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.     

Über Enolderivate der Chlorophyllreihe. Darstellung von 132,173-Cyclophäophorbid-enolen. Vorläufige Mitteilung

Enol derivatives in the chlorophyll series. Preparation of 13²,17³-cyclopheophorbide enols 13²,17³-Cyclopheophorbide enols have been prepared as model systems for studying the effect of ring E enolization upon the properties of chlorophyll derivatives.     

Über die relative Reaktivität von Nucleophilen. Vorläufige Mitteilung

For a number of nucleophiles L an approximate linear correlation between the logarithms of the stability constants of methylmercury-complexes of L and the nuclear spin-spin-coupling constants J of Ch₃HgL was found.     

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.     

Über ein neues Verfahren zur Herstellung von. Acetylenverbindungen. Vorläufige Mitteilung

A new method for the preparation of acetylenes by reating α-halogeno- or α-sulfonyloxyketones with p-toluenesulfonylhydrazine is reported.     

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 .     

Zur Stereochemie der thermischen Fragmentierung von Hydrazonderivaten substituierter N-Amino-aziridine. Vorläufige Mitteilung

The thermally induced fragmentations of the hydrazones derived from phenylglyoxal and the diastereomeric 2,3-diphenyl-1-amino-aziridines and 2,3-dimethyl-1-amino-aziridines proceed with high stereospecificity.     

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.     

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.     

Zur Kenntnis der nickel-katalysierten Mischoligomerisation von Butadien mit Hydrazonen. Vorläufige Mitteilung

Studies on the nickel-catalysed reaction of butadiene with hydrazones The nickel-catalysed reaction of butadiene with methyl-hydrazones yields a series of isomeric azo-compounds identified as 2:1 adducts. The products are compared with those of the analogous reaction of butadiene with imines (cf. Scheme 1–3).     

Endocyclische SN-Reaktionen am gesättigten Kohlenstoff? Vorläufige Mitteilung

Fig. 1 illustrates a definition of the terms endocyclic and exocyclic SN-reactions, referring to intramolecular nucleophilic substitution processes that occur by an SN₂-analogous mechanism. Crossing experiments show that the methyl transfer I → II (see scheme 1) does not follow the formally appealing mechanism of the endocyclic SN-process III; the reaction proceeds intermolecularly under all conditions investigated. Kinetic measurements indicate that the methyl transfer XI → XII (see scheme 3) occurs in a similar fashion. This behaviour is believed to follow from the preference of tetrahedral carbon for backside attack by the nucleophile in SN₂-reactions. The general experience, according to which intramolecular reaction paths over cyclic transition states with ring sizes of 5 or 6 are preferred to their intermolecular counterparts, is not to be extrapolated to SN₂-reactions at tetrahedral carbon.     

Weitere Untersuchungen über den Mechanismus der reduktiven Spaltung von Azoverbindungen

The experimental results of our earlier investigation of the azodye bleach mechanism are interpreted in a revised manner. The reductive cleavage of methylorange by a dihydroquinoxaline proceeds in two steps. In the medium pH-range the first step (production of the hydrazo derivative) is slower (and not faster, as considered before) than the second (reductive splitting of the hydrazo derivative). In strongly acid solution this relation is reversed. The rate of disproportionation of the hydrazo derivative of methylorange is proportional to the concentration of the protonated hydrazo compound. For this reaction a two step mechanism is proposed in which a molecule of hydrazo compound is cleaved in a rate determining first step to an oxidizing particle and an amine molecule. In the following fast reaction the oxidizing intermediate attacks a second hydrazo molecule yielding methylorange and a further amine molecule. Based on this reaction sequence an azodye bleach mechanism is formulated which is able to explain the kinetics of the reductive cleavage of methylorange by a 1, 4-dihydroquinoxaline at any pH value. The azodye bleach mechanism is much more complex if the 1,4-dihydroquinoxaline used is able to form a radical or to tautomerize. The resulting reaction kinetics are discussed.     

Identifizierung von sechs Komponenten des Spurpheromons der Ameisenart Lasius fuliginosus. Vorläufige Mitteilung

Hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, and dodecanoic acid are components of the trail pheromone of the ant species Lasius fuliginosus. The acids were extracted from the contents of the rectal ampullae and identified by the mass spectra and gas chromatographic retention times of the corresponding methyl esters.     

Über Diels-Alder-Reaktionen des C60-Fullerens Vorläufige Mitteilung

On Diels-Alder Reactions of the C₆₀-Fullerene We report on the regioselective [4+2] cycloaddition of Buckminsterfullerene C₆₀( 1 ) at room temperature with 2,3-dimethylbuta-1,3-diene and with the monoterpene 7-methyl-3-methylideneocta-1,6-diene (= myrcene) and on the spectroscopic characterization of the corresponding crystalling monoadducts 2 and 3 . According to these experiments, 1 acts as a reactive dienophile, which can be functionalized regioselectively under mild and controlled conditons.     

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 .     

Reaktion von 3-Amino-2H-azirinen mit Diphenylcyclopropenthion. Vorläufige Mitteilung

Reaction of 3-Amino-2H-azirines with Diphenylcyclopropenethione 3-Dimethylamino-2H-azirines ( 4a , 4b ) react with diphenylcyclopropenethione ( 8 ) to give 4(3 H)-pyridinethione derivatives of type 10 (Scheme 3). The reaction mechanism for the formation of 10 is given in Scheme 3 by analogy with a previous reported one [4] [5]. Hydrolysis of the 4(3 H)-pyridinethione 10a yields 2-oxo-2, 3-dihydro-4(1 H)-pyridinethione ( 11 ) and reduction of 10a with sodium borohydride leads to the 2, 3-dihydro-4 (1 H)-pyridinethione 12 (Scheme 4). The results of the reaction of 4a , 4b and the thione 8 demonstrate the similarity to the reaction of 4a , 4b and 2 [5] (cf. Scheme 1). In contrast, the reactions of imines of type 7a with 2 and 8 , respectively, lead to different products (cf. [1] [6]).     

Die Photoelektron-Spektren von Chlor-, Brom- und Jodcyan. Vorläufige Mitteilung

The four bands which have been observed in the photoelectron-spectra of the cyanogen halides CICN, BrCN and ICN (region from 10 to 20 eV) have been assigned to the following states: .     

Enantioselektive Synthese von α-Phosphinoketonen. Vorläufige Mitteilung

Enantioselective Synthesis of α-Phosphinoketones The first asymmetric (C? P)-connective synthesis of α-phosphinoketones in high enantiomeric purity (e.e.91–97%) is described. Key step is the highly diastereoselective phosphinylation of SAMP-hydrazones (S)- 2 to produce α-phosphinohydrazones (S,R)- 3 , isolated as the more stable borane adducts. Subsequent ozonolysis afforded the title compounds (R)- 4 , potential ligands for enantioselective homogeneous catalysis.