Amine exchange reactions of 3-<Emphasis Type="Italic">tert</Emphasis>-butyl-6-(methylsulfanyl)-1,2,3,4-tetrahydro-1,3,5-triazine hydroiodide with amino acids

3-tert-Butyl-6-(methylsulfanyl)-1,2,3,4-tetrahydro-1,3,5-triazine hydroiodide enters into the amine exchange reaction with glycine and β-alanine in aqueous solution. The final exchange products are [4-(methylsulfanyl)-5,6-dihydro-1,3,5-triazin-3-ium-1(2H)-yl] acetate and 3-[4-(methylsulfanyl)-5, 6-dihydro-1,3,5-triazin-3-ium-1(2H)-yl] propanoate, respectively, crystallizing together with t-butylamine hydroiodide from aqueous or aqueous alcoholic solutions as ion associates, which also can be detected in solution in DMSO-d ₆. [4-(Methylsulfanyl)-5,6-dihydro-1,3,5-triazin-3-ium-1(2H)-yl] acetate can be extracted directly from the reaction mixture after carrying out the amine exchange in aqueous isopropanol or 95% ethanol, as well as by “recrystallization“ of its associate with tert-butylamine hydroiodide from aqueous isopropanol.     

Mass spectra of new heterocycles: IX. Main fragmentaion laws of 7-methyl-2-(methylsulfanyl)-3-(1-ethoxyethoxy)-4,5-dihydro-3<Emphasis Type="Italic">H</Emphasis>-azepine and its structural isomers (2,3-dihydropyridine,pyrrole, thiophene) under electron impact

Mass spectra were investigated for the first time of four structural isomers of heterocycles, formerly inavailable 7-methyl-2-(methylsulfanyl)-3-(1-ethoxyethoxy)-4,5-dihydro-3H-azepine, 2,2-dimethyl-6-(methylsulfanyl)-5-(1-ethoxyethoxy)-2,3-dihydropyridine, 1-isopropyl-2-(methylsulfanyl)-3-(1-ethoxyethoxy)pyrrole, and N-isopropyl-N-methyl-3-(1-ethoxyethoxy)-2-thiophenamine prepared from a single linear precursor, adduct of α-lithiated 1-(1-ethoxyethoxy)allene and isopropyl isothiocyanate. All compounds formed a molecular ion (I _rel 1–6%) whose primary fragmentation at the electron impact (70 eV) occurs in two principal directions related to the cleavage of the C-O bonds in the 1-ethoxyethoxy-substituent: with a simple rupture of the bonds C-OEt and C-O(heterocycle) and with the elimination of an ethoxyethene molecule. In the spectra of 4,5-dihydro-3H-azepine and 2,3-dihydropyridine the first fragmentation channel of [M]^+· dominates. The second direction prevailes at the fragmentation of pyrrole and thiophene molecular ions leading to an odd-electrons ion with m/z 171. Further fragmentation of this ion is characteristic of each isomer and resulted in the formation of diagnostic ions providing a possibility of identification of these isomers by mass spectrometry.     

基于含有硫醚基团的吡啶烷基酰胺配体的铜配合物的合成和结构表征

合成和表征了含有硫醚基团的吡啶烷基酰胺配体2-(甲硫基)-N-[2-(2-吡啶)甲基]乙酰胺(HL1)和2-(甲硫基)-N-[2-(2-吡啶)乙基]乙酰胺(HL2)及其3个铜的配合物,{[Cu(L1)(CH₃OH)](OTf)}_n(1)(Otf=三氟甲磺酸根),{[Cu(L2)(OTf)]·CH₃OH}_n(2)和[Cu(HL2)(CH₃OH)Cl](3),并通过X-射线单晶衍射分析确定了其晶体结构。配合物1和2均为含有铜的一维配位聚合物,而配合物3为单核铜配合物。分析了配合物中铜离子的配位特点及可能的形成原因。     

