Die Massenspektren weiterer Verbindungen aus der Pyrolyse von Methylchlorsilanen

Zusammenfassung Die Massenspektren vom Si-Hexamethyldisilylmethylen und Si-Hexamethylcyclocarbosilan sowie ihrer hydrierten Produkte werden diskutiert. Die charakteristischen Bruchstückionen (P-15) und (P-1) gestatten die eindeutige Zuordnung der Molekulargewichte.

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Summary The mass spectra of the linear silicon-methylene compound [(CH₃)₃Si]₂CH₂ and of the cyclic compound Si₃(CH₂)₃(CH₃)₆ (6-ring) as well as their hydrogenated products up to (H₃Si)₂CH₂ and Si₃(CH₂)₃H₆ are given and discussed. The characteristic fragments ion (p-15) and (p-1) allow the unequivocal coordination to the molecular weights of the components.

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Der Deutschen Forschungsgemeinschaft und dem Land Nordrhein-Westfalen danken wir für die Förderung unserer Untersuchungen.     

Die Massenspektren der Nikotin-N-Oxide und der mit Ihnen Verwandten Tetrahydrooxazine

The mass spectra of the three nicotine-N-oxides are discussed, together with the spectra of tetrahydrooxazines. The compounds with an N-oxide function in the five membered ring partly rearrange thermally before electron-impact fragmentation.     

Über die Synthese von Verbindungen mit dem Skelett der Homoproaporphine. 7. Mitteilung über natürliche und synthetische Isochinolinderivate

The synthesis of the tetracyclic spiro compounds 11, 12, 13, 14, 17, 18, 19 and 20 with homoproaporphine skeleton is described. Crucial intermediates are the secondary alcohols 10 and 16 . The structure of the spiro compounds is proved by transformation of 11 into the dihydronaphthalene derivative 24 and NMR.-spectroscopic studies of the latter.     

Über die Cyanamidolyse von Natriumtri- und -tetrametaphosphat

Cyanamidolysis Reactions of Sodium Tri- and Tetrametaphosphate Reactions of Na₂NCN with sodium tri- and tetrametaphosphate are leading to the formation of Na₃PO₃N₂C, NaPO₂(N₂(C)₂), Na₃PO₄, and Na₄P₂O₇, respectively. In alkaline aqueous solutions hydrolysis and cyanamidolysis reactions occur parallel. The course of the different reactions is discussed.     

Über den Einfluss der pK-Werte von Anilinen auf die Bildung und Folgereaktionen von substituierten Butadienen aus Cumalinsäure-methylester

The Influence of Aniline pK Values on the Formation and Reactivity of Substituted Butadienes from Methyl Coumalate The product of the reaction between 2 equiv. of methyl coumalate ( 1 ) and 1 equiv. of a substituted aromatic amine depends on the pK value of the latter. Aromatic amines with pK values between 1.05 and 2.8 produce bicyclic lactones 4 , whereas those with higher pK values also give 2-azabicyclo[3.3.1]nona-3,7-diene-9-carboxylic acids 9 . The latter, products of the intramolecular Diels-Alder reaction 8 → 9 , may in certain cases even prevail.     

Über die Cycloaddition von Dithiocyan und Trithiocyan mit Hexafluoraceton und Folgeprodukte aus der Spaltung der Schwefel-Schwefel-Bindung mit elementarem Chlor im Dithiocyan-Hexafluoraceton-Addukt

Cycloaddition of Dithiocyanogen and Trithiocyanogen with Hexafluoroacetone and Products of the Cleavage of the Sulfur-Sulfur Bond in Dithiocyan-Hexafluoroacetone Adduct by Elemental Chlorine The reaction of dithiocyanogen and trithiocyanogen with hexafluoroacetone (HFA) leads to the cycloaddition products (SCN)₂ · 4 HFA 1 and S(SCN)₂ · 4 HFA 2 . These are the first reactions of (SCN)₂ and S(SCN)₂ without cleavage of the S—S bonds. Elemental chlorine cleaves in 1 the S? S bond and 3 is formed. In 3 the chlorine atom can be replaced by the rests —CN 4 , (C₆H₁₁)₂N— 5 , and n-C₄H₉– 6. 6 eliminates one molecule of HFA by warming up and the four-membered ring 7 is formed. The compounds were characterized on the basis of mass and nmr spectra.     

Über Chalkogenolate. 86. Massenspektren von Dialkyltrithiocarbonaten

On Chalcogenolates. 86. Mass Spectra of Dialkyl Trithiocarbonates Dialkyl trithiocarbonates have been studied by means of mass spectra. The decomposition schemes are communicated.     

Über die Verdampfungsthermodynamik und die Bildungsenthalpien von CaSe,SrSe und BaSe

On the Thermodynamics of Vaporization and the Enthalpies of Formation of CaSe, SrSe and BaSe The congruent vaporization of the solid compounds CaSe, SrSe and BaSe of stoichiometric composition was studied over the temperature ranges 1832?2138 K, 1862?2122 K and 1860?2158 K, respectively, by the Knudsen effusion weight-loss method. Using enthalpy and entropy data from the literature for gaseous M, MSe, Se₂ and Se (M = Ca, Sr, Ba) and estimated data for the standard entropies and enthalpy functions of solid MSe, it can be shown that within the given temperature ranges CaSe and SrSe vaporize predominatly to the atomic species, while in case of BaSe the mode of vaporization to the atoms and to the molecular species BaSe are of about equal importance. The Se₂-content of the gas phase is very small in all cases. The following second and third law enthalpies and entropies (indices II and III respectively) were derived for the vaporization to the gaseous elements: see “Inhaltsübersicht”. The following standard enthalpies of formation of MSe(s) were derived from the third law enthalpies (in kJ · mol^?1): CaSe: ?445 ± 44; SrSe: ?451 ± 42; BaSe: ?467 ± 44.     

