REGIOSELECTIVITY OF METALATION OF 1,3-DITHIOLANES AND 1,3-DITHIOLANE 1-OXIDES

Abstract

Deprotonation of 1,3-dithiolane 1-oxide (3) and trans-2-phenyl-1,3-dithiolane 1-oxide (5) leads to cleavage of the derived anions. Cleavage reactions do not occur with trans-hexahydro-1,3-benzodithiole (7), its 1-oxide, or its 1,1-dioxide all of which can be metalated and alkylated quantitatively at C-2. The preparation and reactions of the sulfoxides derived from 7 are not highly stereoselective.     

ADDUCTS FROM 2, 3-DIARYL-5-PHENYLMETHYLENE-4-OXO-1, 3-THIAZOLIDINE-1-OXIDES

Abstract

5-Phenylrnethylene-2, 3-diaryl-4-oxo-1,3-thiazolidine-1-oxides 2 which synthesised via peracetic acid oxidation of the respective 1, 3-thiazolidines 1 reacted with benzylamine and Grignard reagents to afford the respective 5-α-substituted benzyl-2, 3-diaryl-4-oxo-1,3-thiazolidine-l-oxides 3 and 4. Structures of 3 and 4 were based on analytical and spectral evidence.     

A FLUOROGENIC ACTINOMETER FOR NUCLEIC ACID PHOTOCHEMISTRY UTILIZING 1-DEAZAPURINE N(3)-OXIDES

A convenient and very sensitive actinometery system for UV radiation with wavelengths in the range250–310 nm is described, which is based on the fluorogenic photorearrangement of 1-deazapurine N(3)-oxide. The product, 1-deazapruin-2-one, can be estimated fluoremetrically in the presence of the N-oxide of 1-deazapurine and 1-methyl-1-deazapurine fail in the range 0.13-0.15 and do not vary significantly with wavelength. There is potential for using 1-deazupurine N(3)-oxides as UV-photoactivable fluorophores.     

A FACILE METHOD FOR DEBROMINATION OF VICINAL DIBROMIDES

In the presence of equimolar triethylamine,vicinal dibromideswere found to be easily debrominated by dibutyl telluride,forming the co-rresponding olefins.     

PHOSPHORUS-NITROGEN COMPOUNDS. PART 52.1 THE SYNTHESIS OF SOME 1,3,2-BENZODIAZAPHOSPHORINE 2-OXIDES AND 2-SULPHIDES

Abstract

The reactions of 4-methyl-2-[N-(p-toluidinyl)methyl]aniline with phosphorus oxychloride, thiophosphoryl chloride, and their derivatives yield 1,3,2-benzodiazaphosphorine 2-oxides and 2-sulphides. Their ¹H NMR and infrared spectra are discussed. Related 1,3,2-benzodiazophosphorine and 1,3,2-dibenzodiazaphosphocine 2-oxides and 2-sulphides are compared.     

CYCLIC ORGANOPHOSPHORUS COMPOUNDS. PART XVI1. MASS SPECTROMETRIC FRAGMENTATION OF SOME 5,5-DIMETHYL-1,3,2-DIOXAPHOSPHORINAN 2-OXIDES AND 2-SULPHIDES

Abstract

The mass spectra of seventeen 5,5-dimethyl-1,3,2-dioxaphosphorinan 2-oxides and nineteen 5,5-dimethyl-1,3,2-dioxa-phosphorinan 2-sulphides, mostly with amino substituents on phosphorus, have been determined. In some cases, interpretation of the spectra was aided by accurate mass measurements and by the examination of deuterated compounds. For the 2-sulphides, sulphur is lost either as such or as the thiol radical, both processes often being of weak intensity, and the thiol hydrogen appears to be derivable from either a ring methylene group or a C-5 methyl group. Loss of S or HS occurs more strongly for the phosphoramidothionates which, together with the phosphoramidates, also fragment to an important extent in the amido substituent with retention of the dioxaphosphorinan ring; P[sbnd]N bond cleavage is also observed. For the 2-thiones, the ions at m/e 165 (14; R[dbnd]H) and 133 (15; R[dbnd]H) are characteristic.     

ANISOTROPIC STRAIN EFFECT ON MORPHOLOGY AND ATOMIC STRUCTURE OF VICINAL Si(001) SURFACE

On vicinal Si(001) surfaces, dependence of growth morphology on the applied strain direction and formation of vacancy lines from Ag-induced missing dimer vacancies are studied. Both phenomena are intimately related to the anisotropic nature of the strain field which originates from the surface dimerization. Strain relief mechanism, reflecting on the surface morphology, is shown to be different in two orthogonal directions. Normal to the steps, step-pair bunching and waving lead to formation of hillocks and pits. Along the step direction, bending of step pairs forms a cusp which later develops into a deep groove. Toward the atomic scale, the formation of the vacancy lines is driven by the short-range attractive interaction between the vacancies in adjacent dimer rows and the long-range repulsive interaction between them in the same dimer row. A full form and magnitudes of the interactions are derived from the thermally-excited wandering of the vacancy lines formed by a nominal amount of Ag depositing onto the surface.     