基于含有硫醚基团的吡啶烷基酰胺配体的铜配合物的合成和结构表征

合成和表征了含有硫醚基团的吡啶烷基酰胺配体2-(甲硫基)-N-[2-(2-吡啶)甲基]乙酰胺(HL1)和2-(甲硫基)-N-[2-(2-吡啶)乙基]乙酰胺(HL2)及其3个铜的配合物,{[Cu(L1)(CH₃OH)](OTf)}_n(1)(Otf=三氟甲磺酸根),{[Cu(L2)(OTf)]·CH₃OH}_n(2)和[Cu(HL2)(CH₃OH)Cl](3),并通过X-射线单晶衍射分析确定了其晶体结构。配合物1和2均为含有铜的一维配位聚合物,而配合物3为单核铜配合物。分析了配合物中铜离子的配位特点及可能的形成原因。     

Monodentate and bridging behaviour of the sulfur‐containing ligand 4′‐[4‐(methylsulfanyl)phenyl]‐4,2′:6′,4′′‐terpyridine in two discrete zinc(II) complexes with acetylacetonate

The Zn complexes bis(acetylacetonato‐κ²O,O′)bis{4′‐[4‐(methylsulfanyl)phenyl]‐4,2′:6′,4′′‐terpyridine‐κN¹}zinc(II), [Zn(C₅H₇O₂)₂(C₂₂H₁₇N₃S)₂], (I), and {μ‐4′‐[4‐(methylsulfanyl)phenyl]‐4,2′:6′,4′′‐terpyridine‐κ²N¹:N^1′′}bis[bis(acetylacetonato‐κ²O,O′)zinc(II)], [Zn₂(C₅H₇O₂)₄(C₂₂H₁₇N₃S)], (II), are discrete entities with different nuclearities. Compound (I) consists of two centrosymmetrically related monodentate 4′‐[4‐(methylsulfanyl)phenyl]‐4,2′:6′,4′′‐terpyridine (L1) ligands binding to one Zn^II atom sitting on an inversion centre and two centrosymmetrically related chelating acetylacetonate (acac) groups which bind via carbonyl O‐atom donors, giving an N₂O₄ octahedral environment for Zn^II. Compound (II), however, consists of a bis‐monodentate L1 ligand bridging two Zn^II atoms from two different Zn(acac)₂ fragments. Intra‐ and intermolecular interactions are weak, mainly of the C—H...π and π–π types, mediating similar layered structures. In contrast to related structures in the literature, sulfur‐mediated nonbonding interactions in (II) do not seem to have any significant influence on the supramolecular structure.     

Three 2‐(methysulfanyl)nicotinamides

The molecular conformations of three N‐alkyl‐2‐(methylsulfanyl)nicotinamide derivatives, namely N‐cyclohexyl‐2‐(methylsulfanyl)nicotinamide, C₁₃H₁₈N₂OS, (I), N‐isopropyl‐2‐(methylsulfanyl)nicotinamide, C₁₀H₁₄N₂OS, (II), in which there are two molecules in the asymmetric unit which were chosen to form a hydrogen‐bonded pair, and N‐(2‐hydroxyethyl)‐2‐(methylsulfanyl)nicotinamide dihydrate, C₉H₁₂N₂O₂S·2H₂O, (III), are compared with those of four unsubstituted N‐alkylnicotinamide compounds. The substituted compounds show a higher degree of torsion of the pyridine ring with respect to the amide group than do the unsubstituted compounds, with dihedral angles in the range 40–60° for the former and 20–35° for the latter. In (I) and (II), the supramolecular structure is defined by amide‐N to carbonyl‐O chains. In (III), the nicotinamide molecules are linked by hydrogen bonds to two water molecules resulting in two linked chains of rings which form the three‐dimensional network.     

A sulfur coordination polymer with wide bandgap semiconductivity formed from zinc(II) and 5‐methylsulfanyl‐1,3,4‐thiadiazole‐2‐thione

