Transition metal complexes of N-1-tosylcytosine and N-1-mesylcytosine

The syntheses as well as chemical and X-ray structural characterization of dichlorobis[1-(p-toluenesulfonyl)cytosine]copper(II) (2), its solvated pseudopolymorph containing two methanol molecules (3), dichlorobis[1-(p-toluenesulfonyl)cytosine]cadmium(II) (4), 1-methanesulfonylcytosine (6) and its copper complex dichlorobis(1-methanesulfonylcytosine)copper(II) (7) are described. In addition, spectroscopic studies of dichlorobis[1-(p-toluenesulfonyl)cytosine]cobalt(II) (5), as well as of dichlorobis(1-mesylcytosine)cadmium(II) (8) are presented. Pseudopolymorphs 2 and 3, as well as their 1-mesylcytosine analog 7, reveal square-planar coordination spheres, almost ideal in the case of 2, but considerably distorted in the case of 3 and 7. In all cases, the Cu(II) ion is coordinated by two endocyclic N3 atoms from two ligand molecules and by two chlorine atoms. The analogous coordination sphere was found in complex 4, where Cd(II) lies in the center of a slightly distorted tetrahedron formed by two endocyclic N3 atoms and by two chlorine atoms.     

Synthesis and aminolysis of N-(4-chlorophenyl)- and N-(2,4-dichlorophenylsulfonyl)-N-(glycidyl)bicyclo-[2.2.1]hept-5-en-endo-ylmethylamines

A glycidyl fragment was introduced into molecules of derivatives of bicyclo[2.2.1]hept-5-en-endo-2-ylmethylamine (sulfonamides, sulfonylurea) under the conditions of phase-transfer catalysis; carboxamides were established to be passive in this reaction; the results were compared with the calculations of the proton affinity of the nitrogen atoms in the molecules of the acyl derivatives of the framework amine. Products were obtained from reactions of N-(4-chlorophenylsulfonyl)-N-(glycidyl)bicyclo[2.2.1]hept-5-en-endo-2-ylmethylamine with benzylamine, N-benzylpiperazine, and bicyclic framework amines. The regiochemistry of the aminolysis was investiganted with the help of NMR ¹H, ¹³C spectra, and also with the use of 2D spectra COSY, NOESY, HMQC, HMBC.     

N-(p-methoxyphenyl)-N-prop-2-ynyl-urea: a crystal structure with the rare Z′=5, and statistical data on Z′ values

The crystal structure of N-(p-methoxyphenyl)-N-prop-2-ynyl-urea contains five symmetry-independent molecules (Z′=5), which is a high and rarely occurring value. The five molecules have similar but not identical conformations, and form similar but not identical intermolecular interactions. The terminal alkyne groups of the five molecules are oriented differently, and form different hydrogen bond interactions (C–HO and C–Hπ). This is an example of how simple molecules can form a highly complicated solid state structure.     

E-2-benzylidenebenzocyclanones. II. IR and mass spectrometric investigations

A series of E-2-benzylideneindanones (a) -tetralones (b) and -benzosuberones (c) with OCH₃ (2–4), NO₂ (5–7) and F (8–10) substituents in ortho, meta or para position was studied by IR and mass spectrometry. The most important IR bands were assigned and stated correlations between some frequencies and the stereostructure or conjugation feature of the molecules investigated. IR spectra were also analyzed in order to find frequencies characteristic of the size of the alkanone ring. The mass spectrometric investigation aimed at determining fragmentation pathways and finding correlations between them and the ring size of the alkanone ring or the position of the substituents.     

Practical synthesis of L-erythro- and L-threo-4-fluoroglutamic acids using aminoacylase

Enantiomerically pure L-erythro- and L-threo-4-fluoroglutamic acids 1a and 1b were conveniently prepared. The key steps in this synthesis relied upon separation of diastereomers of N-chloroacetyl-4-fluoroglutamic acid 5-methyl ester 7 by recrystallization and enzymatic resolution of enantiomers of the resulting 7(a+c) and 7(b+d) by aminoacylase. Protection of the γ-carboxyl group as a methyl ester was found to be crucial for this enzymatic reaction.     

