Sulphur substituted organotin compounds. Part 6. Reactions of mercaptomethyltin compounds with arenesulphenyl chlorides

Reactions between Ph₃SnCH₂SAr and 2-NO₂C₆H₄SC? lead to the formation of 2-(ArSCH₂-6-NO₂C₆H₃SSC₆H₄NO₂-2 via the [2,3]sigmatropic rearrangement of the S-arylthio-sulphonium ylides $\text{C}$H₂$\text{S}\text{+}$(Ar)SC₆H₄NO₂2.     

Reactions involving fluoride ion. Part XII. Reactions of polyfluoro-aromatic compounds with octafluorobut-2-ene

Octafluorobut-2-ene is much more difficult to dimerise, with fluoride ion, than is hexafluoropropene but perfluoro-3,4-dimethylhex-3-ene is obtained under more forcing conditions. In contrast, polyfluoroalkylations with octafluorobut-2-ene are very efficient and results with perfluoro-pyridine, -pyridazine, and -quinoline are described, giving various perfluoro-2-butyl derivatives. Reactions with nitropentafluorobenzene and perfluorotoluene are also described. The ¹⁹F n.m.r. spectra of perfluoro-2-butylaromatic compounds reveal restricted rotation, even at room temperature.     

Fluoro-ketones. II Reactions of fluorocarbon grignards and copper compounds with perfluoroalkylacid fluorides

The reactions between C₆F₅MgBr (I), p-BrC₆F₄MgBr (X), C₆F₅Cu (XXI), p-HC₆F₄Cu (XXII) and p-BrC₆F₄Cu (XV) with primary and secondary perfluoroalkylether acid fluorides were studied. The Grignard compounds react very slowly with the secondary acid halides (R_fCF(CF₃C(O)F) whereby competing reactions cause undesirable by-products and reduction of ketone yields. Primary acid halides (R_fCF₂C(O)F) react much faster with C₆F₅MgBr to give the ketone in improved yields. The organocopper compound react with either primary or secondary acid halides to give the ketone in excellent yields with no by-product formation from competing secondary reactions. Solvent, type of organometallic reagent and primary versus secondary acid fluoride are variables that influence product yield and product distribution.     

Photochemistry of ommochromes and related compounds. Part II

The visible light irradiated solutions of the 1-methyl-1-(1′-[11-(β-aspartoyl-methyl ester-imino)]ethenyl]-ketal-1H,5H-pyrido[3,2-a]phenoxazin-5-one ( 1 ) and the 1,5-dimethoxy-11-(β-aspartoyl-N-acetyl-methyl ester)-pyrido[3,2-a]phenoxazine ( 2 ) [1], in methanol and acidic methanol, are examined. Both methanolic solutions undergo light induced transformation according to an opening of the phenoxazinone and phenoxazine systems, not reversible in darkness. On the contrary, 1 and 2 in methanol-acid solutions, under visible light irradiation, yield a solvent photoaddition, reversible in darkness. Some phototransformation products are examined and a plausible mechanism, for the reactions explanation, is suggested.     

Reactions of cationic rhodium(I) carbonyl compounds with nucleophiles to form alkoxo,carboalkoxy and carboxylato complexes. Part II

Summary The rhodium(I) carbonyl compounds [Rh(CO)L₂2] [BF₄]. 1/2CH₂Cl_nn2 (L = PPh₂ or AsPh₃) react with the nucleophiles OMe⁻, RCOO⁻ (R = Me, Et) under nitrogen to form [Rh(OR)(CO)L₂] (1)–(2) and [Rh(OOCR)(CO)L₂] (7)–(₁₀), respectively. Addition of [Rh(CO)₂(PPh₃)₂]-[BF ₄] to OMe⁻ under nitrogen produces [Rh(COOMe)-(CO) (PPh₃)₂]-MeOH (3), whilst reactions of [Rh(CO)-(PPh₃)₂] [BF₄]·1/2CH₂Cl₂ and [Rh(CO)₂(PPh₃)₂] [BF₄] with OR_- (R = Me, Et or n-Pr) in the presence of CO produce [Rh(COOR)(CO)₂(PPh₃)₂] (4)–(6). The products have been characterised by i.r., ¹H, ³¹P, ¹³Cn.m.r. spectroscopy and elemental analysis.     

