Über eine neue Ringschlussreaktion mit 3-Dimethylaminopropyl-carbinolen zu Oxolanen. Mitteilung über Grignard-Reaktionen mit Halogenalkylaminen [1]

A new ring-closure reaction is described, consisting in the treatment of basic carbinols of types 2 , 8 , 13 , 16 , with sodamide or sodium hydride, and adding to the sodium salts formed an alkyl halide. Oxolanes of types 5 , 9 , 14 , 17 , 20 , are formed.     

Chaenorhin,ein macrocyclisches Spermin-Alkaloid. 149. Mitteilung über Alkaloide

Structure 1 has been elucidated for chaenorhine, an alkaloid isolated from Chaenorhinum organifolium (Scrophulariaceae). The key derivative for the structural elucidation is 13,14,21,22-tetrahydro-21,22-seco-chaenorhine ( 21 ). 21 gave upon hydrolysis spermine and 4-hydroxydihydrocinnamic acid characterized as the tetraacetyl derivative 18 and as the dimethyl derivative respectively.     

Die Herzglykoside des Pfeilgiftes von Lophopetalum toxicum LOHER. 13. Mitteilung über Celastraceen-Inhaltsstoffe

The Heart Glycosides of the Arrow Poison of Lophopetalum toxicum LOHER From the cytotoxic and positive inotropic acting bark extract of the Philippinan Lophopetalum toxicum eight heart glycosides have been isolated and their structures have been elucidated mainly by field-desorption-MS- and ¹- and ¹³C-NMR spectroscopy. Besides the known k-Strophanthidin ( 1 ), Antiarigenin ( 6 ) and β-Antiarin (Antiarigenin-3-β-O-α-L -rhamnoside, 10 ) the following mono- and diglycosides could be identified: strophanthidin-3-β-O-α-6-desoxy-D -allopyranoside (strophalloside, 2 ), strophanthidin-3-β-O-β-6-desoxy-D -glucopyranoside (= Strophanthidin chinovoside, 3 ), strophanthidin-3-β-O[-4Oβ-D -allopyranosyl-β-6-desoxy-D -allopyranoside] ( 4 ), strophanthidin-3-β-O-[3-O-β-D -glucopyranosyl-β-6-desoxy-D -talopyranoside] ( 5 ), antiarigenin-3-β-O-[3-O-β-D -gulopyranosyl-β-6-desoxy-D -talopyranoside] ( 7 ), antiarigenin-3-β-O-[4O-β-D -allopyranosyl-β-6-desoxy-D -allopyranoside] ( 8 ), and antiarigenin-3-β-O-β-6-desoxy-D -allopyranoside (antiallosid) ( 9 ). The structure of strophanthidinchinovoside ( 3 ) could be confirmed by synthesis.     

Die Struktur des Harpagosids. 2. Mitteilung über Iridoide

The structure and configuration of harpagoside, a bitter principle from the roots of Harpagophytum procumbens DC, have been elucidated by degradation reactions and NMR. spectra. The hitherto uncertain position of a secondary hydroxyl group could be assigned to C-6 of the aglycone moiety. As earlier postulated, harpagoside ( 1 ) as well as its saponification product, harpagide ( 12 ), belong to a series of natural enol ethers known as iridoids.     

Zur Biosynthese des Strychnins. 135. Mitteilung über Alkaloide

From the feeding of young plants of Strychnos nux-vomica with [¹⁴C]-1-and [¹⁴C]-2-acetate it could be deduced that the C-atoms 22 and 23 were derived from acetate. [¹⁴C]-2-mevalonate, [¹⁴C]-2-geraniol and [¹⁴C]-2-geranyl pyrophosphate were also incorporated into strychnine. The distribution of radioactivity in the «mevalonate-strychnine» was in agreement with the monoterpenoid hypothesis. Feeding experiments especially with [¹⁴C]-tryptophane showed that the main production centre of the alkaloid lay in the roots and that only a small part of it was carried to the leaves. Tritium labelled WIELAND GUMLICH aldehyde as well as N_(a)-[¹⁴C]-1-acetyl WIELAND GUMLICH aldehyde were not converted into strychnine by S. nux-vomica.     

