Enantiopure 1-phosphanorbornadiene-2-carboxaldehydes

The reaction of phenylpropargyl aldehyde diethyl acetal with 1-phenyl-3,4-dimethylphosphole at 140°C or 1,2,5-triphenylphosphole at 170°C leads, after deprotection, to the corresponding 1-phosphanorbornadiene-2-carboxaldehydes 3 and 4 in 88 and 45% yields, respectively. The resolution of 3 and 4 was carried out by chromatography or fractional crystallization of the acetals derived from (S,S)-1,2-diphenylethane-1,2-diol. The absolute configurations were established by X-ray analysis of one of these acetals or of a 2-bromomethyl derivative.     

A novel synthesis of 5-acylaminooxazoles

1,2-Diacylamino-1,2-di(benzotriazol-1-yl)ethanes 2 , easily prepared from the condensation of 1,2-di(benzotriazol-1-yl)ethane-1,2-diol (1) and primary amides, were converted to 5-acylaminooxazoles in good to moderate yields via intramolecular cyclization upon treatment with sodium hydride.     

Claisen rearrangement of allyl phenyl ether and its sulfur and selenium analogues on electron impact

The electron impact (EI) mass spectrum of allyl phenyl ether (1) includes an ion at m/z 106 that is formed mainly by the loss of CO from the molecular ion, as supported by high resolution and MS/MS data. The formation of the [M - CO](+) ion from 1 can be explained in terms of the Claisen rearrangement of 1 after ionization in the ion source of the mass spectrometer. Similarly, allyl phenyl sulfide (2) and allyl phenyl selenide (3) showed characteristic ions corresponding to [M - CH(3)](+), [M - XH](+) (X = S or Se) and [M - C(2)H(4)](+.), and the formation of these ions are explained via Claisen rearrangement of 2 and 3 in the ion source of the mass spectrometer resulting in a mixture of rearrangement products. The formation of molecular ions of 2-allyl thiophenol and 2-allyl selenophenol as intermediates, that cannot be isolated as the neutrals from the solution phase Claisen rearrangement of 2 and 3, respectively, is clearly indicated in the gas phase. The mass spectra of the rearrangement products obtained from the solution phase reaction were also consistent with the proposal of formation of these products in the ion source of the mass spectrometer. The formation of characteristic fragment ions attributed to the Claisen rearrangement products are also evident in the collision induced dissociation spectra of the corresponding molecular ions. Copyright 2000 John Wiley & Sons, Ltd.     

Synthesis and Structure of New 2-(2-Quinolyl)-1,3-tropolone Derivatives

4,6-Di-tert-butyl-3-nitro-1,2-benzoquinone reacts with substituted 2-methylquinolines to give the corresponding 2-(2-quinolyl)-4-nitro-1,3-tropolones and 2-(2-quinolyl)-1,3-tropolones.     

Investigations on 2,3′-Biquinolyl. 16. The Regioselectivity of Reduction of 1-Alkyl-3-(2-quinolyl)quinolinium and 1,1′-Dialkyl-3,3′-di(2-quinolyl)-1,1′,4,4′-biquinolyl Iodides Using Metallic Zinc,Lithium and Potassium

The reaction of 1-alkyl-3-(2-quinolyl)quinolinium iodides with excess zinc in THF gives a diastereomeric mixture of 1,1′-dialkyl-3,3′-di(2-quinolyl)-1,1′,4,4′-tetrahydro-4,4′-biquinolyls. An excess of lithium in THF gives a mixture of 1′,2′-dihydro-2,3′-biquinolyl and 1′-alkyl-1′, 4′-dihydro-2,3′-biquinolyl with the former predominating. The reduction by lithium in THF of 1,1′-dialkyl-3,3′-di(2-quinolyl)-1,1′,4,4′-tetrahydro-4,4′-biquinolyls leads to analogous products. Reduction of 1-alkyl-3-(2-quinolyl)quinolinium iodides by metallic potassium gives 1-alkyl-1′,4′-dihydro-2,3′-biquinolyls. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1208–1212, August, 2005.     