The sulfur coordination polymer catena‐poly[zinc(II)‐μ₂‐bis[5‐(methylsulfanyl)‐2‐sulfanylidene‐2,3‐dihydro‐1,3,4‐thiadiazol‐3‐ido‐κ²N³:S]], [Zn(C₃H₃N₂S₃)₂]_n or [Zn₂MTT₄]_n, constructed from Zn²⁺ ions and 5‐methylsulfanyl‐1,3,4‐thiadiazole‐2‐thione (HMTT), was synthesized successfully and structurally characterized. [Zn₂MTT₄]_n crystallizes in the tetragonal space group I (No. 82). Each MTT^? ligand (systematic name: 5‐methylsulfanyl‐2‐sulfanylidene‐2,3‐dihydro‐1,3,4‐thiadiazol‐3‐ide) coordinates to two different Zn^II ions, one via the thione group and the other via a ring N atom, with one Zn^II atom being in a tetrahedral ZnS₄ and the other in a tetrahedral ZnN₄ coordination environment. These tetrahedral ZnS₄ and ZnN₄ units are alternately linked by the organic ligands, forming a one‐dimensional chain structure along the c axis. The one‐dimensional chains are further linked via C—H…N and C—H…S hydrogen bonds to form a three‐dimensional network adopting an ABAB‐style arrangement that lies along both the a and b axes. The three‐dimensional Hirshfeld surface analysis and two‐dimensional (2D) fingerprint plots confirm the major interactions as C—H…S hydrogen bonds with a total of 35.1%, while 7.4% are C—H…N hydrogen‐bond interactions. [Zn₂MTT₄]_n possesses high thermal and chemical stability and a linear temperature dependence of the bandgap from room temperature to 270 °C. Further investigation revealed that the bandgap changes sharply in ammonia, but only fluctuates slightly in other solvents, indicating its promising application as a selective sensor.     

Synthesis of 5‐Aryl‐3‐(methylsulfanyl)‐1H‐pyrazoles via Three‐Component Reaction of 1,1‐Bis(methylsulfanyl)‐2‐nitroethene,Aromatic Aldehydes,and Hydrazine

An efficient approach for the preparation of functionalized 5‐aryl‐3‐(methylsulfanyl)‐1H‐pyrazoles 2 is described. This three‐component reaction between benzaldehydes 1 , NH₂NH₂?H₂O, and 1,1‐bis(methylsulfanyl)‐2‐nitroethene proceeds in EtOH under reflux conditions in good‐to‐excellent yields. The structures of 2 were corroborated spectroscopically (IR, ¹H‐ and ¹³C‐NMR, and EI‐MS). A plausible mechanism for this type of reaction is proposed (Scheme 2).     

Catalyst‐ and solvent‐free synthesis of 2‐fluoro‐N‐(3‐methylsulfanyl‐1H‐1,2,4‐triazol‐5‐yl)benzamide through a microwave‐assisted Fries rearrangement: X‐ray structural and theoretical studies

An efficient approach for the regioselective synthesis of (5‐amino‐3‐methylsulfanyl‐1H‐1,2,4‐triazol‐1‐yl)(2‐fluorophenyl)methanone, C₁₀H₉FN₄OS, (3), from the N‐acylation of 3‐amino‐5‐methylsulfanyl‐1H‐1,2,4‐triazole, (1), with 2‐fluorobenzoyl chloride has been developed. Heterocyclic amide (3) was used successfully as a strategic intermediate for the preparation of 2‐fluoro‐N‐(3‐methylsulfanyl‐1H‐1,2,4‐triazol‐5‐yl)benzamide, C₁₀H₉FN₄OS, (4), through a microwave‐assisted Fries rearrangement under catalyst‐ and solvent‐free conditions. Theoretical studies of the prototropy process of (1) and the Fries rearrangement of (3) to provide (4), involving the formation of an intimate ion pair as the key step, were carried out by density functional theory (DFT) calculations. The crystallographic analysis of the intermolecular interactions and the energy frameworks based on the effects of the different molecular conformations of (3) and (4) are described.     

A new tetrathiafulvalene–diamide cation salt with [Cu2Br4]2− anions

The title salt, bis[2,3‐bis(aminocarbonyl)‐8,9‐bis(methylsulfanyl)tetrathiafulvalenium] di‐μ‐bromido‐bis[bromidocopper(II)], (C₁₀H₁₀N₂O₂S₆)₂[Cu₂Br₄], contains 2,3‐bis(aminocarbonyl)‐8,9‐bis(methylsulfanyl)tetrathiafulvalenium radical cations, [DMT‐TTF(CONH₂)₂]^·+, and [Cu₂Br₄]²⁻ anions. The cations are associated across centres of inversion in a head‐to‐tail fashion via short face‐to‐face S...S stacking (TTF moiety). These dimers are further assembled into a one‐dimensional chain structure via interdimer double S...S contacts involving the methylsulfanyl groups. The one‐dimensional chains give rise to a two‐dimensional structure through intermolecular double N—H...O hydrogen bonds involving the amide group. The [Cu₂Br₄]²⁻ anions, which straddle centres of inversion, are located between the cation layers. Electron paramagnetic resonance measurements show a radical signal, indicating that the two TTF^·+ radicals are not completely coupled in the dimer.     