Phenoxyaluminium compounds : VII. Reactions of organoaluminium compounds with hindered phenols

Reactions of Me₃Al, i-Bu₃Al, Me₂AlCl and Me₂AlCCMe with 2,6-di-t-butyl-4-methylphenol have been studied at different molar ratios of the reactants.It is found that in the reaction with the phenol, trimethylaluminium forms monomeric methylaluminium diphenoxide; triisobutylaluminium gives both monomeric mono- and di-phenoxyaluminium (depending on molar ratios of the reactants) and dimethylchloroaluminium forms dimeric methylphenoxyaluminium chloride.It is found that methylpropynylaluminium phenoxide is unstable and disproportionates in hydrocarbon solutions.The mechanisms of some of these reactions are suggested.     

Reactions of a ruthenium(II) arene antitumor complex with cysteine and methionine

The Ru(II) organometallic antitumor complex [(eta(6)-biphenyl)RuCl(en)][PF(6)] (1) reacts slowly with the amino acid L-cysteine (L-CysH(2)) in aqueous solution at 310 K. Reactions were followed over periods of up to 48 h using HPLC, electronic absorption spectroscopy, LC-ESI-MS, and 1D or 2D (1)H and (15)N NMR spectroscopy. Reactions at a 1 mM/2 mM (Ru/L-CysH(2)) ratio were multiphasic in acidic solutions (pH 5.1) and appeared to involve aquation as the first step. Initially, 1:1 adducts involving substitution of Cl by S-bound or O-bound L-CysH(2), [(eta(6)-biphenyl)Ru(S-L-CysH)(en)](+) (4a) and [(eta(6)-biphenyl)Ru(O-L-CysH(2))(en)](2+) (4b) formed, followed by the cystine adduct [(eta(6)-biphenyl)Ru(O-Cys(2)H(2))(en)](2+) (3), and two dinuclear complexes from which half or all of the chelated ethylenediamine had been displaced, [(eta(6)-biphenyl)Ru(H(2)O)(microS,N-L-Cys)Ru(eta(6)-biphenyl)(en)](2+) (5) containing one bridging cysteine, and [(eta(6)-biphenyl)Ru(O,N-L-Cys-S)(S-L-Cys-N)Ru(eta(6)-biphenyl)(H(2)O)] (6) containing two bridging cysteines. The unusual cluster species [(biphenyl)Ru](8) (7a) was also detected by MS and was more prevalent in reactions at higher L-CysH(2) concentrations. Complex 5 was the dominant product at pH 2-5, but overall, only ca. 50% of 1 reacted with L-CysH(2) in these conditions. The reaction between 1 and L-CysH(2) was suppressed in 50 mM triethylammonium acetate solution at pH > 5 or in 100 mM NaCl. Only 27% of complex 1 reacted with L-methionine (L-MetH) at an initial pH of 5.7 after 48 h at 310 K and gave rise to only one adduct [(eta(6)-biphenyl)Ru(S-L-MetH)(en)](2+) (8).     

