Die Konstitution des Alkaloides Juliprosopin aus Prosopisjuliflora A. Dc. 176. Mitteilung über organische Naturstoffe

The Structure of the Alkaloid Juliprosopine from Prosopis juliflora A. Dc. A new alkaloid, juliprosopine, has been isolated from Prosopis juliflora A. Dc. (Leguminosae), for which structure 1 is proposed. The piperidine moiety could be elucidated on the basis of spectroscopic data (MS., ¹H-NMR., ¹³C-NMR.) of juliprosopine and the derivatives 2–4 . The central hexahydroindolizine part and its substitution pattern has been determined mainly on the bases of the Hofmann-degradation product 11 , which yielded the hydrogenation products 13 and 14 . By ozonolysis 11 was converted to 16 and 18 . It is proposed that juliprosopine was built up in nature by two ‘monomeric’ Prosopis alkaloids and one dihydropyrrol unit.     

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.     

A New Iridoid Alkaloid from the Flowers of Plumeria rubra L. cv. acutifolia

A new iridoid alkaloid containing a spirolactone unit, plumericidine ( 1 ), was isolated from the flowers of Plumeria rubra L. cv. Acutifolia. Its structure was elucidated by spectroscopic evidence and confirmed by X‐ray diffraction crystallography. Its anticancer and antiviral activities were evaluated, but found to be insignificant.     

Syntheses based on norfluorocurarine. 3. Structures of (−)-norfluorocurarine, (±)-norfluorocurarine,and fluorocurarine

Structures of the alkaloids (−)-norfluorocurarine, its racemate (±)-norfluorocurarine from Vinca erecta, and fluorocurarine obtained by N(β)-methylation of (−)-norfluorocurarine were established by x-ray crystal structure analyses. The alkaloid crystallized with two molecules in the asymmetric unit for the first two crystals. The asymmetric unit of (±)-norfluorocurarine crystal consisted of two antipods. The asymmetric unit in the crystal of the last compound consisted of the N(β)-methylated cation and a hydroxide anion. The formation of bimolecular associates through intermolecular N–H…O H-bonds was typical of these crystal- line structures. An associate in the crystal structure of fluorocurarine involved two hydroxide anions.     

Violatinctamine, a new heterocyclic compound from the marine tunicate Cystodytes cf. violatinctus

A new alkaloid designated violatinctamine and four known metabolites were isolated from the tunicate Cystodytes cf. violatinctus collected in Kenya. Violatinctamine has a unique heterocyclic skeleton, which combines a benzothiazole unit and a dihydroisoquinoline unit. The structure of violatinctamine was elucidated by interpretation of MS results as well as 1D and 2D NMR spectra of the alkaloid and of its O,O′-dimethyl derivative. Analysis of the spectral information also implies that violatinctamine exists as a mixture of two tautomers—the imino-phenol and the amino quinone-methide.     

Indolalkaloids of Pleiocarpa talbotii Wernham. 145. Alkaloids

Besides talbotine ( 1 ) three new indole alkaloids, talpinine ( 2 ), talcarpine ( 3 ) and 16-epi-affinine ( 4 ) were isolated from the stem bark of Pleiocarpa talbotii Wernham. The structure of 2 was deduced by chemical degradation and by analyses of the spectra of the alkaloid and its derivatives. One of these derivatives is identical with talcarpine ( 3 ). The structures 2 and 3 are similar to that of macroline ( 14 ), a splitting product of the bisindole alkaloid villalstonine from Alstonia species. 16-epi-Affinine ( 4 ) was chemically correlated with the known alkaloid vobasine ( 19 ). Talpinine ( 2 ) and 16-epi-affinine ( 4 ) were also isolated from the root bark of Pleiocarpa talbotii.     

Alkaloids of Arundo donax L. 13. The structure of a new dimeric indole alkaloid,arundanine

The structure of a new dimeric indole alkaloid, named arundanine, isolated from the roots of Arundo donax L. (Poaceae), was elucidated. Arundanine was identified as 3-(N,N-dimethylaminoethyl)-4-[3-(N,N-dimethylaminoethyl)indole-1-yl]-5-hydroxyindole on the basis of spectroscopic data and the transformation into the known alkaloid, arundamine.     

