Über die Struktur der makrocyclischen Spermidin-Alkaloide Oncinotin,Neooncinotin und Isooncinotin. 151. Mitteilung über Alkaloide

Three spermidine alkaloids – oncinotine ( 1 ), neooncinotine ( 3 ), and isooncinotine ( 2 ) – have been isolated from the stem bark of Oncinotis nitida BENTH . (Scheme 1); 1 and 3 are so far an unseparable mixture. However, by treatment of this mixture with K-t-butoxide, neooncinotine is completely converted into isooncinotine, and oncinotine, the main alkaloid, is obtained in pure form. The structural assigment of these alkaloids is based on chemical and spectral evidence. Thus oncinotine ( 1 ) has been degraded via 24 (Scheme 4) and 32 to the putrescine derivative 35 and the piperidine derivative 34 (Scheme 5). Similarly neooncinotine ( 3 ) and isooncinotine ( 2 ), have given 34 along with the 1, 3-diaminopropane derivative 36 (Scheme 5). The major decomposition pathways of 24 , 35 and 36 in the mass spectra are described in Schemes 8, 6 and 7 respectively. The absolute configuration of 1 , 2 and 3 is derived by chiroptical correlations with (R)-(?)-N-methylconiine ( 38 ).     

Indolalkaloide aus Conopharyngia durissima STAPF. 134. Mitteilung über Alkaloide [1]

The alkaloids akuammiline ( 1 ) and anhydrovobasindiol ( 6 ) were isolated from the trunk bark of the Apocynacea Conopharyngia durissima STAPF . The structure of the unknown base anhydrovobasindiol was elucidated and this base was partially synthetised from the alkaloid vobasine. The well-known akuammiline could be correlated by LiAlH₄ reduction to picralinol ( 4 ).     

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 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 das Alkaloid Lonicerin aus Callichilia barteri. 137. Mitteilung über Alkaloide

The alkaloid lonicerine was isolated from Callichilia barteri (Apocynaceae). By chemical and spectroscopic evidence it could be shown to be 16-epi-aspidodasycarpine ( 1 ).     

Über die Struktur eines neuartigen Indolalkaloids,des Talbotins. 141. Mitteilung über Alkaloide [1]

From the leaves of the African Apocynacea Pleiocarpa talbotii Wernham a novel indole alkaloid, talbotine, C₂₁H₂₄N₂O₄, has been isolated. Talbotine ( 1 ) contains a secondary N_(b)-atom and a cyclic hemiacetal group. Catalytic hydrogenation leads to 19, 20-dihydrotalbotine ( 6 ), hydrogenation in the presence of formaldehyde gives N_(b)-methyl-19, 20-dihydrotalbotine ( 8 ). In the presence of sodium methoxide and methanol, 1 is converted into the lactone 12 and the methyl ester 13 . In these reactions carbon 17 is lost as formic acid. These data, together with the analyses of the NMR. spectra of talbotine and its derivatives as well as the interpretation of the various types of the mass spectral fragmentation, lead to formula 1 for the alkaloid. Dehydrogenation of talbotine methyl ether ( 3 ) with palladium and maleic acid gives the ß-carboline derivative 26 . The N_(b)-methiodide of the latter is converted into N_(b)-methyl-talbotine methyl ether on reduction with sodium borohydride. From these data as well as from the analyses of NMR. and IR. spectra the complete relative stereochemistry of talbotine could be derived. Application of the Horeau method to the nitrogen atom b of the methyl ether 3 on the one hand and to the hydroxyl group on C17 in N_(b)-methyl-19, 20-dihydrotalbotine ( 8 ) on the other hand gives consistent results and establishes S configuration of centre 15.     

Über Alkaloide aus Laurelia novae-zelandiae A. CUNN. 5. Mitteilung über natürliche und synthetische Isochinolinderivate

From an extract of Laurelia novae-zelandiae A. CUNN . the aporphine alkaloids (?)-pukateine (I), (?)-pukateine methyl ether (II), (?)-roemerine (IV), (?)-mecambroline (V), (+)-boldine (VII), (+)-isoboldine (VIII), (+)-laurolitsine (IX), and the proaporphine alkaloid (+)-stepharine (X) were isolated. Compounds II and V were up to now not described as natural alkaloids. These and the alkaloids IV, VII, VIII, IX and X are new for L. novae-zelandiae.     

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.     

Die Alkaloide von Gabunia eglandulosa STAPF 155. Mitteilung über Alkaloide

From the root bark of the Apocynaceae Gabunia eglandulosa STAPE seven indole alkaloids were isolated. Besides the known indole alkaloids (?)-isovoacangine ( 1 ), (?)-coronaridine ( 2 ), voacamine ( 3 ), vobasine ( 4 ), and perivine ( 5 ), two new bases (?)-19-hydroxy-isovoacangine ( 6 ) and 19-hydroxy-coronaridine ( 15 ) were isolated. Compound 6 was obtained by oxidation of isovoacangine with iodine. Similar oxidation reactions with voacangine ( 12 ) were studied.     