Molecular and crystalline structure of 2,2-di(phenyl-4-ol)propane dimethacrylate, 2,2-di(phenyl-4-ol)propane diacrylate,pyrocatechol diacrylate,and hydroquinone diacrylate: Reactivity in melts

The X-ray diffraction analysis of 2,2-di(phenyl-4-ol)propane dimethacrylate, 2,2-di(phenyl-4-ol)propane diacrylate, pyrocatechol diacrylate, and hydroquinone diacrylate has shown that oligomer molecules within crystals are packed in stacks, where (meth)acrylate fragments of neighboring molecules are parallel to each other. The minimum distances between the centers of double bonds C=C of (meth)acrylate fragments in 2,2-di(phenyl-4-ol)propane dimethacrylate, 2,2-di(phenyl-4-ol)propane diacrylate, pyrocatechol diacrylate, and hydroquinone diacrylate are 4.208, 4.012, 3.621, and 3.739 describing the reduced rate of photopolymerization of molten monomers (with 9,10-phenanthrenequinone used as a photoinitiator) versus conversion show maxima at degrees of polymerization of 8, 16, 22, and 38%; the limiting conversions are 29, 36, 44, and 86%, respectively. The maximum reduced rates of photopolymerization of 2,2-di(phenyl-4-ol)propane dimethacrylate and diacrylate are nearly the same, whereas the rates of photopolymerization of hydroquinone diacrylate and pyrocatechol diacrylate are higher by a factor of 4 than those of the corresponding dimethacrylates.     

Characterization of isomeric allylic diols resulting from chlorophyll phytyl side-chain photo- and autoxidation by electron ionization gas chromatography/mass spectrometry

The electron ionization (EI) mass spectral fragmentation of the trimethylsilyl derivatives of 3-methylidene-7,11,15-trimethylhexadecane-1,2-diol, Z- and E-3,7,11,15-tetramethylhexadec-3-ene-1,2-diols and Z- and E-3,7,11,15-tetramethylhexadec-2-ene-1,4-diols resulting from chlorophyll phytyl side-chain photo- and autoxidation was investigated. Different pathways (substantiated by deuterium labelling) were proposed in order to explain the main fragmentation observed. Then, some sufficiently specific fragment ions were selected and used to characterize these compounds in natural environmental samples.     

The investigations in 2,3′-biquinoline series. 25*. Synthesis of 4-(2-quinolinyl)-pyrrolo[1,2-<Emphasis Type="Italic">a</Emphasis>]quinolines and 4-(2-quinolyl)-imidazo[1,2-<Emphasis Type="Italic">a</Emphasis>]quinolines

A method has been developed for the synthesis of 4-(2-quinolinyl)-1,2,3,3a-tetrahydropyrrolo-[1,2-a]quinolines based on the 1,3-dipolar cycloaddition reaction of α,β-unsaturated carbonyl compounds to 2,3′-biquinolinium salts. Oxidation in benzene using MnO₂ gave 4-(2-quinolinyl)-pyrrolo[1,2-a]quinolines. It was found that a side product of the 1,3-dipolar cycloaddition is 7,14-di-benzoyl-6,13-di(2-quinolyl)-6a,7,13a,14-tetrahydro-7a,14a-diazadibenzo[a,h]anthracene. Reaction of 1′-phenacyl-2,3′-biquinolinium salts with hydroxylamine in acetic acid gave 4-(2-quinolyl)imidazo-[1,2-a]quinolines. *For Communication 24 see [1]. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 433–439, March, 2009.     

Synthesis of analogs of amrinone: 4-(3,4-Disubstitutedphenyl)pyridines and derivatives thereof

4-(3,4-Dimethoxyphenyl)pyridine ( 5c ) prepared by the coupling of 3,4-dimethoxyphenyldiazonium chloride with pyridine was converted to 4-(4-pyridinyl)benzene-1,2-diol ( 6c ) by treating with hydrobromic acid. Diazotization of 4-(4-pyridinyl)benzeneamine ( 7 ) and 3-(4-pyridinyl)benzeneamine ( 12 ) gave the corresponding phenols 8 and 13 which were nitrated to give 2-nitro-4-(4-pyridinyl)phenol ( 9 ) and 2-nitro-5-(4-pyridinyl)-phenol ( 14 ), respectively. Reduction of these nitrophenols gave the corresponding aminophenols 10 and 16 which in turn were reacted with N,N'-carbonyldiimidazole to yield benzoxazolones 11 and 17 , respectively. Catalytic reduction of 2-nitro-4-(4-pyridinyl)benzeneamine ( 18 ) gave 4-(4-pyridinyl)benzene-1,2-diamine ( 19 ) which was reacted with orthoesters, urea, tetraethoxymethane, and N,N'-di(carbomethoxy)methylpseudothiourea to give the corresponding benzimidazole derivatives 20, 21, 22 , and 23 .     

New rearrangement in the adamantylation reaction of 4-iodophenol and 4-iodoanisole

A reaction of 2-iodophenol and 2-iodoanisole with 1-adamantanol in trifluoroacetic acid gives the corresponding 4-(1-adamantyl) derivatives. Similar adamantylation of 4-iodophenol and 4-iodoanisole is accompanied by migration of the iodine atom from para- to ortho-position, giving 4,6-di(1-adamantyl)-2-iodophenol and 4-(1-adamantyl)-2-iodoanisole, respectively, as the reaction products.     

