Strukturen und reaktionen von methylantimondihalogeniden und versuche zur darstellung von methylantimon

MeSbCl₂ (1) and SbCl₃ give the adduct MeSbCl₂·0.6SbCl₃ (1a). MeSbBr₂ (2) reacts with NaI to form MeSbI₂ (3) and with Cr(CO)₅ THF to give Me(Br)₂SbCr(CO)₅ (4). The crystal structures of 1a, 2 and 4 are reported. Derivatives of methyl antimony are obtained by reaction of 2 or 4 with Mg in tetrahydrofuran.     

Versuche zur Synthese von [2.2]- und [2.3]Cyclopentadienophanen

Synthetic Attempts towards [2.2]- and [2.3]Cyclopentadienophanes . The first [2.2]Cyclopentadienophane (=2,2,3,3,8,8,9,9-octamethyltricyclo[8.2.1.1^4,7]tetradecatetraene; 1b ) has been synthesized (Scheme 5) by reductive coupling of 6,6-dimethylfulvene 3 → 5 (50%) followed by base-induced twofold condensation of 1,2-di(cyclopentadienyl)-1,2-dimethylbutane 5 with acetone to give difulvene 15 (95%). Reductive coupling of 15 gives a complex mixture of tautomers of 16 , 17 , and 1b , which contains ca. 50% of the target molecule 1b . Other synthetic attempts towards [2.2]cyclopentadienophanes 1a and 1b and [2.3]cyclopentadienophane 18 are discussed.     

Eine sehr einfache Reaktion zur Erkennung von Vanillin und Lignin geben

Ohne Zusammenfassung     

Das zur Bestimmung von Wolfram [1]

Ohne Zusammenfassung     

Synthese und Struktur von Vinamidinatodiiodalanen [1]

The diiodoalanes (C₅H₇R₂N₂)AlI₂ [ 6 ; R = Me ( a ), Ph ( c )] are obtained from the corresponding alanes (C₅H₇R₂N₂)AlH₂ ( 5 ) and [Me₃NH]I in good yields. (C₅H₇R₂N₂)AlI₂ [ 6 ; R = iso‐Pr ( b )] is alternatively prepared, as well as 6a , from the corresponding vinamidine lithium compound C₅H₇R₂NLi ( 8 ) and AlI₃. (C₅H₇Me₂N₂)AlBr₂ ( 9a ) is formed according to both methods. The X‐ray structures of 6a and 6b are reported.     

4-Phenylthiosemicarbazid als Reagens zur Charakterisierung von Aldehyden und Ketonen

Ohne ZusammenfassungMeinem verehrten Lehrer, Frau Prof. Dr. Ing. M.Perpar, sage ich auch an dieser Stelle für die erfahrene Hilfe herzlichen Dank.     

2,8,9-Trioxa-5-aza-1-sila-bicyclo[3.3.3]undecan-3-one,ein neuer typ von silatranen; darstellung und eigenschaften

A new type of silatranes (2,8,9-trioxa-5-aza-1-silabicyclo[3.3.3] undecan-3-ones) has been prepared by reaction of organotrimethoxysilanes with N-bis(2-hydroxyethyl)aminoacetic acid.The solvolytic stability compared with that of simple acyloxysilanes, the extremely decreased basicity of nitrogen and the NMR spectra prove the pentacoordination of silicon in these compounds. Basicity and NMR data are substituent-dependent.     

Die papierchromatographische Kristallisation als Methode zur Herstellung von Komplexverbindungen und zur Reinigung von seltenen Elementen, 1. Mitt.

Zusammenfassung Durch papierchromatographische Kristallisation ist es möglich, die Kristallisationsbedingungen für schwer kristallisierende Oxalatokomplexe des Al, Ga, In, Cr, Fe, Zr, Hf, Nb, Ta, Ti, Ge zu ermitteln und die kristallisationshemmenden Oxo- bzw. Hydroxokomplexformen quantitative zu eliminieren.Unter Ausnützung der verschieden großen Wanderungsgeschwindigkeit sowie dem unterschiedlichen Verhalten der Oxalate bzw. Oxalatokomplexe der Verunreinigungen und den dabei auftretenden Verteilungs-, Adsorptions-und Ionenaustauschvorgängen bei der papierchromatographischen Kristallisation kann diese zur Feinstreinigung einiger seltener Elemente wie z. B. Ge, Zr, Nb, Sc, U, In u. a. über Oxalate bzw. Oxalatokomplexe verwendet werden.Die Verteilung der Verunreinigungen während der papier-chromatographischen Kristallisation hat einen komplizierten Charakter und kann nicht durch Adsorption oder mechanische Einfügungen der Mutterlauge allein erklärt werden.

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Paper chromatographic crystallization, a method for the preparation of complex compounds and for the purification of rare elements, I.

