Neues verfahren zur bestimmung der acetylgruppe

A simple and accurate method is described for the determination of acctyl groups in various organic compounds. The compound is dissolved or suspended in absolute methanol and saponified with a known quantity of potassium methylate solution. The excess potassium methylate is then hydrolysed and determined as potassium hydroxide by titration, an appropriate indicator being used.     

Indolopyridines with a bridging heteroatom

Reaction of 2-acetylpyridine with 4-[2.2]paracyclophanyllithium or 4-acetyl[2.2]paracyclophane with 2-pyridllithium gives 1-([2.2]paracyclophan-4-yl)-1-(2-pyridyl)ethanol. Its molecular and crystalline structures have been studied by x-ray analysis. It was found that heating this alcohol in acid medium causes dehydration and heterocyclization to give 1-paracyclophanyl-1-pyridylethylene and 10-methyl[2.2]paracyclophano[4,5-bindolizine.For communication 9 see [1]. This report is also communication [5] in the series Synthesis, Structure, and Biological Activity of [2.2]Paracyclophanes (for communication 4 see [2]).Russian University of National Friendship, Moscow 117198. A. N. Nesmeyanov Institute of Organoelemental Compounds, Russian Academy of Sciences, Moscow 117813. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 793–800, June, 1997.     

The vibrational spectra of maleimide and N-D maleimide

The infrared spectra of maleimide as a vapour (160°C), melt (100°C), oriented polycrystalline film, pellet and when dissolved in various solvents were recorded between 4000 and 400 cm^?1. Also certain spectra in the far infrared region 400-40 cm^?1 were obtained. Raman spectra of the crystalline solid, melt and as a saturated solution in acetonitrile were recorded and semiquantitative polarization measurements carried out. For N-D maleimide infrared and Raman spectra of the solid compound were recorded.The fundamental frequencies have been assigned in terms of C_2v, symmetry on the basis of infrared vapour contours and dichroism of the oriented film as well as on Raman polarization data. A force field was derived for maleimide, by initially transferring force constants from maleic anhydride and subsequent refinement of the force constants. The agreement between observed and calculated frequencies for the in-plane modes was satisfactory whereas certain large discrepancies remained for the out-of-plane vibrations.     

A comparison of two methods for the preparation of 3-Deazapurine ribonucleosides

The reaction of the trimethylsilyl derivative of 4,6-dichloroimidazo[4,5-c]pyridine with 2,3,5-tri-O-benzoyl- D -ribofuranosyl bromide gave four nucleosides-the α- and β-anomers of the 1-isomer and the α- and β-anomers of the 3-isomer (3.9:2.7:1.5:1). In contrast, the fusion reaction of 4,6-dichloroimidazo[4,5-c ]pyridine with 1,2,3,5-tetra-O-acetyl-β- D -ribofuranose gave a high yield of the 1-β-isomer, which was converted to the known 3-deazaadenosine (4-amino-l-β- D -ribofuranosylimidazo[4,5-c]pyridine).     

Interaction of a Cationic Polymeric Flocculant with Anionic Stabilizers in Latex

Turbidimetric titration of aqueous solutions of sodium dodecyl sulfate and Leukanol and coagulation titration of polystyrene and polybutadiene latexes containing various amounts of these surfactants are performed.