Macrocarpamin,ein neues Bisindolalkaloid aus Alstonia macrophylla WALL. 167. Mittelung über organische Naturstoffe

Macrocarpamine, a new bisindole alkaloid from Alstonia macrophylla WALL . A new bisindole alkaloid give the name (?)-macrocarpamine ( 3 ) was isolated from the bark of Alstonia macrophylla WALL . Under pyrolytic conditions 3 is cleaved into the two known bases (+)-pleiocarpamine ( 2 ) and (?)-anhydro macrosalhin-methin ( 5 ) (Scheme 1). The structure of 3 (including relative configuration) was deduced on the basis of chemical evidence and from its UV.-, IR.-, NMR.- and mass spectroscopic data.     

Kopsirachin,ein ungewöhnliches Alkaloid aus der Apocynaceae Kopsia dasyrachis Ridl. 189. Mitteilung über organische Naturstoffe

Kopsirachine, an Unusual Alkaloid from the Apocynaceae Kopsia dasyrachis Ridl. From the leaves of Kopsia dasyrachis Ridl. a new type of alkaloid, kopsirachine ( 1 ), built up from catechin ( 2 ) and skytanthine ( 3 ) has been isolated. The structure elucidationis based on spectral and chemical evidence. Oxidative cleavage of its derivative 4 with KMnO₄ afforded veratric acid wich was identified as its methylester by comparison with an authentic sample. Pyrolysis of 1 yielded δ-skytanthine ( 3 ). The stereochemistry of the skytanthine substituents in 1 could not yet be established.     

Peduncularistin,Triabunnin und Aristolarin,drei neue Indolalkaloide aus Aristotelia peduncularis (LABILL.) HOOK. F., 191. Mitteilung über organische Naturstoffe

Peduncularistine, Triabunnine and Aristolarine, Three Ne Indole Alkaloids from Aristotelia peduncularis (L_LABILL.) H_OOK, F. Peduncularistine ( 1 ), triabunnine ( 2 ) and aristolarine ( 3 ), three new indole alkaloids, have been isolated from Aristotelia peduncularis (L_ABILL.) H_OOK. F.; the structure and absolute configuration of 1 were elucidated on the basis of spectroscopic data and confirmed byt transformation of 1 into aristeserratine ( 4 ), a known alkaloid isolated from the same plant. The proposed structure 2 for the second alkaloid and its absolute configuration were established but spectroscopic means and by partial synthesis from 4 . The relative configuration of 3 was postulated on the basis of spectroscopic and biogenetic arguments.     

Argininosecologanin,a secoiridoid-derived guanidine alkaloid from the roots of Lonicera insularis

A new secoiridoid-derived guanidine alkaloid, argininosecologanin (1), along with 12 known iridoids and secoiridoids (2–13), was isolated from the roots of Lonicera insularis. The structures of the isolated compounds were established by the spectroscopic analysis and comparison of their spectral data with previously reported data. Compound 1 was assigned as the first secoiridoid-derived guanidine alkaloid isolated as a natural product. A plausible biogenetic pathway for 1 is suggested based on its structural similarity to (E)-aldosecologanin (4).     

Three New Alkaloids from Hippophae rhamnoides Linn. subsp. sinensis Rousi

Two novel organic amide alkaloids, 4‐[(E)‐p‐coumaroylamino]butan‐1‐ol ( 1 ) and 4‐[(Z)‐p‐coumaroylamino]butan‐1‐ol ( 2 ), together with a rare pyridoindole alkaloid, hippophamide ( 3 ), were isolated from the seed residue of Hippophae rhamnoides Linn . subsp. sinensis Rousi . Their structures were determined by spectroscopic means. The results show that compounds 1 and 2 are (E/Z)‐isomers, compound 3 , a pyridoindole alkaloid concerted with γ‐lactam ring.     

Alkaloids from Arundo donax. XVII. Structure of the Dimeric Indole Alkaloid Arundaphine

The newdimeric alkaloid arundaphine, a tryptamine-tryptamine base, was isolated from roots and rhizomes of Arundo donax (Poaceae). Spectral data and an x-ray structure analysis established its structure as 1-[3-(2-dimethylaminoethyl)-5-hydroxy-1H-4-indolyl]-3-hydroxy-3-(2-methylaminoethyl)-2-indolinone.     

