Determination of structure and 13C chemical shift assignments of the nitration products of 2-chloro-10-methylphenothiazine. X-Ray molecular structure of 2-chloro-7-nitro-10-methylphenothiazine 5-oxide

Nitration of 2-chloro-10-methylphenothiazine, 1 , yields two mono-nitro compounds identified as sulfoxide 2 and sulfone 3 . The nmr analyses of the ¹³C spectra of 2 and 3 establish unequivocally that in both compounds substitution has occurred at the seven position. This is supported by the X-ray crystal structure of one of the compounds 2-chloro-7-nitro-10-methylphenothiazine 5-oxide, 2 , which also shows that the sulfoxide group is in the “pseudo-axial” configuration. Crystals of 2 are monoclinic, space group P2₁/n, a = 11.606(4), b = 13.970(4)Å, c = 9.837(2), β = 127.49(2)° and Z = 4. The structure has been refined by full-matrix least-squares to R = 0.033 and R_w = 0.035, using 1704 observed reflections.     

Structure and bonding in 9-hydroxy-1,4-dimethylthioxanthenium bis(carbomethoxy)methylide and related ylides

The single-crystal X-ray structures of 9-hydroxy-1,4-dimethylthioxanthenium bis(carbomethoxy)methylide and 1,4-oxathianium bis(carbomethoxy)methylide are reported. The methylide carbon of the former is pseudo-axial while that of the latter is equatorial. The former exhibits a strong intramolecular hydrogen bond to a carbonyl oxygen atom.     

Synthesis and characterization of ruthenium(ii) complexes of 5-hydroxyflavones

Bis(dimethyl sulfoxide)bis(flavonato)ruthenium(II) complexes, RuL₂(DMSO)₂, were synthesized by the reaction of dichlorotetrakis(dimethyl sulfoxide)ruthenium(II) with the sodium salts of 5-hydroxyflavone, 5-hydroxy-4′-methoxyflavone and 5-hydroxy-3′,4′,5′,7-tetramethoxyflavone, ( L ). The complexation was followed by ¹H nmr spectroscopy. The 1:1 kinetically favoured tris(dimethyl sulfoxide)chloroflavonatoruthenium(II) complexes, RuLCl(DMSO)₃, were initially formed and then transformed into the thermodynamically more stable ones. Each one of these complexes, by reacting with another equivalent of lig-and L, also gave rise to a mixture of 1:2 kinetic species, from which the 1:2 thermodynamically more stable bis(dimethyl sulfoxide)bis(flavonato)ruthenium(II) complexes, RuL₂(DMSO)₂, were formed. The complexes were characterized by extensive studies involving ¹H, ¹³C nuclear magnetic resonance, infrared and ultraviolet-visible spectroscopy, mass spectrometry, cyclic voltammetry and elemental analysis. Such 1:2 complexes exhibited properties of two nonequivalent flavonate ligands and also of two non-equivalent dimethyl sulfoxide ligands; one of these dimethyl sulfoxide ligands is considered to be S-bonded and the other O-bonded. Also two quasireversible one-electron redox steps were observed at 0.53 to 0.57 and 0.44 to 0.41 V (vs Saturated Calomel Electrode). The spectroscopic results obtained allow for the discussion of stereochemistry of each bis(dimethyl sulfoxide)bis(flavonato)ruthenium(II) complex and to postulate its possible structure as one corresponding to the more anisochronous species.     

The structure of thianthrenium biscarbethoxymethylide and the corresponding sulfoxide

Thianthrene reacts with one equivalent of diethyl diazomalonate to form the monosulfonium ylide thianthrenium biscarbethoxymethylide. Single crystal X-ray and ¹³C-nmr establish the conformation as pseudoequatorial (e') in both the solid state and solution. The angle of fold between aryl rings is 135.7°, the nearlyplanar malonylide fragment bisecting this angle. The carbonyl oxygen of the endo carbethoxy group is anti to the nonbonding electron pair on sulfur. The methylide carbon resonates at 50 ppm. The aromatic solvent induced shift (ASIS) technique indicates that thianthrene S? oxide also is e'.     

Complete assignment of the 1H and 13C NMR spectra of 4-methoxy-3′-methylsulfinyl-3,4′-diquinolinyl sulfides

The ¹H and ¹³C nmr spectra of 4-methoxy-3′-methylsulfinyl-3,4′-diquinolinyl sulfides 2, 3 and 4 were totally assigned using a combination of nmr techniques. As compared to the spectral data of sulfoxide 2 typical values of nitro group substituents effects in nitroquinolines 3 and 4 were observed. The H-2′ protons in sulfoxides 2, 3 and 4 are strongly influenced by ortho methylsulfinyl group and deshielded by about 0.7 ppm. PM3 method calculations support the structural conclusion that sulfinyl group oxygen points in direction of the positions 2′.     