Synthesis of mer-[RuCl3(DMSO)(bpy)], reactivity and electrochemistry of mer-[RuCl3(DMSO)(bpy)] and mer-[RuCl3(TMSO)(bpy)] complexes

[H(DMSO)₂][trans-RuCl₄(DMSO)₂] (1) reacts with 2,2′-bipyridine in ethanol at room temperature resulting in the formation of a major compound, mer-[RuCl₃(DMSO)(bpy)] (bpy = 2,2′-bipyridine) 3 and a known minor compound, cis-[RuCl₂(DMSO)₄] (4). The compounds 3 and 4 are formed via an anticipated intermediate mer-[RuCl₃(DMSO)₃] (2). The reaction of 3 and mer-[RuCl₃(TMSO)(bpy)] (5) with small molecules like imidazole, carbon monoxide and KSCN yield, mer-[RuCl₃(bpy)(im)] · 2DMSO (im = imidazole) (6) and cis-[RuCl₂(TMSO)(CO)(bpy)] (7), cis-[RuCl₂(DMSO)(CO)(bpy)] (8) and K[RuCl₃(bpy)(SCN)] (9), respectively. The formations of 3, 6 and 7 have been authenticated by single crystal structure determinations. Compound 6 is formed by the substitution of DMSO or TMSO from 3 and 5, respectively, whereas 7 and 8 are formed by unprecedented one-electron reductions of 5 and 3. The reactions of 3 and 5 with KSCN resulted in the same compound, K[RuCl₃(NCS)(bpy)] (9). DFT calculations were performed to distinguish whether the thiocyanate ligand is bound to ruthenium through S or N. In the ruthenium bipyridine systems, the HOMO contains ruthenium d-orbitals and the LUMO is typically π^*-orbitals of the bipyridine ring. Complexes 3, 6 and 7 are redox active in acetone and DMSO solvent showing prominent a reduction peak and corresponding oxidation peak.     

Vibrational spectra and structure of chlorine substituted cyclopropanes : Part I. cis-1,2,3-Trichlorocyclopropane

The synthesis of cis-1,2,3-trichlorocyclopropane is reported. The infrared spectra have been recorded between 4000 and 400 cm⁻¹ in the polycrystalline solid phase, and between 4000 and 200 cm⁻¹ in the gas phase. The spectrum of a solution in carbon disulphide was measured from 1400 to 400 cm⁻¹. The Raman spectrum has been obtained between 4000 and 100 cm⁻¹ in the solid phase. An assignment of the fundamentals of the title compound is proposed and compared with similar molecules. The spectrum unequivocally proves the C_JV structure of the molecule.     

Studies in stereochemistry—I Stereospecific routes to trans- anti- and cis- syn-Δ-dodecahydrophenanthrenes

Reduction of trans-1-oxo-7-methoxy-1,2,3,4,9,10,11,12-octahydrophenanthrene (XI) by lithium tri-t-butoxyaluminohydride gave trans-1β-hydroxy-7-methoxy-1,2,3,4,9,10,11,12-octahydrophenanthrene (XII) which on lithium—liquid ammonia reduction gave trans-anti-1β-hydroxy-7-oxo-Δ⁸⁽¹⁴⁾-dodecahydrophenanthrene (XIII). Reduction of cis-1-oxo-7-methoxy-1,2,3,4,9,10,11,12-octahydrophenanthrene (XV) by sodium borohydride gave cis-1-hydroxy-7-methoxy-1,2,3,4,9,10,11,12-octahydrophenanthrene (XVI) which on lithium—liquid ammonia reduction gave cis-syn-1-hydroxy-7-oxo-Δ⁸⁽¹⁴⁾-dodecahydrophenanthrene (XVII).     

Trapping of unstable molecular conformations in argon matrices: Gauche- and trans-1,2-difluoroethane

Experiments are reported which describe the trapping of the unstable trans conformer of 1,2-difluoroethane in argon matrices. Assignments of the infrared spectra of the gauche and trans conformers are given. The latter is shown to have a 600 cal/mol higher free enthalpy.     

cis- and trans-N-(Benzylsulfinyl)hexahydrobenzoxazolidin-2-ones as novel chiral sulfinyl transfer reagents

The synthesis of N-benzylsulfinyl derivatives 5a–d from both pairs of enantiomeric hexahydrobenzoxazolidin-2-ones 4a–d is reported. The use of 5a–d as effective chiral sulfinylating reagents in the preparation of enantiopure sulfoxides (e.e.>98%) is also reported.     

Tautomeric properties, conformations and structure of N-(2-hydroxy-5-chlorophenyl) salicylaldimine

The crystal structure of N-(2-hydroxy-5-chlorophenyl) salicylaldimine (C₁₃H₁₀NO₂Cl) was determined by X-ray analysis. It crystallizes orthorhombic space group P2₁2₁2₁ with a=12.967(2) Å, b=14.438(3) Å, c=6.231(3) Å, V=1166.5(6) Å³, Z=4, D_c=1.41 g cm⁻³ and μ(MoK)=0.315 mm⁻¹. The title compound is thermochromic and the molecule is nearly planar. Both tautomeric forms (keto and enol forms in 68(3) and 32(3)%, respectively) are present in the solid state. The molecules contain strong intramolecular hydrogen bonds, N1–H1O1/O2 (2.515(1) and 2.581(2) Å) for the keto form and O1–H01N1 for the enol one. There is also strong intermolecular O2–HO1 hydrogen bonding (2.599(2) Å) between neighbouring molecules. Minimum energy conformations AM1 were calculated as a function of the three torsion angles, θ₁(N1–C7–C6–C5), θ₂(C8–N1–C7–C6) and θ₃(C9–C8–N1–C7), varied every 10°. Although the molecule is nearly planar, the AM1 optimized geometry of the title compound is not planar. The non-planar conformation of the title compound corresponding to the optimized X-ray structure is the most stable conformation in all calculations.     