Macrocyclische Spermidinalkaloide aus Maytenus tnossambicensis (KLOTZSCH) BLAKELOCK 12. Mitteilung über Celastraceen-Inhaltsstoffe

Macrocyclic Spermidine Alkaloids from Maytenus mossambicensis (KLOTZSCH) BLAKELOCK In addition to celabenzine ( 1 ), three new macrocyclic spermidine alkaloids cyclocelabenzine ( 2 ), isocyclocelabenzine ( 3 ) and hydroxyisocyclocelabenzine ( 4 ) have been isolated from Maytenus mossambicensis (klotzsch) blakelock, var. mossambicensis. The three alkaloids show the 13-membered lactam ring of celabenzine being linked to the benzoyl residue within the spermidine unit. Hydroxyisocyclocelabenzine ( 4 ) is the first known spermidine alkaloid with a hydroxy function at the macrocyclus. The structural elucidation was based mainly on spectroscopic methods, specially ¹H- and ¹³C-NMR. spectroscopy.     

Crystal Structure of Akuammigine Picrate Hydrate

The single‐crystal X‐ray data of akuammigine picrate hydrate ( 1 ?Picr?H₂O) confirm the relative configuration of the indole alkaloid akuammigine ( 1 ) as epiallo (Fig. 1). With reference to the known (15S)‐configuration due to biosynthesis, the absolute configuration of the other stereogenic centers is thus given by (3R,19S,20S). Four crystallographically independent molecules are observed in the asymmetric unit (Fig. 2). Each of the alkaloid cations forms H‐bonds to a H₂O and a picrate anion (Fig. 3). The H₂O molecules are further associated by a H‐bond as indicated by the short O???O distance (Table 2). The conformation in the solid state of the picrate hydrate is now firmly established, and a cute H‐bonding motif is observed.     

A new norditerpenoid alkaloid acsonine from the roots of Aconitum kusnezoffii Reichb.

The known norditerpenoid alkaloid mesaconitine and a new alkaloid acsonine 1 were isolated from the roots of Aconitum kusnezoffii Reichb. The structure of 1 was established based on spectroscopic data.     

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.     

Die Struktur des Spermin-Alkaloides Aphelandrin aus Aphelandra squarrosa NEES. 170. Mitteilung über organische Naturstoffe

The structure of the spermine alkaloid aphelandrine from Aphelandra squarrosa NEES The new spermine alkaloid aphelandrine ( 2 ) has been isolated from Aphelandra squarrosa NEES . By oxidation of 2 with KMnO₄ followed by methylation (CH₂N₂) 12 and 14 could be prepared (Scheme 2). Fusion of 2 with KOH yielded spermine ( 1 ) whereas hydrolysis of 2 in hot hydrochloric acid results in lacton 17 , the structure of which could be elucidated by comparison with a synthetically prepared model compound (Scheme 3). The benzylic bonds N (10), C(11) as well as O(16), C(17) of 2 could be cleaved by hydrogenolysis (compare 23 and 26 ; Scheme 4). The elucidation of the correct linkage of the spermine moiety with the aromatic dicarboxylic acid is based mainly on chemical and spectroscopic evidence of the tetrahydro derivative 26 , the Hofmann-degradation products 28 , 30 and 31 (Scheme 6) as well as the ester 35 , prepared by partial hydrolysis of 2 (Scheme 7).     

Hypepontine,a new quaternary alkaloid with antimicrobial properties

Abstract

New isoquinoline alkaloid hypepontine (1) together with a five known compounds, were identified in Hypecoum ponticum Velen, the partial synonym of Hypecoum procumbens L. The structure of the new substance was elucidated based on spectroscopic evidence. The tertiary and quaternary alkaloid mixtures as well as the isolated alkaloids were evaluated for their antibacterial and antifungal activity. The result revealed that the crude alkaloid mixture containing quaternary isoquinoline alkaloids showed potent antifungal and antibacterial activity.     

Über die Konstitution zweier neuartiger «dimerer» Indolalkaloide Pycnanthin und Pleiomutinin 132. Mitteilung über Alkaloide

The «dimeric» indole alkaloid (+)-pycnanthine ( 2 ) has been isolated, along with (+)-pleiocarpamine, (+)-quebrachamine, (+)-macusine B and an unknown alkaloid D from Pleiocarpa pycnantha (K. SCHUM .) STAPF , var. pycnantha M. PICHON. An investigation of its chemical and spectroscopic properties has led to the determination of structure 2 for this base. Its 6′,7′-dihydro derivative has been shown to be identical with the alkaloid pleiomutinine, previously isolated from Pleiocarpa mutica BENTH .