Photolyse von indazolen,benzisoxazolen und anthranilen in saurer Lösung Vorläufige Mitteilung

Indazoles and anthranils on irradiation with a mercury high-pressure lamp in acidic solution (H₂SO₄/H₂O or H₂SO₄/CH₃OH) yield 2-amino-5-hydroxy(or methoxy)-benzaldehydes (acetophenones, respectively) as major products and 2-amino-3-hydroxy (or methoxy)-benzaldehydes (acetophenones, respectively) as minor products. Photolysis of benzisoxazoles in conc. sulfuric acid results in the formation of 2,5-and 2, 3-dihydroxybenzaldehydes (acetophenones, respectively). 5-Methylindazoles form on irradiation in diluted sulfuric acid 2-amino-5-methyl-benzaldehydes.     

Massenspektrometrische Untersuchung von Amiden. VIII—Vinyloge α-Spaltung und Nachbargruppenbeteiligung bei der Fragmentierung von Piperididen α,β-ungesättigter Carbonsäuren

The electron-impact-induced fragmentation of piperidides from β-substituted α, β-unsaturated carboxylic acids proceeds preferentially via 4-membered cyclic transition states. The development of a 6-membered ring, which is typical for α,β-unsaturated esters, occurs only to a minor extent. The mechanism of the reaction is best rationalised by the assumption of a vinylogous α-cleavage and a simultaneous neighbouring group participation of the amide function     

Löslichkeitsprodukte von Metalloxiden und -hydroxiden. 11. Mitteilung [1]. Die Löslichkeit von α-GaO(OH) bei 60°C in perchlorsauren Lösungen konstanter Ionenstärke

The solubility equilibrium of α-GaO(OH) has been investigated at 60°C in solutions of perchloric acid having a constant ionic strength I = 3 m (Na, H)ClO₄. The hydrogen ion concentration of the equilibrated solutions was measured with a glass electrode and the concentration of the dissolved Ga^III was determined by chelometric titration. The experimental data can be explained by assuming the equilibrium .     

α-Chlor-nitrone II: Eine Methode zur Darstellung von γ-Lactonen aus Olefinen. Über synthetische Methoden, 6. (vorläufige) Mitteilung

The addition products obtained by the Ag⁺-induced reaction of α-chloro-aldonitrones with olefins (see preceding communication) can be utilized efficiently for making γ-lactones (see scheme 1).     

Der Mechanismus der Hydrolyse von Chlortriazinen in protischen Lösungsmitteln. II. Mitteilung Über nukleophile uromatische Substitutionen

The complex kinetics found for the hydrolysis of 1, 3, 5-trichloro-s-triazine in 9/91% (v) acetone/water at 10.0°C have been evaluated as a function of the hydroxyl ion and the acetate ion concentration using an analogue computer. The kinetics are consistent with a nonsteady state mechanism in which the primary intermediate anion is protonated giving a neutral species whose concentration goes through a maximum during the course of the reaction. This secondary intermediate forms the final product by deprotonation and release of a chloride ion. The product itself can undergo a second (reversible) deprotonation. In dimethylsulfoxide the analogous intermediate of the hydrolysis of 1, 3-dimethoxy-5-chloro-s-triazine can be identified by analysis of the NMR. and UV. spectra.     

Zum Mechanismus Massenspektrometrischer Fragmentierungsreaktionen. XVI—hydrid-Wanderungen bei der Fragmentierung von αω-Dimethoxyalkyl-Ionen

The isomerization and fragmentation of α,ω-dimethoxyalkyl ions a (CH₃OCH₂(CH₂)_n- CH⁺OCH₃, n = 1-6) has been investigated by deuterium labelling. It is shown that a isomerizes to ion a' by hydride transfer from the ω-CH₂ group to the positive charge at the α-C-atom before elimination of methanol. Both methoxy groups are lost as methanol. The amount of isomerization can be deduced from alkene elimination from [a ? CH₃OH]+ ions in deuterated derivatives of a. On average at 70 eV three rearrangement steps involving hydride transfer are observed.     

Thermische Lactonisierung von Estern γ-Brom-α, β-ungesättigter Carbonsäuren zu Δα-Butenoliden. Direkte γ-Bromierung von α, β-ungesättigten Säuren

