Tele-substitution reactions in the naphthalene series : The behaviour of 1,4 - dimethyl - 2 - nitro - 3 - phenylsulphonyl - and 2,3 - bisphenylsulphonyl - 1,4 - dimethyl - naphthalene towards sodium arenethiolates and secondary aliphatic amines

1,4 - Dimethyl - 2 - nitro - 3 - phenylsulphonylnaphthalene (2) reacts with sodium benzenethiolate in DMSO at 120° to give 1 - methyl - 2 - nitro - 4 - phenylthiomethylnaphthalene (4) [tele-substitution product (TSP) of the phenylsulphonyl group] and 1,4 - dimethyl - 3 - phenylsulphonyl - 2 - phenylthionaphthalene (5) [normal substitution product (NSP) of the nitro group]. The analogous reactions of 2 with sodium 2,4,6- trimethylbenzenethiolate and of 2,3 - bisphenylsulphonyl -1,4 - dimethylnaphthalene (3) with sodium benzenethiolate or aliphatic amines give only TSPs of the phenylsulphonyl group. In the case of the reaction of 2 with aliphatic amines both the possible TSPs (tele-substitution of the phenylsulphonyl or of the nitro group) were isolated in 9:1 relative yield. All the data show that the phenylsulphonyl is a leaving group far better than the nitro in such tele-substitution processes. The mechanism previously proposed to account for the formation of TSPs from 1,4-dimethyl - 2,3 - dinitronaphthalene is strongly supported by the obtained results.     

Hydrierung prochiraler Olefine mit Rhodium-Komplexen von optisch aktiven Amidinen

[RhCl(C₈H₁₄)₂]₂ together with the optically active amidines C₆H₅C(=NR)NHCH(CH₃) (C₆H₅) I–V or their Li derivatives after activation with molecular hydrogen gives catalysts which at room temperature and 1.1 bar H₂-pressure hydrogenate the prochiral substrates (Z)-[N-acetylamino]-cinnamic acid, itaconic acid, -methylcinnamic acid, -methylcinnamic aldehyde, and -methylcinnamic alcohol as well as cyclohexene, benzene and toluene. Good hydrogenation activity of the new catalysts is in contrast to low optical induction which only in the hydrogenation of -methylcinnamic alcohol with 1.5 to 2% leads to values different from zero.

3. Mitt.:H. Brunner undW. Pieronczyk, J. Chem. Res., im Druck.     

Use of isothermal microcalorimetry data for the determination of integral molar entropies of adsorption at the gas—solid interface by a quasi-equilibrium procedure

The aim of this paper is to describe the present position in the experimental determination of entropies of adsorption. After pointing out the limitations of the “isosteric” approach and after stressing the fact that the most interesting entropy to know is the integral molar entropy of adsorption, the authors show how the use of isothermal adsorption microcalorimetry, with a special quasi-reversible procedure, allows this entropy to be determined satisfactorily from the thermodynamic point of view.     

Adducts of 2-aminothiophenol with acetylenic nitriles or esters and their conversion into benzothiazoles and/or 1,4-benzothiazines

The reaction between 2-aminothiophenol 1 and acetylenic nitriles or esters 2a-d leads to the vinyl thio-ethers 3a-d. The conversion of 3 into benzothiazoles 8 and/or 1,4-benzothiazines 9 , in boiling dimethyl sulfoxide, has been achieved. A possible pathway involving benzothiazolines 5 as key intermediates is suggested.     

On the supposed equilibrium Ph6Pb2Ph4Pb+Ph2Pb in solution

The reaction between pentadeuteriophenyllithium and hexaphenyldilead combined with new measurements of isotopic exchange between Ph₆Pb₂ (labelled with RaD) and Ph₄Pb, have shown that the dilead compound is undissociated in solution. These results cast doubt upon the previously reported equilibrium: Ph₆Pb₂Ph₄Pb+Ph₂Pb.     

Five-coordinate low-spin cobalt(II) complexes with benzeneseleninato ions and ethylenediamine as ligands

Summary Five-coordinate bis(benzeneseleninato)tris(ethylenediamine) cobalt (II)complexes are obtained by reaction of Co(H₂O)₂ (XC₆ H4 SeO₂)2 complexes (X = H, p-Cl, m-CI, p-Br, ni-Br, p-Me,p-NO₂) with ethylenediamine. The diaquo complexes (one mole)react with ethylenediamine (three moles)to form O-seleninato derivatives. Spectral and magnetic properties show that the complexes are low-spin (s = 1/2) and,on the basis of the electronic spectra a distorted trigonal geometry,D _3h , is suggested. Assignments for the electronic spectra are proposed. Conductivity data indicate that these derivatives are nonelectrolytes. Both ethylenediamine and [RSeO₂ ]^– behave as monodentate ligands.     

Azobenzene complexes of dicyclopentadienyltitanium and dicyclopentadienylvanadium

Reactions of azobenzene with dicarbonyldicyclopentadienyltitanium(II), Ti(π-C₅H₅)₂(CO)₂, and dicyclopentadienylvanadium(II), V(π-C₅H₅)₂, have yielded the corresponding dicyclopentadienylmetal-azobenzene complexes.     

The relative permittivity of 1,2-dimethoxyethane and N,N-dimethylformamide mixtures from −10 to 40°C

Binary solutions of N,N-dimethylformamide and 1,2-dimethoxyethane have been investigated by means of dielectric measurements at temperatures ranging from –10 to +40°C, and for nine mixtures covering the whole miscibility field expressed by the mole fraction of one component (0X₁1). The experimental data were used to study the dependence of on T and X₁, of the type = (T), = (X₁), and = (T,X₁). Further, the excess mixing function _E has been evaluated in order to identify particular patterns of interaction between unlike molecules and any other factor that could modify such patterns. The minimum in the _E vs. composition plots suggests the formation of an adduct of stoichiometric ratio DMFDME=11 at all the investigated temperatures.