The first separation and stereochemical determination of bis(α-hydroxyalkyl) phosphinic acids diastereoisomers

A separation of bis(α-hydroxyalkyl) phosphinic acid diastereoisomers is described. A novel method for the determination stereochemistry of bis(α-hydroxyalkyl) phosphinic acid diastereoisomers has been developed. The stereochemistry of one diastereoisomer was confirmed after converting to the corresponding methyl ester using trimethyl orthoformate.     

C2-symmetrical bis(camphorsulfonamides) as chiral ligands for enantioselective addition of diethylzinc to benzaldehyde

Purpose of the research was to determine the activity of chiral bis(sulfonamide) ligands derived from camphor in the addition of diethylzinc to benzaldehyde. Chiral bis(ketosulfonamides) and bis(hydroxysulfonamides), have been synthesized in a reaction of diamines with camphorsulfonic acid chloride. Their activity in a reaction of asymmetric addition of dialkylzinc to benzaldehyde in a presence of titanium(IV) tetraisopropoxide was determined. The bis(ketosulfonamide) ligands reveal low enantioselectivity, with the ee% not exceeding 12%. The bis(hydroxysulfonamides) reveal much higher asymmetric induction in the investigated ZnEt₂ addition. The best enantiomeric excess (62%) has been observed for bis(hydroxysulfonamide) obtained from 1,3-diaminepropane. The yields of the reaction obtained after 18 h are 92–96%. Crystal structures have been solved for bis(ketosulfonamide) ligands obtained from diamines based on C₂ to C₄ chain. The (2R) configuration in the rings systems of bis(hydroxysulfonamide) containing the C₃ bridge was also determined by the crystal structure analysis. The sulfonamides have been characterized by IR, ¹H and ¹³C NMR.     

A facile one‐pot synthesis of tetrahydropyrimidines part 3 Synthesis of [alkanediylbis(3‐alkyl/aralkyl/aryl‐3,6‐dihydropyrimidine‐1,5(2H)‐diyl)bis(arylmethanones) and [1,4‐phenylenebis(3‐phenyl‐3,6‐dihydropyrimidine‐1,5(2H)‐diyl)]bis(phenylmethanone)

A facile one‐pot synthetic strategy has been developed for novel [alkanediylbis(3‐alkyl/aralkyl/ aryl‐3,6‐dihydropyrimidine‐1,5(2H)‐diyl)]bis(arylmethanones) 2a‐c, 2e‐m and [1,4‐phenylenebis(3‐phenyl‐3,6‐dihydropyrimidine‐1,5(2H)‐diyl)]bis(phenylmethanone) 2d by refluxing enaminones 1a‐f in methanol with diamines and formaldehyde.     

Molecular structure and bonding properties of bis(1-methylimidazole)bis(perchlorato)bis(pyridineN-oxide)copper(II)

Summary The crystal and molecular structure of bis(1-methylimidazole)bis(perchlorato)bis(pyridineN-oxide)copper(II) have been determined using three-dimensional x-ray diffraction data. The complex crystallizes in space group P2₁/c with Z=2. The cell dimensions area=9.355(3),b=14.363(4),c=9.698(4) Å, and =106.40(3)^o. Least-squares refinement of the structure has yielded a final R value of 0.049 for 1235 independent reflections. The centrosymmetric structure consists oftrans pairs of 1-methylimidazole and pyridineN-oxide figands forming a square planar geometry with Cu–N and Cu–O bond lengths of 1.963(4) Å and 1.948(4) Å, respectively. The two perchlorate ions are located above and below the square plane with Cu–O distances of 2.590(5) Å. The uv-vis and i.r. spectra and bonding properties of the title compound are discussed with reference to the structure.     

Synthesis and characterization of bis(2-aminophenyl)disulphide diimine derivatives and their ruthenium complexes

Condensation of bis(2-aminophenyl)disulphide with aromatic aldehydes yielded the corresponding dithiophenyldiimines. Dinuclear ruthenium complexes were obtained by reacting the diimines (3) [bis(3-nitrobenzaldehyde)-phenyldisulphide diimine], (5) [bis(2-chlorobenzaldehyde)-phenyldisulphide diimine], (8) [bis(2-methoxybenzaldehyde)-phenyldisulphide diimine] and (9) [bis(2-hydroxybenzaldehyde)-phenyldisulphide diimine], with RuCl₃ in the presence of L (L=2,2-bipyridine, 1,10-phenanthroline, 3,4-diaminotoluene, pyridine and PPh₃) in EtOH. The two metal centres, connected through bridging chlorides, are in octahedral environments with one metal centre coordinated to sulphur and water while the other is coordinated to L.     

