TRIALKYL PHOSPHITES DIRECTLY CONVERTED TO DIALKYL ALKYLPHOSPHONATE IN THE ABSENCE OF ALKYL HALIDES

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KINETIC STUDY OF THE REACTIONS OF TRIARYLPHOSPHINES WITH α-HALO SULFONES

Abstract

Reaction of a series of triarylphosphines with α-halo-m-cyanobenzyl phenyl sulfones gives the following Hammett ρ values: (CI) ρ = ?1.84; (Br) ρ = ?3.03; (I) ρ = ?3.36.     

THE THEORETICAL STUDIES OF PRODUCT ALIGNMENT OF THE REACTIONS OF Na,F WITH CH_3I

The NaI and IF product rotational alignment of the reactionsof Na,F+CH_3I has been theoretically studied in a LEPS PES.Theproduct alignment versus the relative translational energy of the reactantshas been obtained.     

A THEORETICAL STUDY OF MECHANISMS IN THE PHOTOCHEMICAL REACTIONS OF FORMING XETENE AFTER THE α-EOND RUPTURE IN CYCLCHEMANONE

ab initio,SCF+CI calculations of the potential energy surfaces and barries in the various paths are presented for the chemical reactions of forming ketene after the a-bond rupture in cyclohexanone,using acetaldehyde as model.The possibilities of the various paths and thansition states of the important paths are discussed.     

A STUDY OF THE REACTIONS OF BENZYL ETHERS WITH DIBROMOCARBENE

Using potassium carbonate as base and a polyethylene glycol with an average molecular weight of 600 (PGE600) as phase transfer catalyst, reaction of benzyl ethers with dibromocarbene leads to benzylic C—H bond insertion products, aromatic aldehydes are also formed as one of the products.     

REACTIONS WITH PHOSPHACUMULENES: SYNTHESIS OF PYRAN DERIVATIVES FROM THE REACTION OF N-PHENYLIMINOKETENYLIDENE TRIPHENYL-PHOSPHORANE WITH α,β-UNSATURATED CARBONYL COMPOUNDS

Abstract

2-Benzylidene-1,3-indanedione (2), 4-benzylidene-1,2-diphenyl-3,5-pyrazolidenedione (4) and/or 5-benzylidenebarbituric acid (6) can be converted by reaction with N-phenyliminoketenylidene triphenylphosphorane (1) into pyransubstituted phosphoranes 3, 5 and 7. The structure of the new cyclic imino-phosphoranes 3, 5 and 7 was confirmed on the basis of elemental analysis and spectral studies. Moreover, when Wittig reaction was carried out on the pyran compound 7, using p-nitrobenzaldehyde, the new olefin 8 was isolated.     

THE STUDY ON TRE KINETICS AND MECHANISM OF THE REACTIONS OF METAL IONS WITH PnAO

The kinetics and the mechanism of the formation reactions ofM(PnAO)~(2+)(M=Ni,Co,Cu)were studied with UV Spectrophotometer and StoppedFlow Spectrophotometer and a three steps mechanism was suggested.     

STUDIES ON THE CONSTITUENT OF THE ACTIVE COPPER CATALYSIA IN CYCLOPROPANATION REACTIONS

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CHEMISTRY OF DENUDATINE I. THE REACTIONS OF DENUDATINE AND DIACETYLDENUDATINE WITH NBS-HOAc

The reactions of denudatine 1 and diacetyldenudatine 2 with NBS-50% HOAc soln. afforded 4 and 6, respectively, in high yields.Treatment of 6 with (Ac)_2CO-Pyr. gives 7. The structures of 3,6 and 7 were deduced on the basis of spectral and chemical methods.     

THE USE OF MALONONITRILE IN THE SYNTHESIS OF NOVEL α-AMINO NITRILES

Continuing earlier studies designed to obtain compounds of pharmaceutical interest, we used acetyl acetone (1, R=CH₃) and ethyl acetoacetate (1, R=OEt) for the preparation of some novel α-amino nitriles (3, 6 and 7). The structures of the new ring systems have been confirmed by IR, NMR and mass spectral data.     

THERMAL AND PHOTOCHEMICAL REACTIONS BETWEEN α, α′-DIBROMOKETONES AND FIVE-MEMBERED HETEROCYCLES IN THE PRESENCE OF IRON NONACARBONYL

Abstract

[3 + 4] Cycloaddition reactions of 2-oxyallilic cations to furan¹ to form seven-membered oxobicyclic compounds have been known for some time. The purpose of this paper has been to try to extend the reaction to five-membered heterocycles with more aromatic character than furan. An analogy has been found between the behavior of thiophene, selenophene and tellurophene in these reactions and in oxetane-forming reactions. The higher the aromaticity of the heterocycle, the more difficult it is to achieve the formation of the seven-membered ring. Contrary to what is observed in oxetane-forming reactions, where it is not possible to isolate a stable tellurium compound, the tellurabicyclic compound was isolated and identified by spectroscopic methods in the present investigation.     

