Center for Magnetic Resonance

Alena S. Pankova, Mikhail A. Kuznetsov

“Synthesis and thermal transformations of spiro-fused N-phthalimidoaziridines”

Tetrahedron Letters, 2014, In Press

DOI: 10.1016/j.tetlet.2014.03.014

Oxidation of N-aminophthalimide in the presence of 2-arylideneinden-1,3-diones with electron-withdrawing substituents gives the corresponding 3-aryl-1-phthalimidospiro[aziridine-2,2’-indene]-1’,3’-diones in good yields. Heating these aziridines with standard dipolarophiles (N-phenylmaleimide, dimethyl acetylenedicarboxylate, maleate and fumarate) leads, in most cases, to spiro[inden-2,2’-pyrrole] derivatives as products of 1,3-dipolar cycloaddition of the intermediate azomethine ylides with up to 70-95% yields in the case of N-phenylmaleimide. As is typical for 2-acylaziridines, the competing rearrangement into 2-aryl-4H-indeno[2,1-d][1,3]oxazol-4-ones prevails for less active dipolarophiles. Increasing the electron-releasing properties of the 3-aryl ring allows the observation of the push-pull effect of electron-donating and electron-withdrawing substituents on the ease of the three-membered ring-opening.

M. A. Kuznetsov, A. Ya. Bespalov

“One-pot, Three-component Synthesis of [1,3]thiazolo[4,3-b][1,3,4]thiadiazoles: Correct Structure of the Products”

Chem. Heterocycl. Compd., 2014, 49, 1458-1463

DOI: 10.1007/s10593-014-1396-4

The products of the one-pot, three-component synthesis of [1,3]thiazolo-[4,3-b][1, 3, 4]thiadiazoles from aromatic aldehydes, thioglycolic acid, and compounds containing a C(=S)–N–NH2 fragment (thiosemicarbazide or 4-amino-2,4-dihydro-3H-1,2,4-triazole-3-thiones) are not condensed hetero-cycles (as reported by several researchers), but are thiosemicarbazones or triazolylimines of the aldehydes used.

Julia R. Shakirova, Elena V. Grachova, Antti J. Karttunen, Vladislav V. Gurzhiy, Sergey P. Tunik and Igor O. Koshevoy

“Metallophilicity-assisted assembly of phosphine-based cage molecules”

Dalton Trans., 2014, Advance Article

DOI: 10.1039/c3dt53645a

A family of supramolecular cage molecules has been obtained via self-assembly of the phosphine–gold coordination complexes following an aurophilicity-driven aggregation approach. Use of the di- (PP) or tridentate (PPP) phosphine ligands P_n (n = 2, 3) with rigid polyaromatic backbones leads to clean formation of the coordination P_n(Au(tht))_nⁿ⁺ species, sequential treatment of which with H₂O/NEt₃ and excess of H₂NBu^t gives the finite 3D structures of two major types. The cylindrical-like hexametallic cages [(PPAu₂)₃(μ₃-NBu^t)₂]²⁺ are based on the diphosphines PP = 1,4-bis(diphenylphosphino)benzene (1), 4,4′-bis(diphenylphosphino)biphenyl (2), 4,4′′-bis(diphenylphosphino)terphenyl (3), while the triphosphine PPP (1,3,5-tris(diphenylphosphinophenyl)benzene) produces a tetrahedral dodecagold complex [(PPPAu₃)₄(μ₃-NBu^t)₄]⁴⁺ (4). The cages 1–4 have been studied using the ESI-MS and ¹H, ³¹P NMR spectroscopy, and the crystal structures of 1 and 4 were determined by an X-ray diffraction study. The NMR spectroscopic investigations showed that cylindrical complexes 1–3 undergo twisting-like interconversion of the helical P↔M isomers in solution, while 4 is a stereochemically rigid compound retaining its axially chiral architecture. The difference in dynamic behaviour was rationalized using computational studies with density functional methods.