Beyond the corey reaction: one-step diolefination of cyclic ketones

The reactivities of the cyclic ketones cycloheptanone, cyclodecanone, and cycloundecanone with dimethylsulfoxonium methylide generated from trimethylsulfoxonium iodide and base (NaH) were studied in diglyme at 130 degrees C. Oxiranes, which primarily form via the Corey reaction, lead to ring expansions to give oxetanes and oxacyclopentanes when an excess of dimethylsulfoxonium methylide is used. The Corey reaction is suppressed in the presence of excess of base, and 1,3-terminal dienes form instead (we term this reaction the Yurchenko diolefination). Our mechanistic proposal involves the deprotonation of the betaine that forms after the attack of dimethylsulfoxonium methylide on the carbonyl group of the ketone. The key step of the diolefination reaction involves a [2,3]-sigmatropic rearrangement of the ylide to a gamma-unsaturated sulfoxide with a barrier of 9.9 kcal/mol (DeltaH298, MP2/cc-pVDZ, for the cycloheptane derivative). The elimination of sulfenic acid from the gamma-unsaturated sulfoxide in the terminal step of the diolefination is associated with a higher barrier (17.3 kcal/mol) but is strongly accelerated in the presence of base. The reactivity of cyclic ketones in the Yurchenko reaction depends on the ring size; medium-sized cyclodecanone is less reactive than either cycloheptanone or cyclododecanone.     

Synthesis and characterization of 7, 16‐bis(phenylazo)tetraaza[14]annulenes

The diazo coupling reaction between a tetraaza[14]annulene ( 1 ) and a series of 4‐substituted phenyl‐diazonium tetrafluoroborates yielded the corresponding 7, 16‐disubstituted products. Mass spectra indicate the presence of molecular ion peaks that substantiate the 7,16‐disubstituted products ( 4 ); the lack of olefinic proton signals corresponding to the 7,16‐ position in the ¹H nmr spectra of 4 also show that diazo coupling has taken place. Analysis of signals corresponding to the methyl groups of 4 in their ¹H and ¹³C nmr spectra indicate that the imine‐bis‐hydrazone form is present for compounds that do not contain p‐methoxyphenyl groups. However, analysis of methyl signals in the nmr specta of compounds 4 containing p‐methoxyphenyl groups show that the bis‐azo form and the imine‐bis‐hydrazone form are present through tautomerism. Complexation with nickel(II) ion induces the formation of the bis‐ azo structure.     

硫杂蒽酮的合成和表征

为了寻求合成硫杂蒽酮的高效新方法,以2,2′-二硫代二苯甲酸和苯酚为原料,硫酸为溶剂和催化剂,考察了沸石分子筛、Al2O3和P2O5、温度、原料的物质的量之比、反应时间对反应收率的影响,确定了最佳反应条件,推测了可能的反应过程;进而以2,2′-二硫代二苯甲酸和相应的苯衍生物为原料,在H2SO4-P2O5体系中于最佳反应条件下制备了13个硫杂蒽酮类化合物,并利用柱色谱分离以及红外光谱与核磁共振谱对产物进行表征.结果表明,在反应体系中引入P2O5有利于促进反应的完成;最佳反应条件为:温度70℃、2,2′-二硫代二苯甲酸/苯衍生物物质的量之比1∶6、反应时间6h.邻苯二酚与二硫代水杨酸的反应产物——化合物11(a)和11(b)为同分异构体.     

N1-substituted 3,5-dimethoxy-4-halogeno-1H-pyrazoles: Synthesis and NMR study

The synthesis of 1-methyl- and 1-benzyl-3,5-dimethoxy-4-halogeno-1H-pyrazoles is described. Moreover, detailed nmr spectroscopic studies with the title compounds are presented. The highly shielded pyrazole C-4 atom in the corresponding 4-iodo congeners was found to have a ¹³C-chemical shift of only ?27 ppm.     

Thermolysis of Imidates: A New Method for the Generation of Carbonyl Ylides

Thermolysis of dimethyl 2‐[(3‐oxo‐3H‐isoindol‐1‐yl)oxy]malonate ( 8 ) promotes a [1,4]‐H shift in the imidic ? N?C? O? CH? fragment of the starting molecule, which leads to a reactive carbonyl ylide. This carbonyl ylide can be trapped by the C?N bond of imidates and imines, as well as the C?O bond of benzaldehyde. The corresponding cycloadducts 11, 14 , and 16 are formed regioselectively in good yields (60–95%) and with high stereoselectivity. In the case of 11 , the minor cycloadduct in solution undergoes an isomerization to give the more stable stereoisomer. The structures of two cycloadducts, i.e., 11a and 14a , have been established by X‐ray crystallography.     

