Synthese makrocyclischer Lactone durch Ringerweiterung. Vorläufige Mitteilung

Synthesis of Macrocyclic Lactones by Ring Enlargement Reaction Treatment of 3-(1-nitro-2-oxocyclohexyl)propanal ( 1 ) prepared by Michael addition of 2-nitrocyclohexanon and acrylaldehyde with methyltri (2-propoxy)tita-nium yielded a mixture of 2 and 3 which was converted into 6-nitro-9-decanolide ( 4 ).     

Synthese makrocyclischer Lactame aus Ketonen durch Ringerweiterung. Vorläufige Mitteilung

Synthesis of Macrocyclic Lactams from Ketones by Ring Enlargement Reaction 2-Nitroalkanon 1 was converted to the N-substituted amide 3 by condensation with acrylaldehyde followed by reductive amination. Under the analogous reaction conditions, 2-nitrocyclododecanon ( 4 ) led to 12-nitro-15-pentadecanlactam ( 6 ).     

Additionsreaktionen von 2-Amino-1-azetinen mit Cyclopropenonen; Bildung von Azepinderivaten durch Ringerweiterung. Vorläufige Mitteilung

Addition Reactions of 2-Amino-1-azetines with Cyclopropenones; Formation of Azepine Derivatives by Ring Expansion Reactions The reaction of 2-amino-1-azetines of type 6 with 2,3-diphenylcyclopropenone ( 1a ) in acetonitrile leads to azetol[1,2-α]pyrroles (cf. 7 and 9 , Schemes 3 and 4) in good yield. It is remarkable that in the reaction of 6a with 1a only endo- 7 is formed. With silicagel in ether endo- 7 isomerizes to the thermodynamically more stable exo- 7 (Schemes 3 and 6). The crystal structure of the latter compound has been established by X-ray crystallography. The reaction of 6a and 2-isopropyl-3-phenyl-cyclopropenone ( 1b ) yields only one product, which isomerizes with silicagel in ether to exo- 10 (Scheme 4). The structure of exo- 10 has been determined by NMR-spectroscopy. It seems reasonable that this structure results from a nucleophilic attack of the four-membered amidine to the phenyl-substituted C-atom of 1b.     

Nickel-katalysierte Isomerisierung von Butadien-Hydrazon-Misch-Oligomeren. Vorläufige Mitteilung

Nickel-catalysed Isomerization of Unsaturated Azocompounds Unsaturated azocompounds, produced by the nickel-catalysed reaction of butadiene with hydrazones, can be isomerized in presence of the same nickel catalyst. The influence of nickel concentration, temperature and structure of the azocompound on this rearrangement is described.     

Photoelektron-Spektren von Cycloalkenen und Cycloalkadienen. Vorläufige Mitteilung

The photoelectron spectra of cis-cycloalkenes (with three to ten carbon atoms in the ring), of three isomeric, non-conjugated cyclodecadienes, and of cis, cis, -1, 3-cycloalkadienes (with five to eight carbon atoms in the ring) have been recorded. The essential features of their π-bands and of the first σ-bands are briefly discussed.     

Photochemisches Verhalten von 3,4-Diarylsydonen. Vorläufige Mitteilung

3, 4-Diphenyl-sydnone ( 1a ) and 3-p-tolyl-4-phenyl-sydnone ( 1b ) on irradiation with a mercury high-pressure lamp in pyrex vessels yield 2,4,5-triphenyl- ( 3a ) and 2-p-tolyl-4,5-diphenyl-1,2,3-triazole ( 3b ), respectively. Irradiation of 1a and 1b in the presence of dimethyl acetylene-dicarboxylate or indene leads to the formation of the pyrazoles 4a and 4b and the Δ²-pyrazolines 5a and 5b , respectively. Reactive intermediates of the photoreaction of 1a and 1b seem to be the diazirines 2a and 2b , which open to give the 1,3-dipolar structures 8a and 8b .     