Isotope exchange between bis/diethyl dithiocarbamate/ copper/II/ complex and Cu2+ ion

Isotope exchange behaviour of bis/diethyl dithiocarbamate/ copper/II/ complex has been studied at 30 °C and 40 °C varying the concentration of the complex and metal ion. Results indicate that the complex is labile in chloroform dimethyl sulphoxide medium. Increase in concentration has significant effect on the rate of the reaction. Similarly the increase in temperature increased the rate of the reaction.     

Synthesis of the bis(2′-chloroethyl) amide of β-(8-guanyl)propionic acid

The synthesis of -(8-guanyl)propionic acid and its chloride, methyl ester, bis(2-hydroxyethyl)amide, and bis(2-chloroethyl)amide has been effected. The latter readily rearranges under certain conditions into 2-chloroethylaminoethyl -(8-guanyl)propionate.     

Synthesis and mechanism of the formation of bis(methylamides) of pyrazoledicarboxylic acids

The reaction of ethoxymethyleneoxaloacetic ester with phenylhydrazine and methylhydrazine has been studied. It has been established that the addition of phenylhydrazine takes place to the ethoxy group through the -nitrogen atom, and the addition of methylhydrazine to the ethoxy group predominantly through the -nitrogen atom. Several derivatives of -alkyl(aryl)hydrazinomethyleneoxaloacetic esters have been obtained. A series of bis(methylamides) and several diamides of 1-alkyl(aryl)pyrazoledicarboxylic acids have been synthesized. Their structure has been determined on the basis of their UV spectra and their breakdown by hydrolysis to known acids. It has been found that in the alkylation of an ester of 3,4-pyrazoledicarboxylic acid with alkyl halides followed by amidation, two isomeric bis(methylamide)s are formed, apparently with the predominance of derivatives of 1-alkyl-3, 4-pyrazoledicarboxylic acids. It has been established that the bis(methylamide)s of 1-alkyl-3,4-pyrazoledicarboxylic and of 1-alkyl-4, 5-pyrazoledicarboxylic acids have characteristic UV spectra differing from one another. The bis(methylamide)s obtained are pharmacologically active substances.     

Mechanism of the reaction of bis(α-hydroxyalkyl)phenyl-phosphine sulfides with dimethylformamide dimethylacetal

Conclusions The reaction of bis(-hydroxyalkyl)phenylphosphine sulfides with dimethylformamide dimethylacetal proceeds with the formation of the O-methyl alkylphenylthiophosphinates.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2551–2555, November, 1987.     

Isotope exchange behaviour of bis/diethyldithiocarbamate/mercury/II/ complex

Isotope exchange behaviour of bis/diethyldithiocarbamate/mercury/II/ complex has been studied at 25°C and 45°C varying the concentrations of both metal ion and the complex. The results show that the complex is kinetically labile. Temperature has a significant effect on the rate of the reaction. Increase in concentration increases the reaction rate.     

Synthesis of novel bis(chromenes) and bis(chromeno[3,4-C]pyridine) incorporating piperazine moiety

Novel bis(2-oxo-2H-chromene) as well as bis(2-imino-2H-chromene) derivatives incorporating piperazine moiety were prepared by the cyclocondensation reaction of bis(2-hydroxybenzaldehyde) with two equivalents of each of the appropriate β-ketoesters or acetonitrile derivatives. The bis(2-imino-2H-chromene-3-carbothioamide) derivative was used as a key synthon for construction of novel bis(3-(4-substituted thiazol-2-yl)-2H-chromen-2-one) derivatives via its cyclocondensation with a series of the appropriate α-halocarbonyl derivatives. Moreover, the bis(2-hydroxybenzaldehyde) reacted with four equivalents of the appropriate acetonitrile derivatives to afford the corresponding bis(3H-chromeno[3,4-c]pyridine) derivatives. Elucidation of the structure of the novel bis(chromenes) bearing piperazine nucleus was established by the spectral data and elemental analyses.     

Chemical reactions of cycloalkanespirohydantoins. Part 3. Acid-catalyzed reaction of 4-hydroxy-2-imidazolidinones. Preparation of bis(1,3-diaza-2-oxospiro[4,5]decyl-4) ether

The use of N-carbamoyliminium ion initiated reactions for the generation of spiroimidazolidin-2-ones has been successfully exploited. N₃-Substituted-4-hydroxy-2-imidazolidinones have been treated under acid conditions to give the rearranged imidazolinones. Only in the case of N₃-dialkylaminomethyl-4-hydroxy-5-cyclohexanespiro-2-imidazolidinones upon treatment with trifluoroacetic anhydride/trifluoroacetic acid afforded a mixture containing bis(1,3-diaza-2-oxospiro[4,5]decyl-4) ether with the rearranged imidazolidinone.     