With the help of the paper chromatographic crystallization technique it is possible to determine optimum crystallization conditions of the badly crystallizing oxalato complexes of Al, Ga, In, Cr, Fe, Zr, Hf, Nb, Ta, Ti and Ge and to remove quantitatively their crystallization inhibiting oxo and hydroxo complexes, resp. The different migration rates and the behavior of the oxalates and oxalato complexes of the impurities as well as the distribution, adsorption and ion exchange phenomena operative in paper-chromatographic crystallization may be used for ultra-purification of some rare elements by means of their oxalates and oxalato complexes, for instance for Ge, Zr, Nb, Sc, U, In, and others. The distribution of impurities in paper chromatographic crystallization follows a complicated mechanism and is not explainable on the basis of adsorption or mechanical interaction of mother liquors alone.

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Mit 2 Abbildungen     

Eine Methode zur Bestimmung sehr kleiner Mengen von Phenyl- und Methylquecksilbersalzen in biologischem Material

Ohne Zusammenfassung     

Zur acylierung von 5-aryl-tetrazolen; ein duplikationsverfahren zur darstellung von polyarylen

We have found that the thermolysis of 5-substituted-2-acyl-tetrazoles (I) at 60–110° leads to quantitative loss of nitrogen and formation of an N-acyl-nitrilimine (III) as a hypothetical intermediate. This immediately reacts via ring closure to form 1,3,4-oxadiazoles (IV) in excellent yields. By an elegant reaction series it is possible to form polyaryles with alternating phenyl and 1,3,4-oxadiazole rings by repeated reaction of 5-phenyltetrazole with p-cyano-benzoylchloride followed by treatment with lithium azide. Starting with terephthalonitrile polyaryles possessing 9 rings were synthesized in 4 steps. The ultra-violet absorption of the 2,5-disubstituted 1,3,4-oxadiazole systems resembles very closely the absorption curve of a p-disubstituted phenyl-group.     

Ein sehr empfindliches Verfahren zur Mikrobestimmung von Wasserstoffperoxid

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Eine verbesserte und sehr genaue Methode zur potentiometrischen Bestimmung von Plutonium bei konstantem Strom

Ohne Zusammenfassung     

Ein neues,einfaches verfahren zur darstellung von ammonium- und phosphonium- betainen der quadrätsaure

Squaric acid 1 reacts with equimolar amounts of tertiary amines 7 and tertiary phosphines 8 in acetic anhydride to afford the monocondensation-products 4 and 5 , respectively.     

Über organogermaniumtrisulfinsäureester und versuche zur darstellung von tetrasulfinsäureestern des germaniums

The trisulfinic esters of germanium RGe(O₂SR′)₃ (R = R′ = CH₃; R = C₆H₅, R′ = CH₃, C₂H₅), which are sensitive to hydrolysis and temperature, are obtained by reaction of the corresponding trichlorides RGeCl₃ with anhydrous silver sulfinates. Aromatic trisulfinic esters as well as tetrasulfinic esters of germanium could not be obtained because of steric reasons. The esters, in which the RSO₂^?-residues are linked to germanium via oxygen, are investigated on the basis of their ¹H NMR, mass, IR and Raman spectra.     

Bemerkung zur vorstehenden Notiz [1] von H. REMBOLD

The possible transition state conformations (chair (S), boat (W), and twist (T), respectively cross (K) forms) and methods for their determination in the thermal ortho-CLAISEN rearrangement of allyl aryl ethers are discussed. Crotyl 3,5-dimethylphenyl ether ( 11 ) gives a mixture of 2-(α-methylallyl)-3,5-dimethyl-phenol ( 12 ) and 4-crotyl-3,5-dimethyl-phenol ( 13 ) on heating in N, N-diethylaniline. Values of 3 and 31 were obtained for the ratio of 12 / 13 for trans- 11 and cis- 11 , respectively. It therefore follows that both ethers rearrange steroselectively ( > 90%) by the S or W forms of the activated complex. αMethylallyl 6-alkylphenyl ethers rearrange on heating in various solvents to a mixture of trans-and cis-2-crotyl-6-alkyl-phenols. The amount of the cis-phenols in the rearrangement products decreases with the increasing bulk of the 6-alkyl substituent. This result is only obvious if the chair form of the transition state during the rearrangement of these ethers is highly favoured. trans-Crotyl 2,6-dimethylphenyl ether (trans- 33 ) rearranges highly steroselectively (94%) on heating to trans-4-crotyl-2,6-dimethyl-phenol (trans- 34 ). In the case of the corresponding cis ether 33 , the rapid cis → trans isomerisation of this ether and the cis/trans ratio of the phenol 34 indicate that the reverse rearrangement of the intermediate ortho-dienone to the ether 33 and the further rearrangement to 4-crotyl-2,6-dimethyl-phenol ( 34 ) has little stereoselective character.