FACTORS INFLUENCING THE LOADING OF SUPPORTED MATERIAL IN THE PREPARATION OF Fe/TiO_2 CATALYSTS

The impregnations of different kinds of titania support with aqueous solution or ferricions at various pH values and with the solution of these ions in a polar aprotic solvent,dimethylformamide(DMF),were invcstigated.The results suggest that the surface ofhydrated titania is amphoteric,and has the function of a cationic exchanger,its ion ex-change properties arc dependent on the pH of the impregnating solutions.The higher theconcentration of metal ions in the impregnating solution and the more polar thc solvent,thehigher the loading on the support material having thc higher degree of crystallinity and alarger surface area without any pretreatments such as dehydration and calcination.     

REACTION OF M-DIMETHOXYBENZENE WITH CROTONIC ACID IN THE PRESENCE OF PPA

The reaction of m-dimethoxybenzene with crotonic acid in the presence of PPA affords anunexpected compound,which has been proved to be a dimer by H-NMR and MS.The x-ray struc-tural analysis has the same result.The phenomenon has not been reported.     

A FACILE AND NEW METHOD FOR THE SYNTHESIS OF α-ARYL-N-METHYLNITRONES IN SOLVENT-FREE MEDIA USING SILICA GEL-NaOH

Substituted α-aryl-N-methylnitrones are prepared by the condensation reaction of N-methylhydroxylamine hydrochloride and benzaldehydes in solvent-free media using silica-gel–NaOH catalyst system. The yields are excellent regardless of the electron-donating or electron-accepting nature of the substituents on benzaldehyde. Similar ketones are unreactive under these conditions, rendering chemoselectivity of the method.     

THE REACTION OF O-SILYLATED α-KETOLS WITH TRIMETHYLSILYL CYANIDE

Abstract

The reactions of a series of O-silylated α-ketols with trimethylsilyl cyanide have been investigated. Formation of the expected 0-trimethylsilyl cyanohydrins as major products has been shown to be accompanied by the hitherto unsuspected formation of a disiloxane by a proposed intramolecular S_N2 displacement mechanism. The latter reaction is, surprisingly, independent of the substitution pattern in the silylated ketol. Formation of the side-product, however, increases in all cases with increasing dilution. The α,β-epoxynitrile 9, a second side-product expected, along with the observed disiloxane, by our proposed mechanism was synthesized by an unambiguous route. A control experiment showed the epoxynitrile to be completely destroyed under the usual conditions of reaction with trimethylsilyl cyanide. ¹³C NMR data have been obtained for most of the compounds in this study.     

REACTIONS OF ORGANODILITHIUM COMPOUND WITH ALKYL HALIDES

The mechanism of the electron transfer reaction of 1,4-dilithio-tetraphenyl-1,3-butadiene with methyl iodide was studied.     

DEHYDROCHLORINATION OF α-CHLORO SULFONES WITH KOH-T-BUOH: KINETIC VS EQUILIBRIUM CONTROL OF THE FORMATION OF α, β-UNSATURATED SULFONES AND THE β-T-BUTOXY AND β-HYDROXY MICHAEL ADDUCTS

Abstract

Inorganic sulfur compounds are used by microorganisms (bacteria, fungi, algae) and plants for assimilation, i.e. biosynthesis of sulfur-containing cell constituents.

Quantitatively, within the biogeochemical cycle of sulfur the utilization of inorganic sulfur compounds in bacterial energy metabolism, i.e. dissimilatory sulfur utilization, is of far higher importance. Reduced sulfur compounds serve as electron donors for photosynthesis and respiration, whereas inorganic sulfur compounds of oxidation levels above sulfide serve as electron donors in anaerobic respiration as well as in fermentation. In still other bacteria reduced sulfur compounds act as protective agents against hydrogen peroxide.     

THE SYNTHESES OF POLYQUINOLINES WITH 2,2''''-PYRIDYLQUINOLINE AND 2,6-DIQUINOLYLPYRIDINE AS LIGAND AND THEIR APPLICATIONS IN SOME CATALYTIC REACTIONS

The polyquinolines with 2,2'-pyridylquinoline as bidentate and 2,6-diquinolylpyridine as tridentate ligand have been prepared from 4,4-dlamino- 3,3'-dibenzoyldiphenyl ether, 4,4'-diacetyldiphenyl ether and 1,4-bis (2-acetylpyridyl-6-oxy) benzene, 2,6-diacetylpyridine, respectively. These polyquinoline-supported ligands have been used in hydrogenation and hydroformylation of olefins with some transition metal complexes.     

REACTION OF α-CHLOROTOLUENE WITH ELEMENTAL SULFUR IN LIQUID AMMONIA

Abstract

α-Chlorotoluene (1) reacts with elemental sulfur in liquid ammonia affording dibenzyl disulfide (2), dibenzyl trisulfide (3), dibenzyl tetrasulfide (4), dibenzyl pentasulfide (5) and benzylidene benzylimide (6) at a low temperature such as 20°C. This reaction is presumed to be initiated by the nucleophilic attack of ammonium thioaminohydroxylate, “H₂NS^-NH₄ ⁺,” or dithioaminohydroxylate, “H₂NSS^-NH₄,” formed upon treating elemental sulfur in liquid ammonia, on α-chlorotoluene (1). Benzylidene benzylimide (6) is presumed to be formed from benzylamine, which can be formed by treatment of α-chlorotoluene (1) with ammonia.     

ON THE SYMMETRY ANALYSIS OF CHELETROPIC REACTIONS

By means of local symmetry analysis, the energy correlation diagrams of cheletropic reactions are built up by use of conventional quantum chemistry method to give the Woodward-Hoffmann rules.