Specific Interactions and the Nature of the Chemical Nonequivalence of Chlorine Atoms in the ECl<Subscript>3</Subscript> Group (E = C,P) of Trichlorophosphonium Ylides and Isomeric Dichloro(trichloromethyl)phosphine

The nature of the asymmetry of the ECl₃ group (E = C, P) in dichloro(trichloromethyl)phosphine and trichlorophosphonium methylide and dichloromethylide was studied by nonempirical and MNDO-PM3 calculations and ³⁵Cl NQR spectroscopy. The chemical nonequivalence of chlorine atoms in the CCl₃ group of dichloro(trichloromethyl)phosphine is caused by steric interaction with the PCl₂ fragment. In the PCl₃ group of trichlorophosphonium methylide and dichloromethylide, this nonequivalence arises from specific interactions with the lone electron pair of the ylide carbon atom, whose p-character is about 94% on the RHF/6–311⁺⁺G(3df,3pd) level. The alteration of the type of interaction predicts inversion of the ³⁵Cl NQR signals of the PCl₃ group in trichlorophosphonium ylide and dichloromethylide in relation to those of the CCl₃ group in the experimental spectrum of dichloro(trichloromethyl)phosphine. The MNDO-PM3 method characterizes dichloro- and diphenylmethylides as unstabilized structurally stable ylides.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 7, 2005, pp. 1148–1153.Original Russian Text Copyright © 2005 by Romanenko.     

Two-dimensional NMR studies of 2-substituted thioxanthene sulfoxides

2-Fluoro-, 2-chloro-, 2-bromo-, 2-methyl-, and 2-methoxythioxanthene have been prepared by borane reduction of the corresponding thioxanthone. The corresponding sulfoxides were prepared by m-chloroperoxybenzoic acid oxidation of these sulfides. Proton and carbon chemical shifts have been assigned to these thioxanthene sulfoxides with the aid of LROCSCM and SROCSCM experiments. Carbon chemical shifts in the unsubstituted rings occur at approximately 125 ppm (C5); 128 ppm (C6); 130 ppm (C7); 128 ppm (C8); and 36 ppm (C9). The methylene protons appears as AB doublets at approximately 4.2 and 3.8 ppm. All sulfoxides have the same, pseudo-equatorial geometry.     

Direct Difluoromethylation of Alcohols with an Electrophilic Difluoromethylated Sulfonium Ylide

A general method for the formation of alkyl difluoromethylethers under mild reaction conditions and with good functional‐group tolerance was developed. The development of the method was based on the invention of a stable, electrophilic, difluoromethylating reagent, difluoromethyl‐(4‐nitrophenyl)‐bis(carbomethoxy) methylide sulfonium ylide, which was synthesized by reaction of the easily available 4‐nitrophenyl (difluoromethyl)thioether and dimethyl diazomalonate in the presence of a rhodium catalyst.     

Azabicyclo chemistry. 7. Ultra-high field (600 MHz) NMR spectroscopy in solving conformational problems: cis-Octahydroindoles

Studies using ultra-high field (600 MHz) nmr spectroscopy has allowed us to assign the conformational preference of cis-octahydroindoles, including the position of their nitrogen lone-pair electrons. Lithium aluminum hydride reduction of cis-octahydroindol-2-one ( 4 ) gave cis-octahydroindole ( 5a ) which showed three distinct nmr resonances, the C7a proton at δ 3.04 (apparent q, J = 5.3 Hz) and the two C2 protons at δ 3.10 and 2.94. The latter two resonances were absent in the C2 deuterated compound 5b . Deuteromethylation of 5a , via a urethane intermediate, gave 1-deuteromethyl-cis-octahydroindole ( 8a ) which showed resonances at δ 3.12 for the α-faced C2 proton, the β-faced C2 proton at δ 2.17, and the C7a proton at δ 2.15. The resonances at δ 3.12 and 2.17 are absent in the corresponding C2 deuterated compound 8b , and the C7a remains as a doublet of triplets (d, J = 5.5 Hz; t, J = 3.8 Hz). Interpretation of the above data led us to assign 8a as the cis compound with nitrogen axial, and the lone pair electrons in a pseudo-axial position and antiperiplanar to the C7a and β-faced C2 protons. The amine 5a is also cis and has the nitrogen axial, but the lone pair electrons are pseudo-equatorial. Inspection of the Bohlmann band region in the ir of 5a and 8a supports the above assignments. These investigations thus suggest, in cis-octahydroindoles, the following steric order: methyl > lone pair > H.     

