Action of nitrous acid on some methylpyrimidines

Mono-organotin(IV) and tin(IV) derivatives of 2-mercaptopyridine and 2-mercaptopyrimidine: X-ray structures of methyl-tris(2-pyridinethiolato)tin(IV) and phenyl-tris(2-pyridinethiolato)tin(IV)�1.5CHCl3

“…2), where SPy acts as a bidentate ligand coordinating Sn through chelation by S and N atoms, according to point-charge model rationalization of the 119 Sn nuclear quadrupole splitting ⌬E, holds for the RSnL 3 complexes investigated here in the solid state, except for benzyltin and o-aryltin compounds which are octahedral instead of pentagonal bipyramidal. By the same procedure, analogous coordination modes are inferred for octahedral RSnClL 2 and trigonal bipyramidal RSnCl 2 L. The solid-state monomeric species (according also to the dynamics of 119 Sn nuclei determined for representative terms 2 ) persist in CDCl 3 and CHCl 3 , as well as in DMSO for some RSnL 3 complexes selected as examples; according to IR and 1 H, 13 C and 119 Sn NMR spectroscopic data, ligands SPy and SPym act as chelating agents in solution phases, and RSn(IV) complexes mainly maintain the solid-state structure also in solution.…”

“…The molecular weights of 1, 5, 10, 13, 15 and 17 in DMSO solution were found to be 222, 259, 208, 219, 259 and 290, respectively; these values would indicate dissociation. Since the measurements of the solutions in DMSO were made for technical reasons at 90°C, and since 1 H, 13 C and 119 Sn NMR spectra of the compounds (vide infra) obtained at room temperature indicate the presence of monomeric species, it is assumed that dissociation occurs only at higher temperatures.…”

“…10-12. PymS-SPym was synthesized according to Ref. 13; PyS-SPy was obtained analogously. HSPy and HSPym were products of Fluka Chemie AG; other reactants and solvents were commercial products and were purified and dried as usual.…”

“…24, a coordination number greater than four is suggested for tin. From the 13 C NMR shift values it was concluded that the SPy ligands are equivalent, or are made equivalent by an averaging process. 24 Since tin in solid 23 was found to be hexacoordinated, 24 and considering the observation that tin in organotin mercaptopyridine compounds, whose solid-state structure is known, generally retains its coordination number in non-coordinating solvents, it seems reasonable to propose that in 23 tin has formally a coordination number of six.…”

Oximes of six-membered heterocyclic compounds with two or three hetero-atoms: I. Synthesis and structure (review)

“…In the reaction of 4,5-dimethylpyrimidine 16 with EtONO only the activated methyl group at position 4 is nitrosated, and this leads to the formation of 5-methylpyrimidine-4-aldoxime 17 as the only product [27]. However, the reaction of 1,4,6-trimethylpyrimidin-2-one 18 with an excess of sodium nitrite gives 4,6-bis(hydroxyiminomethyl)-1-methylpyrimidine 19 with a yield of 75% [28]. The reaction of the ketone 20 with sodium nitrite in a water-dioxane solution of HCl gives the α-keto oxime 21 with an 86% yield.…”