Proton magnetic resonance studies of cyclic compounds—III cis- and trans-2,6-dimethylmorpholines

Commercial 2,6-dimethylmorpholine has been separated into cis- and trans-isomers by vapour phase chromatography. The PMR spectra of the bases, analysed as ABXK₃ systems (J_AK = J_BK = 0), show that the most abundant isomer has the cis-configuration, consisting probably of a single conformation in which both methyl groups are equatorial. The trans-isomer is probably a mixture of rapidly inverting and energetically equivalent conformations, since the vicinal coupling constants deduced from the PMR spectrum are averages of those expected for the two conformations.     

Mono- meso- tert-butylporphyrin

Treatment of meso-tetra(tert-butyl)porphyrin with sulfuric acid/n-butanol affords a mixture of porphyrin and mono-tert-butylporphyrin in relatively high yield.     

Fluorocyclohexanes-II Cis- and trans- 1H:3H- and 1H:4H-decafluorocyclohexanes

An extension of the methods employed in the isolation of (trans) 1H/2H-decafluorocyclohexane,¹ (I) from the polyfluorocyclohexane mixture obtained by the vapour phase fluorination of benzene with cobaltic fluoride at about 150°, has afforded the four remaining members of the series of decafluorocyclohexanes [the cis- and trans-1H:3H- and 1H:4H-isomers (1H:3H/-(IV), 1H/3H-(III), 1H:4H/-(VII), and 1H/4H-(VIII), respectively)] and also the cis-1H:2H-decafluorocyclohexane (II), obtained previously^1,2 by the lithium aluminium hydride reduction of 1:2-dichlorodecafluorocyclohexane. The structures of the 1H:3H- and 1H:4H-decafluorides have been established by dehydrofluorination studies. The six decafluorocyclohexanes have been related to two new nonafluorocyclohexanes³ (IX and X) by further fluorination of the latter. 2H-Heptafluoroadipic acid has been obtained from 3H-nonafluorocyclohex-1-ene (V), one of the dehydrofluorination products of the 1H:3H-decafluorides.     

The remote effect of vicinal large groups on the anomeric equilibrium: 2-methoxy-cis- and -trans-5,6-dimethyltetrahydropyrans

The anomeric equilibrium of 2-methoxy-trans-5,6-dimethyltetrahydropyran was found to have an enhanced fraction of axial methoxyl compared to 2-methoxy-4- or 6-methyltetrahydropyran. The 2-methoxy-cis-5,6-dimethyltetrahydropyran did not. The enhanced anomeric effect is attributed to a steric repulsion between the trans vicinal Me groups. A similar effect is postulated for methyl glucoside and glucose pentaacetate.     

顺、反-1,2-环己二胺对有机-无机杂化锑碘异构体的影响

在浓氢碘酸水溶液中,顺式和反式-1,2-环己二胺(DAC)分别与三碘化锑反应得到2种有机-无机杂化异构体(cis-1,2-DACH_2)[SbI_5]·H_2O(1)和{(trans-1,2-DACH_2)[SbI_5]·H_2O}_n(2)。X射线单晶衍射表明化合物1中的无机成分是由2个[SbI_6]八面体通过共I-I边形成的二聚体[Sb_2I_(10)],而化合物2中的无机部分是[SbI_6]八面体通过共享顶点形成的一维锯齿链。此外,利用紫外-可见光谱、荧光光谱和密度泛函理论对化合物1和2进行了比较研究。     

Crystal and Molecular Structure of (trans-3,4-Diamino-2,2,6,6-tetramethylpiperidine-1-oxyl-N3, N4)(oxalato-O,O′)platinum(II) Dihydrate

The crystal and molecular structure of (trans-3,4-diamino-2,2,6,6-tetramethylpiperidine-1-oxyl-N ³, N ⁴)(oxalato-O,O′)platinum(II) dihydrate was studied by single crystal X-ray diffraction. The crystals belong to the monoclinic system; a 8.261, b 13.129, c 15.224 Å; β 104.29°, Z 4, space group P2₁/n. The structure was solved by the direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R 0.026 for all the 3660 measured unique reflections. The structure consists of individual mononuclear bischelate molecules containing two different bidentate ligands. The Pt²⁺ coordination is distorted square-planar. The complex molecules and water molecules in the crystal of I are linked by hydrogen bonds forming an infinite 3D network. __________ Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 11, 2005, pp. 1893–1897. Original Russian Text Copyright ? 2005 by Chekhlov.     