Mass spectral characteristics of the sulfur-containing ketoxime carbamates thiofanox and metabolites

Deuterium labeling and high resolution mass spectroscopy have been used to determine the modes of electron impact fragmentation of 3,3-dimethyl-1-methylthio-2-butanone O-[(methylamino)carbonyl]oxime, thiofanox and its metabolites, the sulfoxide and sulfone. The mass spectra of the corresponding oximes were also examined. The carbamates fragmented chiefly by two competing pathways—the loss of CH₃N?C? O or the sulfur-containing moiety. The favored process was dependent on the oxidation state at sulfur. Several unusual rearrangements were noted.     

Molecular rearrangements of 4-iminomethyl-1,2,3-triazoles. Replacement of 1-aryl substituents in 1H-1,2,3-triazole-4-carbaldehydes

The two structural isomers, 4 and 5 , of 1-substituted-4-iminomethyl-1,2,3-triazoles are interconvertible when heated in dimethyl sulfoxide at 80°. The equilibrium position depends on the electronic properties of the R-substituent, favoring 5 for R = alkyl, benzyl and anisyl, and 4 for p-chlorophenyl and p-nitrophenyl. An interesting application is the synthesis of 1-alkyl-1,2,3-triazole-4-carbaldehydes from 1-phenyl-1,2,3-triazole-4-carbaldehyde by Scheme I. The hydrazones 4ij and the oxime 4k do not rearrange due to an unfavorable Z-configuration around the C ? N bond, whereas the acyloximino derivative 4m is converted into the nitrile 11 . The structures of the products have been fully characterized by ¹³C nmr spectroscopy and the mechanistic details of the rearrangement are discussed.     

磷叶立德CH2PH3和类磷叶立德自由基∙CHPH3优势构型和C—P键结构的研究

采用MP4/6-311++G(d,p)和B3LYP/6-311++G(d,p)对磷叶立德CH₂PH₃和类磷叶立德自由基∙CHPH₃进行构型优化，从电子密度拓扑分析的角度对C—P键的键结构进行了探讨。得到如下结论：类磷叶立德自由基和磷叶立德的C—P键性质类似，但磷叶立德中π键由两个电子形成，类磷叶立德自由基中π键由一个电子形成，所以前者的π性明显，而后者的π性不明显。类磷叶立德自由基中的这个单电子在碳原子附近，垂直于对称面的方向上运动，有p_(C→P)配键的特征，所以类磷叶立德自由基∙CHPH₃中的C—P键比相应的产物∙CH₂PH₂中的C—P键要弱一些。     

Preparation of polyimides utilizing the Diels–Alder reaction,II: Bis[N-(butadienyl-2-methyl)] amino arylenes with bismaleimides

Four new bisdienes were prepared from 2-bromomethyl-1,3-butadiene and N,N-diethyl benzidine; bis[4-(N-ethyl) aminophenyl]-p-diisopropylbenzene, 1,4-diamino-2,3,5,6-tetramethylbenzene and α,α′ bis(4-amino-3,5-dimethyl phenyl)-p-diisopropyl benzene. Polyimides were synthesized by the Diels–Alder reaction of these bisdienes and bis(4-maleimidylphenyl)methane and bis(3-maleimidylphenyl) sulfone. The polymers were soluble in m -cresol, dimethyl sulfoxide and chlorinated hydrocarbon solvents. Moderate thermal stability was observed by thermogravimetric analysis in air and nitrogen.     

Determination and Persistence of Bay 68138 and Two of its Metabolities in Turf Grass

Residues of Bay 68138 (Nemacur P^®) [ethyl 4-(methylthio)-m-tolyl isopropylphosphor-amidate] and its sulfoxide and sulfone were determined in turf grass. The extracts were separated by liquid chromatography on silica gel into two fractions which were concentrated and injected into a gas chromatograph equipped with a flame photometric detector sensitive to phosphorus. Recoveries were 95 to 105 % for all three compounds at the 0.10-ppm level; sensitivity to each compound was 0.01 ppm or better. Retention times for the three compounds on six liquid phases, p-values in seven solvent systems, and conditions for separating the compounds by liquid chromatography were determined. Total residues in turf grass treated with a granular formulation at the rate of 15 lb (active ingredient) per acre, declined from 4930 to 102 ppm (dry basis) during a 49-day period of weathering. Bay 68138 was found to oxidize to its sulfoxide and sulfone.     

Stereochemistry of cycloadducts from 3,4-dihydro-6,7-dimethoxyisoquinoline ylide and olefins

Cycloaddition of 2-methoxycarbonylmethyl-3,4-dihydro-6,7-dimethoxyisoquinolinium ylide with various E-substituted olefin type dipolarophiles gave products of 10b-H, 1-H, 2-H and 3-H α,α,β,β-relative configuration with one exception. Relative configuration of compounds prepared has been determined by 1D and 2D ¹H and ¹³C nmr techniques. It has also been detected that a triple trans ? cis-1 ? cis-2 conformation equilibrium exists in solution.