Reactions of cyclic oxalyl compounds,Part 30: Some reactions with N-amino-pyrimidine derivatives

Summary 1-Amino-5-benzoyl-4-phenyl-1H-pyrimidine derivatives1 add arylisocyanates2 to give the N,N-disubsituted ureas3 which can be cyclized by use of oxalyl dichloride to the imidazolyl-pyrimidinones(thiones)4. In addition,1 is transferred into the desaminated pyrimidines6 either by diazotation reaction or by thermolysis of the parental functionalized pyrimidine derivatives7.Dedicated to o. Univ. Prof. Dr. F. Sauter on the occasion of his 60th birthday     

Carbenoid reactions of trifluoromethylelement compounds. Part 4. Reactions of trifluoromethylzinc bromide with enamines and methylene bases

The reactions of ZnBr(CF₃)·2CH₃CN with 1-morpholinocyclo-pentene and -hexene have been investigated and found to yield mixtures of two isomers of 1-morpholino-1-cyanomethyl-2-difluoromethyl-cyclopentane and -hexane, respectively. The interaction with methylene bases of nitrogen heterocycles leads to the formation of trimethinecyanine dyes. This reaction sequence includes the formation of two carbon-carbon bonds in a one-pot operation. The mechanism of the reactions is discussed.     

Ion-association compounds of anionic surfactants with iron(II)chelates: Part II. Selective determination of surfactants

Homologous anionic surfactants may be separated from each other by solvent extraction of their ion-association compounds with iron(II) chelates. Separations of components from a number of surfactant mixtures were investigated, and the effect of solution variables on extraction and separation was studied. A method is proposed for the determination of surfactants of various chain lengths. Applications of this method to synthetic mixtures and to biodegradation experiments are described.     

Electrochemical cyclization of unsaturated hydroxy compounds. Part II. Phenylselenolactonization

Phenylselenolactonization was performed, in one step, by electrolysis of Δ4- and Δ5 -unsaturated carboxylic acids and diphenyl diselenide in methanol containing ammonium bromide.     

Reactions of copper(II) halides with aromatic compounds—IX: Reactions of 1- and 2-alkoxynaphthalenes

2-Alkoxynaphthalenes undergo halogenation with copper(II) halides in the 1-position though 2-benzyloxynaphthalene with copper(II) bromide gives additionally di-β-naphthol, 1-benzyl-2-naphthol, and benzyl bromide. The reaction of 1-alkoxynaphthalenes with copper(II) halides leads to 1-alkoxy-4-halogenonaphthalenes and 4,4′-dialkoxy-1,1′-binaphthyls. 8-Chloro-1-methoxynaphthalene is afurther product from the reaction of 1-methoxynaphthalene and copper(II) chloride. The reactions are postulated to proceed via the radical cation of the alkoxynaphthalene formed in an electron-transfer reaction. This can then either react further with the copper(II) halide or dimerize.     

半胱氨酸和谷胱甘肽氧化反应动力学的研究进展

本文对半胱氨酸和谷胱甘肽的氧化反应动力学的研究进展进行了综述。阐述了含硫氨基酸的生化性质、应用及其重要作用。分别对半胱氨酸、谷胱甘肽的氧化产物分析和动力学机理的研究成果进行了介绍。提出了巯基氨基酸及肽氧化反应动力学研究难点和可行的研究手段及方法。     

Polyfluoro-1,2-epoxy-alkanes and - cycloalkanes. Part II. Reactions of decafluoro-1,2-epoxycyclohexane

The epoxy ring of the title compound has been opened by nucleophilic attack using lithium aluminium hydride, sodium methoxide, methyl lithium, sodium azide and potassium cyanide. The primary product incorporated the nucleophile (N) and an alkoxy function, which was fixed by methylation when N = CN. However, in most cases the alkoxide group decomposed to carbonyl, and the ketone was isolated when N was OMe. More nucleophile could be added across this carbonyl group, the resultant substituted alkoxide being isolated as the tertiary alcohol (N = Me) or the methyl ether (N = N₃). With lithium aluminium hydride (N = H), a secondary alcohol was obtained, the fluorine on the ring carbon bearing the alkoxy group being replaced by H; the pathway probably did not involve a free carbonyl group, since the resultant alcohol was a pure stereoisomer. This was shown by nmr, and also since the pure methoxymethyl ether made from it was dehydrofluorinated exclusively to 2H-octafluorocyclohexenyl methoxymethyl ether.