Crystal structure and IR spectrum of 1-O-α- -glucopyranosyl- -mannitol–ethanol (2/1)

1-O-α- -Glucopyranosyl- -mannitol–ethanol (2/1), (C₁₂H₂₄O₁₁)₂–C₂H₅OH, crystallizes in the monoclinic space group P2₁ with unit cell dimensions a=11.4230(8) Å, b=9.525(4) Å, c=15.854(2) Å, β=102.751(7)° and V=1682.4(7) ų, Z=2, D_x=1.45 Mg m⁻³, λ (Mo-K_α)=0.71069 Å, μ=0.128 mm⁻¹, F(000)=788 and T=293(2) K. The structure was solved by direct methods and refined by least-squares calculations on F² to R₁=0.0371[I>2σ(I)], and 0.0930 (all data, 3542 independent reflections, R_int=0.021). There are two molecules of glucopyranosylmannitol (GPM) and one ethanol molecule in the asymmetric unit, and the glucopyranosyl ring adopts a chair conformation in both GPM molecules. Bond lengths and angles accord well with the mean values of related structures. The conformation along the mannitol side chain for one of the GPM molecules was the same as for the known polymorphs of -mannitol, while the conformation of the other molecule was different, indicating different conformational arrangements in the terminal carbon atoms of the mannitol side chains of the two GPM molecules. The structure in 1-O-α- -glucopyranosyl- -mannitol–ethanol (2/1) is held together by a very complex hydrogen bonding system, which consists of an infinte chain propagating along the b-axis and a discontinuous chain, which binds the ethanol molecule to the structure. The FTIR spectra for anhydrous GPM, GPM dihydrate and GPM–ethanol (2/1) were recorded. Both IR and X-ray results indicate the extensive hydrogen bonding in crystalline state.     

Synthesis, crystal and molecular structures, and steroechemical nonrigidity ofN-(chlorodimethylgermylmethyl)-andN-(bromodimethylgermylmethyl)-N-[(S)-1-phenylethyl]acetamides andN-(chlorodimethylgermylmethyl)-4-phenyl-2-pyrrolidone

RacemicN-(chlorodimethylgermylmethyl)-4-phenyl-2-pyrrolidone and the first optically active amide derivatives containing the asymmetrical carbon atom and the five-coordinate germanium atom,viz.,N-(chlorodimethylgermylmethyl)- andN-(bromodimethylgermyl-methyl)-N-[(S)-1-phenylethyl] acetamides, were synthesized. Their structures were established by X-ray diffraction analysis. The geometric characteristics of the trigonal-bipyramidal valence environment about the germanium atoms are compared with those of analogous enantiomeric silicon compounds and the related five-coordinate germanium compounds. The barriers to permutational isomerization of the title compounds were determined by dynamic¹H NMR spectroscopy. It was found that these barriers are higher than those of the corresponding silicon analogs. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 137–144, January, 2000.     

Structural, spectral and thermal studies of N-2-(4-picolyl)- and N-2-(6-picolyl)-N′-(2-chlorophenyl)thioureas and N-2-(6-picolyl)-N′-(2-bromophenyl)thiourea

N-2-(4-picolyl)-N′-2-chlorophenylthiourea, 4PicTu2Cl, monoclinic, P2₁/c, a=10.068(5), b=11.715(2), β=96.88(4)°, and Z=4; N-2-(6-picolyl)-N′-2-chlorophenylthiourea, 6PicTu2Cl, triclinic, P-1, a=7.4250(8), b=7.5690(16), c=12.664(3) Å, =105.706(17), β=103.181(13), γ=90.063(13)°, V=665.6(2) ų and Z=2 and N-2-(6-picolyl)-N′-2-bromophenylthiourea, 6PicTu2Br, triclinic, P-1, a=7.512(4), b=7.535(6), c=12.575(4) Å, a=103.14(3), β=105.67(3), γ=90.28(4)°, V=665.7(2) ų and Z=2. The intramolecular hydrogen bonding between N′H and the pyridine nitrogen and intermolecular hydrogen bonding involving the thione sulfur and the NH hydrogen, as well as the planarity of the molecules, are affected by the position of the methyl substituent on the pyridine ring. The enthalpies of fusion and melting points of these thioureas are also affected. ¹H NMR studies in CDCl₃ show the NH′ hydrogen resonance considerably downfield from other resonances in their spectra.