A Contribution to the Micro Determination of Active Hydrogen in Organic Compounds by Lithium Aluminium Hydride*

After the discovery of lithium aluminium hydride and its remarkable reducing properties it was soon evident that the reactions of LiAlH4 are similar in many respects to those of Grignard reagents. That the more aggressive behaviour of the hydride may be useful for an analytical procedure was shown several years ago by replacement of the Grignard reagent in the Zerewitinoff procedures for the determination of active hydrogen

A Simple Assembly for Carbon Determination in Water

The classical assembly for carbon and hydrogen analysis in organic compounds was modified for the determination of carbon in water samples. Numerous analyses of known solutions and of waste and surface waters containing 5 mg-10 g carbon/I were performed. The accuracy and reproducibility of results were satisfactory. The range of applicability is limited by the sensitivity of the gravimetric determination: on one side and on the other by the sample volume accessible

Determination of Methoxyl and Ethoxyl Groups in Organic Compounds

Determination of methoxyl and ethoxyl groups in organic compounds according to Zeisel \u27s method frequently yielded somewhat higher analytical values. This usually occured when the methyl or ethyl iodide was insufficiently purified from matters which hindered their determination. Liquid-filled washers are used for the elimination of these matters. When the liquids in the washer were replaced by solid ascarite, and the determination carried under a stream of nitrogen or air, no errors occurred . Besides, if a layer of anhydrone was added to the washer containing ascarite, the carbon and hydrogen content of the obtained methyl or ethyl iodide could be determined, and it could thus be ascertained whether the organic compound contained methoxyl groups, ethoxyl groups, or a mixture of both

A Simple Assembly for Carbon Determination in Water

The classical assembly for carbon and hydrogen analysis in organic compounds was modified for the determination of carbon in water samples. Numerous analyses of known solutions and of waste and surface waters containing 5 mg-10 g carbon/I were performed. The accuracy and reproducibility of results were satisfactory. The range of applicability is limited by the sensitivity of the gravimetric determination: on one side and on the other by the sample volume accessible

Studies in the Muscarine Series. VI. Muscarinic Activity of Some 1,3-Dioxolanes and 1,3-Dithiolanes

The synthesis of 1,3-dioxolanes Va-e and Vla-b, and the dithiolane III is described. A discussion is given of the structural relationship between these compounds and nratural muscacrine; their muscarinic activity was determined

Further Characterization and Isolation Studies in the Muscarine Series*

A description is given of the separation of muscarine from choline using ion exchange chromatography on Dowex 50X8 resin. Muscarine tetraphenylboron is also described ; the interpretation of the infrared spectrum of this compound is given

Optically Active Trisulphides and Tetrasulphides Related to L-Cystine

A . description is ,given of the preparation and properties of optically active bis(2-carboxy - 2- phthalimidoethyl) disulphide (Ia), [a]D-275°, bis(2-carboxy -2.:phthalimidoethyl) trisulphide (lb) , ,[a]D -4720 and bis(2-c arboxy -2-phthalimidoethyl) tetrasulphide (le), [a]D:--3880. The starting material for these compounds was N - -phthaloyl-L-cysteine (II), [a]D-64° prepared from L-cysteine hydrocl).loride and sodium o- carbethoxythiobenzoa te

Structure Determination of Isomeric Pyronopyrones Synthetized from 2,4-Dioxo-4-(4-hydroxy-6-methyl-2-pyrone-3-yl) Butyric Acid Ethyl Ester

Two isomeric pyronopyrones were obtained by cyclization of 2,4-dioxo-4-(4-hydroxy-6-methyl-2-pyrone-3-yl) butyric add ethyl ester in glacial acetic acid or acetic anhydride. The structures of the compounds are discussed on the basis of their infrared, ultraviolet, 1H NMR, 13C NMR and mass \u27Spectra as well as chemical properties observed

Studies in the Muscarine Series. VI. Muscarinic Activity of Some 1,3-Dioxolanes and 1,3-Dithiolanes

The synthesis of 1,3-dioxolanes Va-e and Vla-b, and the dithiolane III is described. A discussion is given of the structural relationship between these compounds and nratural muscacrine; their muscarinic activity was determined

Reaction Products of 2, 7-Diaroyl-4,5-Fulvenotropones with Hydrazine Hydrate

6\u27 -Hydroxy-8~( a-hydrazonoarylmethyl)ful veno(2\u27 ,3\u27 -5,6)-1,2-diazaazulenes (IIIa, Ar==tolyl; IIIb, Ar==phenyl; IIIc, Ar==thienyl) were obtained as reaction products of corresponding 2,7-diaroyl-4,5-fulvenotropones with hydrazine hydrate. The structure of the obtained compounds are discussed on the basis of their infrared, mass and 1H nuclear magnetic resonance spectra