Synthese yon 2,6-Diencarbonsäuren Vorläufige Mitteilung

Through sequential Claisen- and Cope rearrangements the chainlengthening of allylic alcohols by one isoprene unit was achieved. Treatment of (E)-1a first with lithium N-cyclohexyl-N-isopropylamide at ?70°, followed by trimethylsilylchloride and warming up to room temperature yielded after work-up 3a (R = H), which rearranged at 156° in high yield to (E/Z)-4a. An analogous reaction sequence transformed 6 to 8. Choosing lithium N-methylanilide as a base (E/Z)-9 was selectively rearranged to 12, which was converted to the Cecropia juvenile hormone precursor (E/Z)-4b.     

1, 6-Addition von Chlorsulfonylisocyanat. Vorläufige Mitteilung

A 1, 6-addition of sulfonyl chloride isocyanate to 5, 7-dimethyl-8-methylidene-tricyclo[3.2.1.0^2,7]oct-3-en-6-one ( 1 ) produced the new tricyclic skeleton of 4a, 6-dimethyl-2, 5-dioxo-2, 3, 4a, 5, 6, 8a-hexahydro-1H-6, 4-methenoquinoline-1-sulfonyl chloride ( 2 ). The structure of the new aza-tricyclic species has been elucidated by X-ray analysis.     

Automerisierung von 1,3,5,5-Tetramethylcyclohexa-1,3-dien. Vorläufige Mitteilung

1,3,5,5-Tetramethylcyclohexa-1,3-diene, specifically deuterated in all positions except the gem.-dimethyl groups ( 11 ), was synthesized and found to undergo a rearrangement in the gas phase at 560°, which leads to a statistical distribution of the 6 hydrogen atoms to all 16 positions. This shows that the title compound ( 2 ) automerizes under these conditions and that the reaction proceeds via a series of ring openings (to 5 ) followed by degenerate [1,7]-H-shifts and rig closures (back to 2 ) rather than via [1,5]-CH₃-shifts. It is suggested that the previously studied rearrangement of 5,5-dimethylcyclohexa-1,3-diene ( 1 ) to 1,5-dimethylcyclohexa-1,3-diene ( 3 ) takes its course by the same reaction pathway.     

Stereochemie des Übergangszustandes aliphatischer CLAISEN-Umlagerungen. Vorläufige Mitteilung

The stereochemistry of the transition state in the CLAISEN rearrangement of crotyl propenyl ethers ( 2 ) has been established. By heating trans, cis-, cis, cis- and trans, trans-crotyl propenyl ether at 142,5°, erythro and threo 2, 3-dimethylpent-4-en-1-al ( 3 and 4 ) were obtained. From the ratio 3/4 it was shown that the rearrangement of the three ethers largely involves (97–98%) a chair-like transition state.     

Über die Konstitution von Loroglossin. Vorläufige Mitteilung

The Constitution of Loroglossine. Loroglossine, a characteristic constituent of orchids, is shown to be bis-[4-(β-D -glucopyranosyloxy)-benzyl]-(2 R, 3 S)-2-isobutyl-tartrate ( 1 ). Hydrolysis and esterification gave 1 mol-equiv. of dimethyl (+)-2-isobutyl-erythro-tartrate ((+)-3) and 2 mol.-equiv. of a glucoside which, after acetylation, gave 4 , identical with a synthetic sample. The erythro configuration of (+)- 3 by oxidation of isobutyl-maleic acid with osmium tetroxide and subsequent esterification. The absolute configuration of (+)- 3 was based on Horeau experiments and NMR. data of the diastereomeric mixture of its esters 7 and 8 with S (+)- and R (?)-α-phenylbutyric acid respectively.     