X-Ray and 31P CP MAS NMR studies of bis(dialkoxythiophosphoryl) disulfides

The crystal and molecular structures of the title compounds were determined by X-ray diffraction technique from diffractometer intensity measurements. It has been found that two homologous disulfides, bis(dimethoxythiophosphoryl) disulfide 1 and bis(dineopentoxythiophosphoryl) disulfide 2 , form different molecular and crystal structures with space groups C2/c and P&1macr;, respectively. These results were confirmed by ³¹P CP MAS NMR studies, which showed that under favorable conditions the solid state NMR may lead to determination of the number of crystallographically unique phosphorus atoms. Moreover, the variation of the disulfide S–S bond length versus torsional P–S–S–P angles was observed.     

Synthesis and characterization of sodium bis(trimethylstannyl) amide and bis(trimethylsilyl) bis(trimethylstannyl) -phospha-tetrazene

Sodium bis(trimethylstannyl)amide NaN(SnMe₃)₂, isolated by the reaction of trimethylstannyldiethylamine with sodium amide, reacts with tris(trimethylsilyl)hydrazino—dichloro-phosphine to form bis(trimethylsilyl)bis(trimethylstannyl)-2-phospha-2-tetrazene, (Me₃Si)₂N-N=P-N(SnMe₃)₂. Both the molecules have been isolated and characterized.     

Gold(I)-catalyzed sequential cycloisomerization/bis-addition of o-ethynylanilines: an efficient access to bis(indolyl)methanes and di(indolyl)indolin-2-ones

An efficient synthesis of bis(indolyl)methanes and di(indolyl)indolin-2-ones has been developed by a sequential approach involving gold(I)-catalyzed cycloisomerization/bis-addition of o-ethynylanilines with various aldehydes and isatins, respectively. This methodology opens clean and synthetically competitive alternative to the already established procedures of the synthesis of bis(indolyl)methanes and di(indolyl)indolin-2-ones.     

Difunctional heterocycles: A convenient one pot synthesis of novel bis(benzoxazoles) from bis(o-aminophenols)

New bis(benzoxazoles) 14 and 17 have been synthesized in excellent yields from the corresponding bis(o-aminophenols) by refluxing with triethyl orthoformate. 6,6′-Bis(benzoxazole) ( 14 ) has also been prepared utilizing Gold's reagent. Compound 14 is inert to Reissert reaction conditions. However, the Reissert reaction on 5,5′-bis(benzoxazole) (17) led to ring opened product 20 .     

Synthesis, molecular and crystal structure, and features of the electronic structure of bis(O’i)-chelated bis(2,2-dimethylbenzo-[2H]-4-oxo-1,3-oxazino-3-methyl)difluorosilane

A method has been developed for the synthesis of a bis(O→Si)-chelated bis(2,2-dimethylbenzo[2H]-4-oxo-1,3-oxazino-3-methyl)difluorosilane from 2,2-dimethyl-3-trimethylsilylbenzo[2H]-1,3-oxazin-4-one and bis(chloromethyl)dichlorosilane via the intermediate formation of the corresponding unstable bis-chelated dichloride, subsequent hydrolysis with NaHCO₃ and, without separation, treatment of the hydrolysis product with boron trifluoride etherate. Analysis of the electron density distribution showed the presence of dative bonding in both O→Si-F fragments. Dedicated to Prof. Edmunds Lukevics on the occasion of his 70th birthday __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1866–1879, December, 2006.     

Isotope exchange study of bis/diethyl dithio carbamate/cadmium/II/ complex

Isotope exchange behaviour of bis/diethyl dithio carbamate/cadmium/II/ complex has been studied at 25°C and 35°C varying the concentrations of both metal ion and the complex. The results show that the complex is kinetically labile and the concentration has a significant effect on the rate of the reaction. Increase in temperature also effects the rate of exchange.     

(2-Pyridylmethyl)ammonium pyridine-2-carboxylate: the product of oxidative degradation of bis(2-pyridylmethyl)amine

The title compound, C₆H₉N₂⁺·C₆H₄NO₂⁻, has been formed by oxidative degradation of neat bis(2-pyridyl­methyl)­amine. Hydro­gen bonds link the ions into infinite chains along the a axis.     

The radiolysis of aqueous solution of bis/1,2-dicarbollyl/cobalt/III/ acid

The radiation-induced oxidation of bis/1,2-dicarbollyl/cobalt/III/ acid by OH radicals in deaerated/aerated aqueous solutions has been investigated. 8-Monohydroxy-, and 8,8-dihydroxy-derivatives have been identified as products of the -radiolysis. For the different conditions the following radiationchemical yields were observed: in the presence of N₂ atmosphere G/_OHDCC/=1.58, in aerated solution 2.11 and 3.04 in a solution saturated with CCl₃.