Thiazol-4-one derivatives from the reaction of monosubstituted thioureas with maleimides: structures and factors determining the selectivity and tautomeric equilibrium in solution

2-(Alkyl(aryl)amino)thiazol-4(5H)-ones can regioselectively be prepared from monoalkyl(aryl)thioureas and maleimides. In solution, the former heterocycles exist in a tautomeric equilibrium with 2-(alkyl(aryl)imino)thiazolidin-4-ones and the substituent on the exocyclic nitrogen atom governs the ratio of these tautomers. Isomers with the alkyl group in the endocyclic position can be obtained from N-methyl(ethyl)thioureas. 2D NMR spectroscopy and DFT calculations rationalize experimental results.

Les liaisons phosphore-azote via l'étude cristalline et moléculaire d'un iminodiazaphospholane

Iminodiazophospholane 1 was obtained as monoclinic crystals, space group P21/c with a = 10.243(9), b = 17.236(5), c = 11.992(9) Å, and Z = 4. The structure was determined by single-crystal X-ray diffraction and was refined up to R = 0.056[Formula: see text]for 1342 reflections. The geometry of the molecule is that of a distorted tetrahedron with [Formula: see text] angles varying from 91.8° (ring angle) to 121.7° for [Formula: see text]. The diazophospholane ring has an envelope conformation where one of the 2 carbon atoms is at the tip. The three tricoordinated nitrogen atoms have a planar structure; the lone pairs on the two ring nitrogens have parallel orientation and both are orthogonal to the lone pair of the exocyclic nitrogen atom (N7). The P—N bond lengths are relatively short, falling between 1.620 Å and 1.669 Å, while the P2=N6 bond of 1.539 Å is among the smallest values ever reported. The multiplicities of the P—N bonds were assigned on the basis of an empirical method: 0.10 for the two cyclic P—N, 0.25 for the exocyclic P—N, and 0.60 for [Formula: see text] [Journal translation]

Darstellung, Schwingungsspektren und Röntgenstrukturanalyse von Trifluor- und Trichloracetyltrischwefeltrinitrid, CX3CO-NS3N21 / Synthesis, Vibrational Spectra, and X-ray Structure Analysis of Trifluoro and Trichloroacetyl Trisulfurtrinitride, CX3CO—NS3N21

S4N4 reacts at 25 °C with trifluoro and trichloro acetic acid anhydride, respectively, to yield yellow crystalline CX3–CO–NS3N2 (X = F, Cl), the mass, infrared, and Raman spectra of which are reported. An X-ray structure analysis of monoclinic CF3CONS3N2 revealed a non-planar five-membered S3N2 ring containing an unusually long (2.206 A) sulfur-sulfur bond with one sulfur atom additionally connected to an exocyclic nitrogen atom by a multiple bond. Comparisons with the infrared spectra of S3N2O and ten compounds of type RNS3N2 allowed to identify four wavenumbers characteristic for the S3N2 ring. The relationship μ = 23.09d-27.27 has been derived for stretching vibrational wavelengths, μ (in μm), and bond distances, d (in Å), of sulfur-nitrogen bonds.