Verbascenin,ein macrocyclisches Spermin-Alkaloid aus verbascum 184. Mitteilung über organische Naturstoffe

Verbascenine, a Macrocyclic Spermine Alkaloid Isolated from Verbascum The new spermine alkaloid verbascenine ( 1 ) has been isolated from extracts of the aerial parts of Verbascum phoeniceum L. and V nigrum L. The structure of the alkaloid was elucidated by chemical degradation and by a study of the spectral properties of the alkaloid and its derivatives. Compared to the 13-membered alter native 7 the 17-membered structure 1 is preferred on the basis of mass spectral arguments.     

Rosafluin,ein neues Diapocarotindiol aus Rosenblüten. 8. Mitteilung über Rosenfarbstoffe

Rosafluine, a Novel Diapocarotenediol from Rose Petals A strongly fluorescent trace compound from rose petals was identified as the as yet unknown 10,10′-diapocarotene-10,10′-diol ( = 4,9-dimethyldodeca-2,4,6,8,10-pentaene-1,12-diol; 2 ).     

Photochemische Erzeugung und Reaktionen des Benzonitril-benzylids. 42. Mitteilung über Photoreaktionen

Photochemical Generation and Reactions of Benzonitrile-benzylide The low temperature irradiation of 2,3-diphenyl-2H-azirine ( 1 ) in DMBP-glass at ?196° has been reinvestigated. It was possible to convert 1 nearly quantitatively into the dipolar species benzonitrile-benzylide ( 3 , Φ₃ = 0,78), which exhibits UV.-absorptions at 344 (? = 48000) and 244 nm (? = 28500) (Fig. 1, Tab. 1). Irradiation of 3 with 345 nm light at ?196° resulted in almost complete reconversion to the azirine 1 (Φ = 0,15; Fig. 2). When the solution of 3 in the DMBP-glass was warmed up to about ?160° a quantitative dimerization to 1,3,4, 6-tetraphenyl-2,5-diaza-1,3,5-hexatriene ( 8 ) occurred. This proves that 8 is not only formed by the indirect route 3 + 1 → 7 \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\longrightarrow }\limits^{hv} $\end{document} 11 → 8 known before (Scheme 1), but also by dimerization of 3 either by direct head to head coupling or via the intermediate e (p. 2675), followed by a fast thermal hydrogen transfer reaction. The occurrence of the dipolar intermediate 11 in the photochemical conversion of the bicyclic compound 7 to 8 could also be demonstrated by low temperature experiments: On irradiation at ?196° 7 gave the cherry red dipolar intermediate 11 (λ_max = 520 nm), which at ?120° isomerizes to 8 . It should be noted, that neither 7 nor 11 are formed by dimerization reactions of 3 . Experiments carried out at room temperature demonstrate, that both processes for the formation of 8 may compete: Irradiation of a solution of 1 (DMBP, c = 8 × 10^?4 to 5 × 10^?3M ) with 350 nm light of high intensity (which does not excite the bicyclic compound 7 ) leads to a relative high photostationary concentration of the dipolar species 3 . Under these conditions the formation of 8 is due to dimerization of 3 (Φ₈ = 0,19). With low light intensity only a very low stationary concentration of 3 can be obtained. Therefore the reaction of 3 with 1 , leading to the bicyclic intermediate 7 , becomes now predominant (Φ_?1 = 1,55, which corresponds with the expected value of 2 × 0,8). Irradiation of 1 at ?130° with 350 nm light of high intensity gives 8 with a quantum yield of 0,44. This is in agreement with the theoretical value Φ₈ = 0,4 for an exclusive formation of 8 by dimerization of 3 . The lower quantum yield for the formation of 8 at room temperature makes probable that under these conditions 3 not only dimerizes to 8 , but also to another, so far unidentified dimer, e.g. 2,3,5,6-Tetraphenyl-2,5-dihydropyrazine. By flash photolysis of a solution of 1 (cyclohexane, c = 10^?4M , 25°) the disappearance of 3 could directly be measured by UV.-spectroscopy: At relative high concentrations (c ≥ 10^?7M ) 3 disappeared according to a second order reaction with the rate constant k = 5 × 10⁷M ^?1S ^?1. At lower concentrations (c ≤ 10^?7M) the rate of disappearance of 3 follows first order kinetics. The rate constant of this pseudo first order reaction ( 3 + 1 → 7 ) has been determined to be 1 → 10⁴M^?1S^?1. Using Padwa's table of relative rates for the cycloaddition of the dipolar species 3 to various dipolarophiles, including the azirine 1 , an absolute rate constant of k ≈ 8 × 10⁸M ^?1S ^?1 for the addition of 3 to the most active dipolarophile fumaronitrile could be estimated. In cyclohexane at room temperature, the diffusion controlled rate constant equals 6,6 × 10⁹M ^?1S ^?1. In Table 1 the UV.-maxima of several nitrile-ylides, among them a purely aliphatic one, are given.     

