloridotin(IV).

The title compound, [SnCl(4)(C(10)H(8)N(2)Se)], was obtained by the reaction of 2,2'-dipyridyl diselenide with tin tetra-chloride. The Sn(IV) ion is coordinated by two N atoms [Sn-N = 2.266 (2) and 2.

Dichloridobis(pyridine-2-thiol-ato-κ²N,S)tin(IV): a new polymorph.

The title compound, [SnCl₂(C₅H₄NS)₂], is the product of reaction of 2,2'-dipyridyl disulfide with tin tetra-chloride. The Sn(IV) atom adopts a distorted octa-hedral geometry, with the two bidentate pyridine-2-thiol-ate ligands forming two planar four-membered chelate rings. The two Sn-Cl, two Sn-N and two Sn-S bonds are in cis, cis and trans configurations, respectively.

1-Methyl-2,3-dihydro-1H-benzimidazole-2-selone.

The title compound C(8)H(8)N(2)Se, is the product of the reaction of 2-chloro-1-methyl-benzimidazole with sodium hydro-selenide. The mol-ecule is almost planar (r.m.

1,3-Benzothia-zole-2(3H)-selone.

The title compound, C(7)H(5)NSSe, is the product of the reaction of 2-chloro-benzothia-zole with sodium hydro-selenide. The mol-ecule is almost planar (r.m.

(7aR*,12bS*)-8,12b-Dihydro-7aH-indeno-[1',2':5,6][1,4]selenazino[2,3,4-ij]quinolin-13-ium hydrogen sulfate.

In the title compound, C(18)H(14)NSe(+)·HSO(4) (-), the cyclo-pentene ring in the cation has an envelope conformation while the central six-membered 1,4-selenazine ring adopts a sofa conformation. The dihedral angle between the planes of the terminal benzene rings is 68.08 (11)°.