Synthesis and intramolecular cyclization of 2‐methylsulfany‐4‐oxo‐3(4H)‐quinazolinyl)acetohydrazide

Treatment of ambident sodium salt of 2‐methylsulfanyl‐4(3H)‐quinazolinone with methyl bromoacetate resulted in N₍₃₎‐alkyl ester formation. Reaction of the resulted ester with hydrazine hydrate gave 2‐methylsulfanyl‐4‐oxo‐3(4H)‐quinazolinyl)acetohydrazide, which underwent intramolecular cyclization under heating in dimethylformamide to give 1‐aminoimidazo[2,1‐b]quinazoline‐2,5(1H,3H)‐dione. The latter took place in acylation reaction and in condensation with aromatic aldehydes.     

Planarity of benzoyldithiocarbazate tuberculostatics. II. Diesters of benzoyldithiocarbazic acid

The emergence of drug‐resistant strains of Mycobacterium tuberculosis has intensified efforts to identify new lead tuberculostatics. Our earlier studies concluded that the planarity of a molecule correlates well with its tuberculostatic activity. According to our hypothesis, only derivatives whose molecules are capable of adopting a planar conformation may show tuberculostatic activity. The structures of three new potentially tuberculostatic compounds, namely N′‐[bis(methylsulfanyl)methylidene]‐N‐methyl‐4‐nitrobenzohydrazide (denoted G1), C₁₁H₁₃N₃O₃S₂, N′‐[bis(benzylsulfanyl)methylidene]‐N‐methyl‐4‐nitrobenzohydrazide (denoted G2), C₂₃H₂₁N₃O₃S₂, and N′‐[(benzylsulfanyl)(methylsulfanyl)methylidene]‐4‐nitrobenzohydrazide (denoted G3), C₁₆H₁₅N₃O₃S₂, were determined by X‐ray diffraction. The significant distortion from planarity caused by the methyl substituent at the N atom of the hydrazide group or the NO₂ substituent in the aromatic ring leads to the loss of tuberculostatic activity for G1, G2 and G4 {systematic name: N′‐[bis(methylsulfanyl)methylidene]‐2‐nitrobenzohydrazide}. A similar effect is observed when there are large substituents at the S atoms (G2 and G3).     

Regioselectivity of heterocyclization of 2-substituted 3,3-bis(methylsulfanyl)acrylo-nitriles with 2-benzimidazoleacetonitrile

Functionalized pyrido[1,2-a]benzimidazoles have been synthesized by the interaction of 2-substituted 2-cyano-3,3-bis(methylsulfanyl)acrylonitriles with 2-benzimidazoleacetonitrile under S _N Vin reaction conditions.     

A monomeric gold(I) carbanion complex with an uncoordinated thioether: [2‐(methylsulfanyl)phenyl](triphenylphosphine)gold(I)

The title compound, [Au(C₇H₇S)(C₁₈H₁₅P)], is conformationally chiral and crystallizes from benzene–hexane as individually enantiopure crystals. This mononuclear compound has the Au^I atom linearly bound to a triphenylphosphine P atom and to a phenyl C atom of a 2‐(methylsulfanyl)phenyl group. The angle at the Au^I atom is 175.9 (2)°. The linear ligand coordination about the Au^I atom has geometric parameters inside the remarkably narrow range found for gold complexes bound by a phosphine ligand and by the ortho‐C atom of a substituted phenyl group. This is the first example of gold(I) attached to a methylsulfanyl aromatic carbanion.     