Massenspektren Alicyclischer Verbindungen. IV—Die Massenspektren der Thiacycloalkanone und der Thiacycloalkanon-1,1-Dioxide

The electron-impact-induced fragmentation of some 1-thiacycloalkanones and their 1, 1-dioxides of ring size 5 to 8 was studied. The results were compared with the fragmentation pattern of the cycloalkanones, the thiacycloalkanes and the 1-thiacycloalkan-1, 1-dioxides. It was found that in thiacycloalkanones the charge localisation predominates at the sulphur.     

Über die «aus dem Ring»-Claisen-Umlagerung von Naphthalinderivaten

When a mixture of (E)- and (Z)-1-propenylnaphth-2-yl-allylether ((E/Z)- 5 ) is heated to 182° only the (E)-isomer rearranges to give the ‘out-of-ring’ product (E/Z)- 16 , (Z)- 5 remains unchanged. At higher temperature (Z)- 5 yields 2-methyl-naphtho[2,1-b]furane ( 15 ) as the main product. The mixture of β-chloro-allyl derivatives (E/Z)- 6 behaves in a similar way. These findings led us to suspect that the ‘out-of-ring’ products 16 and 18 are formed by direct [1, 5s] allyl migration from the starting ethers (E)- 5 and (E)- 6 . Kinetic' measurements made on (E)- and (Z)- 5 and the independently synthesized (E)- and (Z)-1-allyl-1-propenyl-1 H-naphthalen-2-ones ((E)- and (Z)- 17 ) show however, that the ethers (E)- 5 and (E)- 6 undergo a double [3s, 3s] rearrangement (i.e. Claisen followed by Cope rearrangement) and hydrogen migration to yield the ‘out-of-ring’ products (E/Z)- 16 and (E/Z)- 18 (Scheme 9). In the (Z)-series steric factors prevent the intermediate naphthalenones (Z)- 17 and (Z)-19 from undergoing the Cope rearrangement and instead, at higher temperature, cleavage of the allyl group occurs (Scheme 11). The isopropenyl derivative 7 behaves in a similar way (Scheme 5). Rearrangement of (E/Z)-1-propenylnaphth-2-yl benzyl ether ( 8 ) requires a higher temperature (214°). The nature of the products obtained (Scheme 4) makes the occurrence of a direct sigmatropic [1,5s] shift of the benzyl group very unprobable. In the case of (E/Z)-2-propenylnaphth-1-yl allyl ether ( 10 ) both isomers rearrange to yield the ‘out-of-ring’ product 30 and the para-Claisen product 32 (Scheme 7). This experiment also provides evidence against a sigmatropic [1,5s] shift of the allyl group. The same conclusion can be drawn from the thermal behaviour of (E/Z)-2-propenylphenyl allyl ether (11) and 6-t-butyl-2-propenylphenyl allyl ether ( 12 ) where only 11 yields traces of the ‘out-of-ring’ product 35 (Scheme 8). Up to this date there is no evidence whatsoever for the existence of a sigmatropic [1,5s] migration of an allyl group from oxygen to carbon. Thermal rearrangement of (E/Z)-1-propenylnaphth-2-yl propargyl ether ( 9 ) yields only (E/Z)-1-propenyl-benz[e]indan-2-one ( 27 ) (and its secondary product 28 ). The mechanism for this reaction is given in Scheme 12. Treatment of a mixture of (E/Z)- 18 with base yields the (Z)-cyclisation product 2,4-dimethylnaphth[2,1-b]oxepine ( 43 ) (Scheme 13).     

Über die Deammonisierung und Dehydroxylierung von NH4-Chabasit

Deammoniation and Dehydrosylation of NH₄-Chabazite The deammoniation of NH₄-chabazite is completely reversible. Compared to other investigated zeolites the hydrogen form of chabazite remains stable at higher temperatures and over a wider temperature range. Thermoanalytic and by IR spectrophotometry two types of OH groups with OH-stretching bands at 3565 and 3615 cm^?1 can be distinguished. Water saturation of H-chabazite at room temperature results in irreversible changes of the crystal structure. The thermostability of the deriving lattice is extremely low and no acidic OH groups are detectable any more. It is supposed that in the completely hydrated H-chabazite acidic H₃O⁺ ions solved out aluminium from the lattice which occupies some of the cationic lattice sites. The dehydroxylation is an irreversible process and is accompanied by a lattice collapse.     

Über die Massenspektroskopische Untersuchung von Diimin und seinen Deuterierungsprodukten

Mass Spectroscopic Investigation of Diimide and its Deutero Products The formation of mono and dideuterodiimide was investigated by spectroscopic means. By high resolution techniques the deuterated products could be identified and their mode of formation ascertained from the isotope-distribution. The stabilities of the molecular and fragment ions were estimated from ionization and appearance potentials. Appearance potentials (electron-impactionizations) were estimated. The field ionization spectra indicate the thermally induced disproportionation of the formed diimide. By measuring the metastable transitions according to the DADI method a fragmentation scheme for diimide can be specified.