Asymmetric Direct Aldol Reactions Catalyzed by a Simple Chiral Primary Diamine–Br⊘nsted Acid Catalyst in/on Water

Abstract

The direct asymmetric aldol reaction catalyzed by the simple and commercially available chiral primary diamines, (1S,2S)-1,2-diphenylethane-1,2-diamine and (1R,2R)-1,2-diphenylethane-1,2-diamine, is presented. The catalyst system is a primary amine with Br?nsted acid–catalyzed direct aldol reaction of p-nitrobenzaldehyde and cyclohexanone with high chemo- and stereoselectivity on water, which furnishes the corresponding β-hydroxyketone with up to 94% ee.     

Synthesis of 3,4-di(methylene)tetrahydrothiophene-1,1-dioxide and its use in organic synthesis

A convenient reaction scheme has been developed for obtaining 3,4-di(methylene)tetrahydrothiophene-1,2-dioxide from the readily available 3,4-dimethyl-2,4-dihydrothiophene-1,1-dioxide through 3,4-di(bromomethyl)-2,5-dihydrothiophene-1,1-dioxide. A feasibility study has been made of the use of the butadiene fragment of the heterocycle in a Dieb—Alder reaction with maleic acid derivatives, and the corresponding adducts have been obtained.DeceasedTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 173–175, February, 1992.     

Synthesis of n-chloroquinolines and n-ethynylquinolines (n=2, 4, 8): homo and heterocoupling reactions

The n-(ethynyl)quinolines were satisfactorily prepared by heterocoupling reaction between the appropriate n-chloroquinoline and 2-methyl-3-butyn-2-ol, catalyzed by palladium, followed by treatment with a catalytic amount of powdered sodium hydroxide in toluene. The n-(ethynyl)quinolines were transformed in the corresponding conjugate 1,4-bis[n′-(quinolyl)]buta-1,3-diynes by oxidative dimerization, catalyzed by cuprous chloride, with excellent yields. Moreover, the heterocoupling between n′-haloquinoline and n′-(ethynyl)quinoline (n′, 2′ or 3′), catalyzed by palladium, gives 2′,2′-bis(quinoline) or 1,2-di(3′-quinolyl)ethyne, respectively. The same coupling reaction with zerovalent nickel complexes, gives a mixture of 1,2,4- and 1,3,5-tri(n′-quinolyl)benzene.     

Synthesis, structure, and photoisomerization of derivatives of 2-(2-quinolyl)-1,3-tropolones prepared by the condensation of 2-methylquinolines with 3,4,5,6-tetrachloro-1,2-benzoquinone

A series of novel derivatives of the 1,3-tropolone (β-tropolone) system—2-(2-quinolyl)-5,6,7-trichloro-1,3-tropolones and 2-(2-quinolyl)-4,5,6,7-tetrachloro-1,3-tropolones have been prepared by the acid-catalyzed reaction of 2-methylquinolines with 3,4,5,6-tetrachloro-1,2-benzoquinone. The molecular structures of two compounds, 2-(4-chloro-6,8-dimethyl-5-nitro-2-quinolyl)-5,6,7-trichloro-1,3-tropolone 8 and 2-(4-chloro-7,8-dimethyl-5-nitro-2-quinolyl)-4,5,6,7-tetrachloro-1,3-tropolone 9, have been determined using X-ray crystallography. According to the performed DFT B3LYP/6-311++G^∗∗ calculations the tautomeric (OH) and (NH) forms of β-tropolones 8 and 9 are nearly energy equivalent, the latter being more stabilized in polar media. Photolysis of 2-(2-quinolyl)-1,3-tropolones in heptane solution leads to the disrotatory electrocyclic rearrangement resulting in the formation of a mixture of E- and Z-isomers of 3-[2(1H)-quinolinylyden]-bicyclo[3.2.0]hept-6-en-2,4-dione derivatives.     

Organophosphorus chemistry. Part 18. Possible intervention of a phospha-alkene in the reactions of a fluoroalkylphosphine with alkoxides

Thermal reactions of phenylphosphine with tetrafluoroethylene and 1,1-difluoroethylene give, respectively, a mixture of phenyl-1,1,2,2-tetrafluoroethylphosphine and 1,2-bis-(phenylphosphino)tetrafluoroethane, and phenyl-2,2-difluoroethylphosphine. The phenyltetrafluoroethylphosphine reacts with an excess of ethanolic or methanolic alkoxide to give the corresponding alkyl phenyl-($\text{E}$)-1-fluoro-2-alkoxyvinylphosphinite and minor amounts of the isomeric alkyl phenyl-($\text{Z}$)-2-fluoro-2-alkoxyvinylphosphinite. The use of an equimolar proportion of sodium methoxide enables the intermediate products methyl phenyl-1,2,2-trifluoroethylphosphinite and methyl phenyl-($\text{E}$)-1,2-difluorovinylphosphinite to be isolated: further reaction of these with methoxide yields the corresponding ($\text{E}$)-1-fluoro-2-methoxyvinylphosphinite. The reactions are discussed in terms of mechanisms which involve either an intermediate phospha-alkene or a hydride ion shift.     