Folded conformations due to arene interactions in dissymmetric and symmetric butylidene‐linker models based on pyrazolo[3,4‐d]pyrimidine,purine and 7‐deazapurine

The butylidene‐linker models 1‐[2‐(2,6‐dimethylsulfanyl‐9H‐purin‐9‐yl)‐2‐methylidenepropyl]‐4,6‐bis(methylsulfanyl)‐1H‐pyrazolo[3,4‐d]pyrimidine, C₁₈H₂₀N₈S₄, (XI), 7,7′‐(2‐methylidenepropane‐1,3‐diyl)bis[3‐methyl‐2‐methylsulfanyl‐3H‐pyrrolo[2,3‐d]pyrimidin‐4(7H)‐one], C₂₀H₂₂N₆O₂S₂, (XIV), and 7‐[2‐(4,6‐dimethylsulfanyl‐1H‐pyrazolo[3,4‐d]pyrimidin‐1‐yl)‐2‐methylidenepropyl]‐3‐methyl‐2‐methylsulfanyl‐3H‐pyrrolo[2,3‐d]pyrimidin‐4(7H)‐one, C₁₉H₂₁N₇OS₃, (XV), show folded conformations in solution, as shown by ¹H NMR analysis. This folding carries over to the crystalline state. Intramolecular π–π interactions are observed in all three compounds, but only (XIV) shows additional intramolecular C—H...π interactions in the solid state. As far as can be established, this is the first report incorporating the pyrrolo[2,3‐d]pyrimidine nucleus for such a study. In addition to the π–π interactions, the crystal structures are also stabilized by other weak intermolecular C—H...S/N/O and/or S...N/S interactions.     

Decoupled Spin Crossover and Structural Phase Transition in a Molecular Iron(II) Complex

Crystalline [Fe(bppSMe)₂][BF₄]₂ ( 1 ; bppSMe=4‐(methylsulfanyl)‐2,6‐di(pyrazol‐1‐yl)pyridine) undergoes an abrupt spin‐crossover (SCO) event at 265±5 K. The crystals also undergo a separate phase transition near 205 K, involving a contraction of the unit‐cell a axis to one‐third of its original value (high‐temperature phase 1; Pbcn, Z=12; low‐temperature phase 2; Pbcn, Z=4). The SCO‐active phase 1 contains two unique molecular environments, one of which appears to undergo SCO more gradually than the other. In contrast, powder samples of 1 retain phase 1 between 140–300 K, although their SCO behaviour is essentially identical to the single crystals. The compounds [Fe(bppBr)₂][BF₄]₂ ( 2 ; bppBr=4‐bromo‐2,6‐di(pyrazol‐1‐yl)pyridine) and [Fe(bppI)₂][BF₄]₂ ( 3 ; bppI=4‐iodo‐2,6‐di(pyrazol‐1‐yl)‐pyridine) exhibit more gradual SCO near room temperature, and adopt phase 2 in both spin states. Comparison of 1 – 3 reveals that the more cooperative spin transition in 1 , and its separate crystallographic phase transition, can both be attributed to an intermolecular steric interaction involving the methylsulfanyl substituents. All three compounds exhibit the light‐induced excited‐spin‐state trapping (LIESST) effect with T(LIESST=70–80 K), but show complicated LIESST relaxation kinetics involving both weakly cooperative (exponential) and strongly cooperative (sigmoidal) components.     

Insertion of Elemental Sulfur into the Se-Se Bond of Diorganyl Diselenides. Synthesis of Bis-alkyl(seleno) Polysulfides

Reaction of dialkyl diselenides R₂Se₂ (R = Me, n-Bu) with sulfur at room temperature in the presence of the catalytic system DMSO-Na₂S·9H₂O-triethylbenzylammonium chloride, as well as at 55-60°C in the presence or in the absence of catalysts leads to the insertion of from one to six atoms of sulfur into the Se-Se bond. Bis(methylseleno) polysulfides MeSeS_nSeMe with n = 5-6 gradually liberate sulfur on keeping. Dibutyl diselenide is less active than dimethyl diselenide, and diphenyl diselenide does not react with sulfur in boiling carbon disulfide. At 55-60°C a small portion of selenium in dialkyl diselenides passes into unreacted sulfur which is indicative of cleavage of the C-Se bonds in bis(methylseleno) polysulfides.     