Synthese der vier stereoisomeren Dihydropalustraminsäuren. 13. Mitteilung über Schachtelhalmalkaloide

Syntheses of the four stereoisomeric dihydropalustramic acids ([6-(1-hydroxypropyl)-2-piperidyl]acetic acids) (?)-Dihydropalustramic acid, a key product in the structure elucidation of the alkaloid palustrin, has been assigned the threo-cis structure 20 by comparison with the four stereoisomeric (±)-dihydropalustramic acids (threo-cis, threo-trans, erythro-cis, erythro-trans). The latter were synthesized by a new route to α, α′-di-substituted piperidines of this type. Ring closure to the piperidine ring with simultaneous stereospecific formation of the hydroxylated side chain has been achieved by reaction of the stereoisomeric methylesters of 7,8-epoxy-2-decenoic acids with benzylamine. Assignment of the configuration at the piperidine ring is based on careful comparison of the H-NMR. spectra of the N-benzylpiperidines and with the help of lanthanide shift reagents.     

Über Juliprosin,ein weiteres Alkaloid aus Prosopis julifloraA.DC. 180. Mitteilung über organische Naturstoffe

Juliprosine, a Further Alkaloid Isolated from Prosopis juliflora A .DC . By catalytic hydrogenation of the second base juliprosine ( 2 ) isolated from Prosopis juliflora (Leguminosae) the hexahydroderivative 5 was formed. The same product was obtained also by catalytic hydrogenation of juliprosopine ( 1 ) of known structure. The absolute configuration of 2 was deduced by comparison of [M]_D values of Prosopis alkaloids of known absolute configuration.     

Panicutin,ein neues Alkaloid aus Aconitum paniculatum LAM. 4. Mitteilung über Aconitum

Panicutin, a New Alkaloid from Aconitum paniculatum LAM. A new diterpene alkaloid, which we named panicutine ( 2 ), was isolated from the paniculatine-containing chemovariety of Aconitum paniculatum LAM. Investigation by spectral methods showed that 2 has the formula C₂₃H₂₉N₄₄ and belongs to the hetidine ( 1 )-type alkaloids. It has one acetoxy group at C(2) and one carbonyl group each at C (6) and C (11).     

Anil-Synthese 22. Mitteilung über die Herstellung von Styryl-und Distyryl-Derivaten des Pyridins

Preparation of Styryl and Distyryl Derivatives of Pyridine 2,4-, 2,5- and 2,6-Dimethylpyridines react with anils of aromatic aldehydes in the presence of dimethylformamide and potassium hydroxide to yield the corresponding distyrylpyridines (‘anil synthesis’). Under the same reaction conditions (4-methylstyryl)pyridines are converted to (stilbenylvinyl)pyridines. Similarly, the Schiff's base derived from pyridine-3-carbaldehyde and p-chloroaniline on treatment with methyl- and p-tolyl-substituted aromatic heterocycles gives the corresponding (heteroaryl-styryl)pyridines, whereas with the Schiff's bases derived from pyridine-2- and -4-carbaldehyde side reactions, such as dimerization followed by disproportionation predominate.     

Über die chemische Konstitution der mit Divinylsulfon vernetzten Cellulose. 12. Mitteilung über textilchemische Untersuchungen

Cotton and viscose fibres treated with divinyl sulphone under alkaline conditions were degraded in sulphuric acid. By column chromatography degradation products have been identified which contain two glucose units on mono- and dimeric sulphone derivatives, i.e. glucose ethers of 2,2′-dihydroxyethylsulphone and of 2,2′-bis-(hydroxyethylsulphonyl)-diethylether. This is the first direct chemical proof of the existence of cross-linkages in cellulose treated with bifunctional reagents.     

über Verbindungen des Thoriums mit Stickstoff und Wasserstoff

Preparation and Vibrational Spectra of N-Trimethylsilyl-Tris(trimethylsiloxy)-Vanadium (V) imine, (Me₃SiO)₃V?N? SiMe₃ The preparation of the title compound from VOCl₃ and hexamethyl-disilazane is described. The vibrational spectra of the compound suggest a vanadium-nitrogen triple bond and a near linear vanadium–nitrogen–silicon arrangement.     