Ein symmetrisches Tetrasulfolenoporphyrin als Reaktivbaustein,Vorläufige Mitteilung

A Symmetrical Tetrasulfolenoporphyrin as Reactive Building Block The efficient preparation of the symmetric tetrasulfolenoporphyrin 1 is reported, which shows good solubility in a variety of solvents. In 1 , four sulfone groups that symmetrically bridge the eight methylene groups in β‐position at the pyrrole rings provide four sulfolene (=2,5‐dihydrothiophene 1,1‐dioxide) units which are prone to cleavage by thermally induced extrusion of sulfur dioxide. The tetrasulfolenoporphyrin, accordingly, is indicated to lend itself to specific and multiple refunctionalization by the replacement of the sulfone groups by other functionalities in SO₂ extrusion/cycloaddition sequences. The predicted reactivity and the potential of a zinc complex of the tetrasulfolenoporphyrin as a reactive porphyrin module (see 5 b ) is tested in exploratory experiments. To this end, thermolysis of the tetrasulfolenoporphyrinatozinc 5 b in dichlorobenzene solution (at 140°) and in the presence of [5,6]fullerene‐C₆₀‐I_h gives the (fullereno‐porphyrinato)zinc 6 still having three sulfolene units and a `diagonal' (difullerenoporphyrinato)zinc 7 that still has two sulfolene units, in 14 and in 43% yield, respectively.     

Über die Synthese des Muscaflavins. Vorläufige Mitteilung,

Synthesis of muscaflavin A biomimetic type synthesis of the yellow dihydroazepine amino acid 5 isolated from fly agaric is achieved starting with carboxypyridyl alanine derivatives.     

Eine neue Methode zur Herstellung gemischter Disulfide. Vorläufige Mitteilung

A New Synthesis of Unsymmetrical Disulfides. A new synthesis of unsymmetrical disulfides 3a via alkylthio-dialkyl-sulfonium salts 6 is reported.     

1,1-Dimethyl-1-silacyclohexa-2,4-dien-tricarbonyleisen Vorläufige Mitteilung

1,1-Dimethyl-2,3,4,5-tetraphenyl-1-silacyclohexa-2,4-diene is isomerized by iron pentacarbonyl to 1,1-dimethyl-2,3,4,5-tetraphenyl-1-silacyclohexa-2,5-diene. However, iron pentacarbonyl with 1,1-dimethyl-1-sila-cyclohexa-2,4-diene yields 1,1-dimethyl-1-silacyclohexa-2,4-diene-tricarbonyl-iron.     

Zur Photodimerisierung von 3-Phenyl-2H-azirinen. Vorläufige Mitteilung

Irradiation of 3-phenyl-2H-azirine ( 2 ) in benzene solution with a high-pressure mercury lamp yields 4,5-diphenyl-1,3-diazabicyclo[3,1,0]hex-3-ene ( 4 ) and not 3-phenylimino-4-phenyl-1-azabicyclo[2,1,0]pentane ( 1 ), as had been reported previously by others [2]. 2-Methyl-3-phenyl-2H-azirine ( 3 ) yields on irradiation a 2:1 mixture of 2-exo, 6-exo- and 2-exdo, 6-exo-dimethyl-4,5-diphenyl-1,3-diazabicyclo[3,1,0]hex-3-ene (2-exo,6-exo- and 2-endo, 6-exo- 5 ). Irradiation of 2,3-diphenyl-2H-azirine ( 8 ) leads to the formation of 2,4,5-triphenyl-imidazole ( 9 ) and tetra-phenylpyrazine ( 10 ). The suggested reaction path for the generation of 9 and 10 is shown in Scheme 2.     

Synthese von 2,7-Dioxa-isotwistan und 2,7-Dioxatwistan. Vorläufige Mitteilung

The syntheses of 2,7-dioxa-isotwistane ( 14 ), 2,7-dioxa-twistane ( 19 ), and some of their derivatives ( 6 – 13 and 15 – 18 ) are described. The twistane-skeleton was obtained by a molecular rearrangement starting from the iodo-iso-twistane compound 8 .     

Photochemische Umwandlungen. XVIII Photochemische Isomerisierung annellierter Oxanorbornadiene Vorläufige Mitteilung

Photochemical cycloaddition reactions in anellated oxanorbornadiene derivatives have been investigated. In the case of 7a the tetracyclic isomer 8a can be isolated which adds dimethylacetylenedicarboxylate in the manner of a bis-homo-furan system. On thermal activation 8a yields the thiepino-oxepin derivative 9a. In contrast, on direct photoexcitation of the benzoxanorbornadiene the primary photoproduct cannot be identified, the reaction leading directly to the benz[d]oxepin.