New chiral metal complexes based on 2-ethoxymethylidene-3-oxo-3-polyfluoroalkylpropionates

Ethyl 2-ethoxymethylidene-3-oxo-3-polyfluoroalkylpropionates reacted with (1S,2S)-1,2-diphenylethane-1,2-diamine to give diethyl 2,2′-{[(1S,2S)-diphenylethane-1,2-diyl]bis[iminomethylidene]}bis(3-oxo-3-polyfluoroalkyl)alkanoates which were used as ligands to obtain chiral complexes with transition metals.     

Stereoselective synthesis of novel benzoins catalysed by benzaldehyde lyase in a gel-stabilised two-phase system

Asymmetric benzoin condensation was performed using recombinant benzaldehyde lyase (BAL) from Pseudomonas fluorescens Biovar I. To enable the conversion of hydrophobic substrates, the enzyme was entrapped in polyvinyl alcohol and suspended in hexane. Compared to the reported application of the biocatalyst in an aqueous phase containing 20% DMSO, the productivity of the resulting gel-stabilised two-phase system was 3-fold better. The entrapment process had an efficiency of >90%, no enzyme or cofactor was lost during reaction or storage. The entrapped enzyme was stable in hexane for 1 week at 4 °C and more than 1 month at −20 °C. Without preceding optimisation the novel benzoins (R)-1,2-di(3-furanyl)-2-hydroxyethanone, (R)-2-hydroxy-1,2-di(3-thienyl) ethanone, (R)-1,2-di(4-ethoxyphenyl)-2-hydroxyethanone, (R)-1,2-di(3-ethoxyphenyl)-2-hydroxyethanone, (R)-2-hydroxy-1,2-di(3-tolyl)ethanone, and (R)-1,2-di(benzofuran-2-yl)-2-hydroxyethanone were prepared with yields up to 31.8% and enantiomeric excess >99%.     

An approach to a chiral cycloalkanone-mediated asymmetric epoxidation of stilbene with oxone.

Chiral and C2-symmetric seven-membered cycloalkanones 2--6 bearing 1,2-diphenylethane-1,2-diamine and cyclohexane-1,2-diamine backbones were synthesized and evaluated their asymmetry inductive behaviours in an asymmetric epoxidation of stilbene with oxone. Although the reaction of the ketones 2 and 3 of a 1,2-diphenylethane-1,2-diamine backbone gave stilbene oxide in trace to 31% yield, those of the ketones 4-6 of a cyclohexane-1,2-diamine backbone gave the epoxide in satisfactorily high yield up to 98%. It is noteworthy that both reactions with use of stoichiometric and substoichiometric amounts of a ketone 4 gave the epoxide in the essentially same enantioselectivity, 17 and 18%. Eleven-membered cyclic ketones 7 and 8 bearing a binaphthalene backbone were also synthesized and examined their behaviours, while the enantioselectivity turned out to be marginal.     

Reaction of 4,4-Dimethyl-1,3-dioxane with Dinitriles

The reaction of 4,4-dimethyl-1,3-dioxane with bis(2-cyano)diethyl ether or 1,2-di(beta-cyanoethoxy)ethane yields the corresponding bis[2-(4,4-dimethyl-5,6-dihydro-2-oxazinyl)]diethyl ether and 1,2-di{beta-[2-(4,4-dimethyl-5,6-dihydro-2-oxazinyl)]ethoxy}ethane which are readily hydrolyzed under the action of aqueous alkali to give 3-methyl-3-amino-1-butanol.     

Cyclization of 1,1,2,2-tetracyanoethane by the semicarbazones and oximes of carbonyl compounds

1,1,2,2-Tetracyanoethane undergoes cyclization with semicarbazones and oximes with the formation of 5-substituted 2-amino-3,4,4-tricyano-N-ureido(N-hydroxy)-2-pyrrolines. When heated, the latter readily eliminate HCN, forming the corresponding 3,4-dicyano-N-ureidopyrroles. The reaction of the N-ureidopyrroles with benzaldehyde leads to 1,2-di(benzylidenamino)-3,4-dicyanopyrroles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1046–1051, August, 1991.