Umbellamin,ein neues «dimeres» Indolalkaloid 130. Mitteilung über Alkaloide [1]

Umbellamine (f; C₄₁H₄₈N₄O₄), a «dimeric» indole-indoline alkaloid, was isolated from the root bark of Hunteria umbellata (K. SCHUM .) HALL . F.; it is probably identical with the alkaloid hunterine (structure unknown) of NeUSS & CONE [14]. Thermolysis yielded (+)-eburnamenine (II), whereas a detailed mass spectrometric study of I, of its O-methyl and O-acetyl derivatives, and also of the derived diol V revealed the presence of a phenolic hydroxy-pseudoakuammigine group as second part, the benzene nucleus of the latter being linked to the C-14 atom of the eburnamenine component (present in the dihydrom form). The n.m.r. study of umbellamine and of its derivatives showed that the phenolic hydroxy group is either at C-10′ or C-11′ and that the dihydroeburnamenyl residue is connected to C-11′ or C-10′ of the pseudoakuammigine residue. A choice between these alternatives was possible by investigation of the hydroxylated base IX arising from the latter component, and obtained in small quantities by treatment of umbellamine with zinc or tin in acid. Its constitution, deduced by uv., n.m.r. and mass spectrometry, suggested that the hydroxy group is fixed at C-11′. If this is correct, the dihydrocburnatnenyl residue is linked to C-10′ of the pseudoakuarnmigine residue. Thus we propose formula I for umbellamine.     

Photochemische Cycloadditionen von 3-phenyl-2h-azirinen mit Aldehyden. 31. Mitteilung über Photoreaktionen

Experiments concerning the photochemical condensation of 3-phenyl-2H-azirines 1 with aliphatic and aromatic aldehydes to 3-oxazolines 4 are fully described (cf. scheme 1 ). Photochemically nitrile methylides of type 2 are first formed, which then very quickly react thermally with the aldehydes in a regiospecific manner to give the 3-oxazolines 4 . Azirines monosubstituted in position 2 (l b and 1 c ) give mixtures of cis, trans-oxazoline isomers, in which the cis isomer predominates. The stereoselectivity of the cycloaddition reaction can be rationalized by a simple model (scheme 10). The stereoisomeric 3-oxazolines 4 are distinguishable in the NMR. spectra by the large homoallylic coupling constants between the H atoms on C(2) and C(5).     

Magnetische Kernresonanz-Untersuchungen über die struktur der Komplexe aus Nitroaromaten mit azid-ionen 9. Mitteilung über nucleophile aromatische Subsitutionsreaktionen [1]

1. NMR. spectra of solutions of tetraethylammonium azide and 2,4,6-trinitro;benzene derivatives (methyl picrate, picryl chloride and picryl azide, respectively) demonstrate that the reactants probably form σ complexes.     

Oxydative Kupplung von Indolinen und 1,2,3,4-Tetrahydrochinolinen mit Kaliumpermanganat. 153. Mitteilung über Alkaloide

It is shown that treatment of indolines like 4a-methyl-1,2,3,4,4a,9a-hexahydrocarbazole ( 1 ) and even indoline-alkaloids like 5 or 6 (cf. scheme 1) with KMnO₄ in boiling acetone solution leads to the indolenines 10, 29 and 33 , respectively, and, in relatively high yields, to N,N′- or C,N-coupling products (cf. schemes 2 and 5). The results of the oxidation of 6- or 8-methoxy-indolines are shown in schemes 3 and 4, respectively. Analogous ‘dimeric’ dehydrogenation products are observed when tetrahydroquinolines ( 8 and 9 , resp.) are treated with KMnO₄ (cf. schemes 7 and 8, resp.). The formation of the bis-compounds is almost certainly due to the coupling of two intermediate indolenyl or tetrahydroquinolyl radicals. The cleavage of the hydrazine derivatives 11 or 17 (scheme 9) also leads to ‘dimeric’ C,N-coupling products. By heating the hydrazine derivative 17 with aqueous HCl, a complete cleavage into indoline 2 and the indolenines 16 and 20 is observed. The reaction is rationalized in scheme 10. So far no naturally occurring alkaloids related to the above mentioned C,N-coupling products have been found.