By heating with iron powder at 120–150° some γ-bromo-α, β-unsaturated carboxylic methyl esters, and, less smothly, the corresponding acids, were lactonized to Δ^7alpha;-butenolides with elimination of methyl bromide. The following conversions have thus been made: methyl γ-bromocrotonate ( 1c ) and the corresponding acid ( 1d ) to Δ^α-butenolide ( 8a ), methyl γ-bromotiglate ( 3c ) and the corresponding acid ( 3d ) to α-methyl-Δ^α-butenolide ( 8b ), a mixture of methyl trans- and cis-γ-bromosenecioate ( 7c and 7e ) and a mixture of the corresponding acids ( 7d and 7f ) to β-methyl-Δ^α-butenolide ( 8c ). The procedure did not work with methyl trans-γ-bromo-Δ^α-pentenoate ( 5c ) nor with its acid ( 5d ). Most of the γ-bromo-α, β-unsaturated carboxylic esters ( 1c, 7c, 7e and 5c ) are available by direct N-bromosuccinimide bromination of the α, β-unsaturated esters 1a, 7a and 5a ; methyl γ-bromotiglate ( 3c ) is obtained from both methyl tiglate ( 3a ) and methyl angelate ( 4a ), but has to be separated from a structural isomer. The γ-bromo-α, β-unsaturated esters are shown by NMR. to have the indicated configurations which are independent of the configuration of the α, β-unsaturated esters used; the bromination always leads to the more stable configuration, usually the one with the bromine-carrying carbon anti to the carboxylic ester group; an exception is methyl γ-bromo-senecioate, for which the two isomers (cis, 7e , and trans, 7d ) have about the same stability. The N-bromosuccinimide bromination of the α,β-unsaturated carboxylic acids 1b , 3b , 4b , 5b and 7b is shown to give results entirely analogous to those with the corresponding esters. In this way γ-bromocrotonic acid ( 1 d ), γ-bromotiglic acid ( 3 d ), trans- and cis-γ-bromosenecioic acid ( 7d and 7f ) as well as trans-γ-bromo-Δ^α-pentenoic acid ( 5d ) have been prepared. Iron powder seems to catalyze the lactonization by facilitating both the elimination of methyl bromide (or, less smoothly, hydrogen bromide) and the rotation about the double bond. α-Methyl-Δ^α-butenolide ( 8b ) was converted to 1-benzyl-( 9a ), 1-cyclohexyl-( 9b ), and 1-(4′-picoly1)-3-methyl-Δ^α-pyrrolin-2-one ( 9 c ) by heating at 180° with benzylamine, cyclohexylamine, and 4-picolylamine. The butenolide 8b showed cytostatic and even cytocidal activity; in preliminary tests, no carcinogenicity was observed. Both 8b and 9c exhibited little toxicity.     

Zum Einfluß der Halogenmodifizierung auf das acide Verhalten von γ-Al2O3

Influence of Modification of γ-Alumina by Halides on the Acidic Behaviour The influence of modification of γ-alumina by Cl and F on the acidic properties was studied by means of i.r. spectroscopic methods using ammonia as probe molecule. The measurements show a significant rise in Lewis acidity.     

Photochemische Reaktionen. 116. Mitteilung [1]. Notiz zur 1γ, δ*-induzierten Photospaltung von γ, δ-Epoxy-eucarvon

π, π*-Induced Photocleavage of γ, δ-Epoxy-eucarvone . On ¹π, π*-excitation 1 undergoes cleavage of the C, C-oxirane bond ( 1 → c ) and isomerizes to the bicyclic dihydrofurane compound 5 . In addition, 1 shows photocleavage of the C (γ), O-oxirane bond ( 1 → d ) and gives the isomers 2, 3, 6, 7 and 8. Furthermore, the cyclohexenone 9 and the cyclohexene-1, 4-dione 10 are formed presumably via an intermediate 13 , which could also arise from d. Besides these products the compounds 11 and 12 are obtained, which are photoproducts of 2 .     

Die Hydrolyse von 6exo-substituierten 2exo- und 2endo-Norbornylestern der p-Toluolsulfonsäure. Norbornanreihe. 3. Mitteilung

The Hydrolysis of 6 exo -Substituted 2 exo - and 2 endo -Norbornyl p -Toluenesulfonates. Norbornane Series. Part 3 Hydrolysis of the 6exo-substituted 2exo- and 2endo-norbornyl p-toluenesulfonates 1b - 1 and 2b - 1 , respectively, in 70% dioxane led to different amounts of the following products: Unrearranged 2exo-norbornanols 3 and norbornenes 5 , accompanied in somes cases by small amounts of the rearranged Rendo-epimers 4 and 6 and by norticyclenes 7 . When the 6exo-substituent was a nucleophilic group as in 1e - 1 and 2e - 1 , various amounts of tricyclic products were also formed by endo-cyclization. These results show that the 2exo- and 2endo-esters 1 and 2 , respectively, react by way of different intermediates. In cases where the 6exo-substituent was an n-electron donor, as in 1m - r and 2m - r , quantitative fragmentation to (3-cyclopentenyl)acetaldehyde (13) occurred.     

Über die Hydrolyse von Eisen(III)Salzlösungen. I. Die Hydrolyse der Lösungen von Eisen(III)chlorid

When a very diluted iron(III)chloride solution is slowly alkalified by a weak base, the deprotonation of [Fe(H₂O)₆]³⁺ proceeds in a first stage to form mono- and dinuclear hydroxoaquo-complexes. In a second stage 4 dimers condense around a chloride ion to form an eight membered ring, an embryon, which grows fast to very small crystals of the composition Fe₄O₃(OH)₅Cl and the structure of the β-FeOOH. These crystalline micells remain colloidally dissolved. If the pH is raised above approximately 3.4 the Cl^?- are exchanged against OH^?-ions and flocculation occurs. This shows that Pauli, assuming the micells of such sols to be polynuclear complex ions, is basically correct, and it follows that micells can also be micro-crystals. When an iron(III)chloride solution is neutralized fast with a strong base, an ‘amorphous’ precipitation is obtained which gives with MoK_α-X-rays only two broad reflections, showing that the iron oxide hydroxide octahedra are condensed in a highly disordered way. The coherently scattering areas of this precipitate are probably tetramers. Small amounts of primarily formed amorphous iron(III)hydroxide are transformed into β-FeOOH.