新显色剂二溴对甲基偶氮氯磺光度法测定铅的研究及应用

研究了铅与新显色剂二溴对甲基偶氮氯磺的显色反应,在 0.08mol~(-1)·L~(-1)的高氯酸介质中铅与二溴对甲基偶氮氯磺形成稳定的蓝色络合物,最大吸收波长为634nm.表观摩尔吸光系数ε=1.01×10~5L·mol~(-1)·cm~(-1),铅量在0～30μg/25ml内符合比耳定律.方法应用于铜合金中微量铅的测定,结果满意.     

STUDIES ON STEROIDAL PLANT GROWTH REGULATOR 24. STEREOCONTROLLED CONSTRUCTION OF THE SIDE CHAIN OF BRASSINOLIDE AND HOMOBRASSINOLIDE VIA A TANDEM VICINAL DIALKYLATION OF PYRANONE MOIETY

A stereocontrolled construction of the side chain of brassinclide and homobrassinolide has been achieved via the tandem vicinal dialkylation of the pyranone moiety as a key step.     

THE INTERACTIONS BETWEEN PERIPHERAL AND CENTRAL UNITS IN SUPRAMOLECULAR AND METALLOSUPRAMOLECULAR STRUCTURES: THE CHARACTERIZATION OF SOME MONO-, DI- AND TRINUCLEAR COMPLEXES OF A VICINAL OXIME-IMINE LIGAND

Abstract

The 1:1 molar ratio reaction of p-phenylenediamine with isonitrosoacetylacetone in chloroform led to the formation of the half unit ligand (HL); (1). Two types of the trans octahedral (L)₂Ni 2H₂O complex were characterized; the green molecular complex (2) and the associated supramolecular dark brown complex (3). Molecular association in (3) took place via inter-molecular hydrogen bonding between the amino group of a molecule and the oxygen sites of an adjacent molecule. The 1:1 molar ratio reactions of (2) with the metal acetates M(OAc)₂ (M = divalent nickel, copper or cobalt) produced the self-assembly structure (4) whereby the metal acetate is coordinated to the amino groups of the nickel(II) complex. Reaction of the dinuclear (4) with another metal acetate (1:1 molar ratio) gave the trinuclear terminated structure (5). Similar reactions of (3) with nickel acetate (1:1 or 1:2) led to formation of complexes with metallosupramolecular structures. An antiferromagnetic interaction between the peripheral and central paramagnetic units was observed from those complexes with copper(II) at the peripheral location. In all these cases the metal ions are bridged via the aromatic Schiff-base moiety. The suggested structures of the mono-, di- and trinuclear coordination compounds are in accordance with the analytical, spectral and magnetic moment data.     

1-Phenyl-1-halo-1-silacyclohexanes

The approaches to synthesis of 1-phenyl-1-halo-1-silacyclohexanes C₅H₁₀Si(Ph)X (X = F, Cl, Br) have been examined. 1-Phenyl-1-chloro-1-silacyclohexane has been prepared via the known reaction of phenyltrichlorosilane with dimagnesium derivative of 1,5-dibromopentane; up to 20% of 1-bromo-1-phenyl-1-silacyclohexane admixture is formed along with the target product. The minor product formation has been prevented using an alternative method of chlorination of 1-phenyl-1-silacyclohexane with N-chlorosuccinimide. 1-Phenyl-1-fluoro-1-silacyclohexane has been obtained in close to quantitative yield via the reaction of 1-phenyl-1-chloro-1-silacyclohexane with SbF₃ and in 70% yield via its reaction with HF. The synthesis of 1-phenyl-1-bromo-1-silacyclohexane via bromination of 1-phenyl-1-chloro-1-silacyclohexane with N-bromosuccinimide has given the target product as a minor one, the major product being disiloxane formed due to hydrolysis of the Si–Br bond.     

Nuclear-substituted 1-phenyl-1-methyl-1-silacyclobutane derivatives

Conclusions The synthesis of some nuclear-substituted derivatives of 1-phenyl-1-methyl-1-silacyclobutane by the reaction of 1-methyl-1-chloro-1-silacyclobutane with the appropriate arylmagnesium bromides was described.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1686–1688, July, 1978.     

1-Methyl-1-ethynylsilacyclopentane

Conclusions We synthesized 1-methyl-1-ethynylsilacyclopentane, which is the first reported 1-ethynylsilacycloalkane. The reactivities of this silahydrocarbon and its magnesium bromide derivative were studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1403–1406, June, 1987.     

1-Chlor-1-phosphirane

The title compounds are prepared by reaction of disubstituted diazomethanes with 1-chloro-2-phenyl-2-trimethylsilyl-1-phosphaalkene. The chemistry of the 1-chloro-1-phosphiranes is described.