Massenspektrometrische Identifizierung und Synthese isomerer und homologer Spermidin- und Spermin-Derivate. 25. Mitteilung über das massenspektrometrische Verhalten von Stickstoffverbindungen. 161. Mitteilung über Alkaloide

Synthesis of isomeric and homologous spermidine and spermine derivatives and their identification by mass spectrometry. The structure of homologous and isomeric spermidines and spermines follows from mass-spectroscopical analysis of their peracetyl (see text, footnote 3) (Table 1) or tosyl-acetyl (Table 2) derivatives. In the case of the peracetyl compounds, triads of peaks are recorded which, according to the number of methylene groups between the nitrogen atoms, show mass numbers characteristic for each of the substances (Scheme 1, ions b , d , e and c ). On the basis of cyclic ions of type f (Scheme 2), occurring in the mass spectra of N-acetyl derivatives, tosylated on a secondary amino nitrogen atom, deductions can be drawn as to the number of methylene groups between neighbouring tosylated and acetylated nitrogen atoms in these compounds.     

Indolalkaloide aus Kopsia dasyrachis Ridl. 185.Mitteilung über organische Naturstoffe

Indole Alkaloids of Kopsia dasyrachis Ridl. From the leaves of Kopsia dasyrachis Ridl. three new indole alkaloids, kopsidasine-N-oxide ( 1 ), kopsidasine ( 2 ) and kopsidasinine ( 3 ) have been isolated. Reduction of 1 with SO² afforded 2 ; treatment of 2 with m-chloroperbenzoic acid gave 1 . The structure elucidation of 1 and 2 , and the deternmination of their relative configurations are based mainly on the correlation of derivative 6 with the known ring skeleton of pleiocarpine ( 9 ) (Scheme 1). The structure of 3 has been established via its Hofmann degradation product 13 also prepared by treatment of 2 with CH₃I (Scheme 3).     

Über die Wanderung der Carboxylatgruppe bei der Benzilsäureumlagerung. 26. Mitteilung über Reduktone und Tricarbonylverbindungen

The benzilic acid rearrangement of ethyl α,β-dioxo-butyrate was studied by NMR.-and UV.-techniques. In weak alkaline media (pH < 10) the ester group is hydrolyzed first, then the carboxylate group migrates to form methyltartronate. The migration of the carboxylate group was proved by radioactive labeling. At higher pH-values (pH > 11,5) the intakt ester group migrates, with ester hydrolysis occuring as a second step.     

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.     

Magnetische Kernresonanz- und «Molecular Orbital»- untersuchungen über die struktur von MEISENHEIMER-komplexen 8. Mitteilung über nucleophile aromatische Substitutionsreaktionen [1]

(1) The NMR. spectra of the stable methoxide addition complexes of 2,4-dinitro-, 2,4,6-trinitro- and 2,4-dinitro-6-cyano-anisole, and the intramolecular (spiro) reaction product of 1-(2′-hydroxyethoxy)-2,4,6-trinitrobenzene demonstrate that these products are MEISENHEIMER (σ?) complexes (addition of base in position 1).     

Indolalkaloide aus den Blättern von Hedranthera barteri (Hook. f.) Pichon. 146. Mitteilung über Alkaloide

From the leaves of the West African plant (Apocynaceae Hedranthera barteri) has been isolated the phenolic (?)-desmethyl-vobtusine ( 3 ), alongside the already known bisindole alkaloids (?)-goziline ( 1 ) and (?)-vobtusine ( 2 ). The new alkaloid 3 has been spectroscopically characterised and correlated with (?)-vobtusine ( 2 ). Furthermore, the ‘monomeric’ alkaloids (?)-hedrantherine ( 4 ) and (?)-17-hydroxy-hedran-therine ( 5 ) were found in the leaves of H. barteri. Both of these alkaloids contain a cyclic semiacetal group. These bases and their derivatives possessing an unchanged β-anilinoacrylester group show, in the mass spectrometer, the same characteristic fragmentation as vincadifformine ( 11 ), whilst their 2,3-dihydroderivatives bear more of a resemblance to aspidospermine. From the strongly negative Cotton effect of 4 and 22 at 300–350 nm follows the absolute configuration in these bases of centre 12. Hedrantherine ( 4 ) represents the lower half of the bisindole type of vobtusine bases. The upper half has previously been encountered in form of the alkaloid beninine in the rootbark of H. barteri.     

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.     

Notiz zur Konstitution des Laurepukins. 8. Mitteilung über natürliche und synthetische Isochinolin-Derivate

The alkaloid (?)-laurepukine is shown to possess one of the epimeric N-oxide structures 4 or 5 . Oxidation of (?)-pukateine ( 3 ) by hydrogen peroxide gives (?)-laurepukine and, as a second product, 6-epi-laurepukine.     

Die Konstitution der Melodinus-Alkaloide (+)-Meloscin, (+)-Epimeloscin und (+)-Scandin. 1. Mitteilung über Alkaloide aus Melodinus scandens FORST

For the alkaloids meloscine, epimeloscine and scandine, isolated from the Apocynacee Melodinus scandens FORST ., the structures 1, 10 and 11 , respectively, are deduced. Scandine is proved to possess the relative configuration as shown in 11 r. For meloscine and epimeloscine the relative configurations as depicted in 1 r and 10 r are discussed.