Coordination Behavior of Sterically Protected Phosphaalkenes on the AuCl Moiety Leading to Catalytic 1,6‐Enyne Cycloisomerization

Mes*‐substituted 2,3‐dimethyl‐1,4‐diphosphabuta‐1,3‐diene, 1,2‐diphenyl‐3,4‐diphosphinidenecyclobutene, 2,2‐bis(methylsulfanyl)‐1‐phosphaethene, and 3,3‐diphenyl‐1,3‐diphosphapropenes (Mes*=2,4,6‐tri‐tert‐butylphenyl) were employed as P ligands of gold(I) complexes. The (E,E)‐2,3‐dimethyl‐1,4‐diphosphabuta‐1,3‐diene functioned as a P2 ligand for digold(I) complex formation with or without intramolecular Au–Au contact, which depends on the conformation of the 1,3‐diphosphabuta‐1,3‐diene. The 1,2‐diphenyl‐3,4‐diphosphinidenecyclobutene, which has a rigid s‐cis P?C? C?P skeleton, afforded the corresponding digold(I) complexes with a slight distortion of the planar diphosphinidenecyclobutene framework and intramolecular Au–Au contact. In the case of the 2,2‐bis(methylsulfanyl)‐1‐phosphaethene, only the phosphorus atom coordinated to gold, and the sulfur atom showed almost no intra‐ or intermolecular coordination to gold. On the other hand, the 1,3‐diphosphapropenes behaved as nonequivalent P2 ligands to afford the corresponding mono‐ and digold(I) complexes. Some phosphaalkene–gold(I) complexes showed catalytic activity for 1,6‐enyne cycloisomerization without cocatalysts such as silver hexafluoroantimonate.     

Synthesis,Crystal Structure and Magnetism of the New Oxysulfide Ce3NbO4S3

The orange cerium‐niobium‐oxysulfide Ce₃NbO₄S₃ was synthesized by the solid state reaction of CeO₂, Ce‐metal, Nb₂O₅ and sulfur at 1100 °C. The crystal structure has orthorhombic symmetry (space group Pbam, a = 7.055(1), b = 14.571(3), c = 7.627(2) Å, Z = 4) and contains isolated [Nb₂S₄O₆]¹⁰⁻ ions consisting of two strongly distorted, edge sharing NbO₃SS_2/2 octahedra. Niobium is connected to three oxygen and three sulfur atoms. The cerium atoms are eightfold coordinated by oxygen and sulfur atoms. Certain oxygen and sulfur atoms are not connected to niobium, but exclusively surrounded by cerium. By connecting these cation polyhedra, one recognizes layers of polycations perpendicular to the c‐axis. The magnetic susceptibility shows Curie‐Weiss behavior with an effective magnetic moment μ_eff = 2.63(1) μ_B/Ce in agreement with Ce³⁺. A Weiss‐constant θ_p = –12(1) K indicates weak antiferromagnetic coupling. No magnetic ordering was detected above 2 K.     

Planarity of heteroaryldithiocarbazic acid derivatives showing tuberculostatic activity. III. Mono‐ and diesters of 3‐(pyrazin‐2‐ylcarbonyl)dithiocarbazic acid

Methyl 2‐(pyrazin‐2‐ylcarbonyl)hydrazinecarbodithioate, C₇H₈N₄OS₂, (E1), N′‐[bis(methylsulfanyl)methylidene]pyrazine‐2‐carbohydrazide, C₈H₁₀N₄OS₂, (F1), N′‐[bis(methylsulfanyl)methylidene]‐6‐methoxypyrazine‐2‐carbohydrazide, C₉H₁₂N₄O₂S₂, (F2), and methyl 1‐methyl‐2‐(pyrazin‐2‐ylcarbonyl)hydrazinecarbodithioate, C₈H₁₀N₄OS₂, (G1), can be considered as derivatives of classical (thio)amide‐type tuberculostatics, and all are moderately active against Mycobacterium tuberculosis. This study was undertaken in a search for relationships between activity and specific intramolecular interactions, especially conjugations and hydrogen‐bond contacts, and the molecular structures were compared with respective amine analogues, also active against the pathogen. Despite the differences between the amine and carbonyl groups with opposite functions in the hydrogen bond, the two types of structure show a surprisingly similar planar geometry, mostly due to the conjugations aided by the bifurcated intramolecular hydrogen‐bond contact between the N—H group of the central hydrazide group as donor and a pyrazine N atom and an S atom of the dithio function as acceptors. Planarity was suggested to be crucial for the tuberculostatic activity of these compounds. The N‐methylated derivative (G1) showed a significant twist at the N—N bond [torsion angle = −121.9 (3)°] due to the methyl substitution, which precludes an intramolecular N—H...S contact and the planarity of the whole molecule. Nonetheless, the compound shows moderate tuberculostatic activity.