Aromatic alkaloids

Arecoline 40, 71, 86, 208, 209 Arginine-derived alkaloids 62 Aromatic alkaloids 10 Arosine 22 Arthropod alkaloids 6 Arundacine 8, 38 Arundamine 8, 38 Aspidoalbine 16, 38 Aspidolimidin 16, 68 Aspidolimidine 16... 

Utkina, N. K. (2009). Antioxidant activity of aromatic alkaloids from marine sponges Aaptos aaptos and Hyrtios sp. Chem. Nat. Compd. 6, 849-853. 

The marine hydroid Tridentata marginata contained the aromatic alkaloids tridentatols A-C (186-188). Tridentatol A (186) inhibited feeding by the planehead filefish. The structure of tridentatol C (188) was elucidated by a single crystal X-ray diffraction study [179]. 

Nakahara S, Matsui J, Kubo A (1998) Synthesis of Pantherinine, a Cytotoxic Fused Tetracyclic Aromatic Alkaloid. Tetrahedron Lett 39 5521... 

Fused tetra- and pentacyclic aromatic alkaloids are a new, emerging group of compounds from marine organisms. Amphimedine (187) was isolated from a Pacific sponge (Amphimedon sp.) as a cytotoxic compound in 1983 and was the first example of a polycyclic alkaloid (158). A pigment from the sea anemone Calliactis parasitica, named calliactine, has been known for many years, but the structure elucidation of calliactine was a difficult problem (159). In 1987 the structure of calliactine was proposed to be 188 on the basis of modern spectroscopic methods as well as chemical... 

Two pentacyclic aromatic alkaloids, plakinidines A (217) and B (218) were recently isolated from a Vanuatuan red sponge of the genus Plakortis... 

Kobayashi, J., Cheng, J. F., Walchli, M. R., Nakamura, H., Hirata, Y., Saski, T., and Ohizumi, Y., Cysodytins A, B, and C, novel tetracyclic aromatic alkaloids with potent antineoplastic activity from the Okinawan tunicate Cystodytes dellechiajei, J. Nat. Prod., 53, 1800, 1988. 

The preferential cleavage of the middle of three vicinal methoxy groups with mineral or Lewis acids has been demonstrated for various aromatic alkaloidal systems (410, 411). Selective ether cleavage of mescaline and trichocereine thus... 

During the last decade a series of structurally fascinating and biologically active fused polycyclic aromatic alkaloids has been isolated from marine sources. One such alkaloid, pan-therinine, has recently been synthesized using the Suzuki reaction (Eq. (32)) [62]. 

The stachybotrins A and B (11) and (12), two new aromatic alkaloids with antibacterial and antifungal activity, were isolated from an aquatic isolate of a new species of the genus Stachybotrys... 

Thus, Ghosez et al. were successful in showing that A,iV-dimethyl hydrazones prepared from a,/3-unsaturated aldehydes react smoothly in normal electron demand Diels-Alder reactions with electron-deficient dienophiles [218, 219]. Most of the more recent applications of such 1-aza-l,3-butadienes are directed towards the synthesis of biologically active aromatic alkaloids and azaanthra-quinones [220-224] a current example is the preparation of eupomatidine alkaloids recently published by Kubo and his coworkers. The tricyclic adduct 3-19 resulting from cycloaddition of naphthoquinone 3-17 and hydrazone 3-18 was easily transformed to eupomatidine-2 3-20 (Fig. 3-6) [225]. 

T160 81T241>, the synthesis also constitutes a formal synthesis of this fully aromatic alkaloid <06JOC1746>. 

Reduction of the cis lactam 61 with LAH afforded the cis amine 60, which was also obtained from either oxidative photocyclization of the enamide 56 or nonoxidative photocyclization of the bromoenamide 56, followed by successive reductions. Oxidative photocyclization of the enamide 56 in the presence of iodine afforded the corresponding dehydrolactam 59 in good yield, which is a useful intermediate for further conversion to various aromatized benzo[c]phenanthridines, the basic structure of many aromatic alkaloids (19,20). 

Kessar et al. (88) described the first photocyclization of (2-bromoben-zoyl)-l-naphthylamine, which was successfully applied to the synthesis of some aromatic alkaloids of this group (Scheme 40). 

Synthesis of the fully aromatized alkaloids can be classified by the patterns of substituents, mostly the methoxyl and methylenedioxy groups, namely, the 2,3,7,8-tetrasubstituted and 2,3,8,9-tetrasubstituted alkaloids. 

Pentacyclic aromatic alkaloid Amphicarpa meridiana CHCl3-MeOH-5% HCl (5 5 3) HSCCC... 

A two-phase solvent system composed of chloroform-methanol-dilute inorganic acid has been used for the separation of a variety of alkaloids including isoquinoline alkaloids, naphthyl-tetrahydroisoquinoline alkaloids, fla-vonoid alkaloids, pentacyclic aromatic alkaloids, diterpenoid alkaloids, aporphine alkaloids, etc. The following example illustrates a typical systematic solvent selection for the separation of palmatine, berberine, epiberberine, and coptisine from the crude alkaloids of Coptis chinensis Franch by analytical HSCCC. In Fig. 1, nine chromatograms are arranged in such a way that the effects of the concentration of HCl (0.3-0.1 M) and the relative volumes of methanol (4 3 2-4 1.5 2, v/v) on the separation of alkaloids from C. chinensis Franch are each readily observed. As the concentration of HCl is reduced from 0.3 to 0.1 M in the solvent system, the retention time... 

Erysotrine (le) does not occur naturally but is a common transformation product of the other aromatic alkaloids. In addition to the members shown, two dihydroderivatives occur in nature dihydroerythraline (erythramine) and dihydroerysodine. 

The above syntheses of the parent spiroamine system establish the skeleton of the aromatic alkaloids. A synthesis of a derivative of jS-erythroidine (III) with the intact spiro skeleton, achieved in Boekel-heide s laboratory (15), provides similar confirmation for the lactonic alkaloids. 

All of the aromatic alkaloids (except for erythratine) and -erythroi-dine possess two asymmetric carbon atoms—the spiro carbon (C-5) and the carbon substituted by methoxyl (C-3). a-Erythroidine has an additional center of asymmetry at C-12. Chemical, spectroscopic, and crystallographic methods have been used to assign relative and absolute configurations at the asymmetric centers. 

No determination of absolute configuration of any of the aromatic alkaloids by X-ray methods or direct chemical correlations has been made. One way in which this might be accomplished would be to interrelate one of them wdth the erythroidines, but attempts (23) to convert both groups to a common degradation product have not been successful. 

The South Pacific and Caribbean sponges Amphimedon sp. and Petrosia sp. are the source of fused aromatic alkaloids sharing a common carbon skeleton, amphimedine (115), isolated by Schmitz and coworkers (89), and petrosamine (116), reported by Faulkner s group (90). The structure of amphimedine was secured by two-dimensional NMR techniques, in particular the natural abundance 13C- 3C coupling correlation experiment, INADEQUATE. Amphimedine was isolated by Soxhlet extraction of the freeze-dried sponge with chloroform. Silica gel and... 

Several reviews affirm the invaluable role played by the Pictet-Spengler cyclization in the assembly of almost every class of aromatic alkaloids. " In this section, we focus on recent examples and pay par-... 

Normal phase LLC—anilines, glycols, alcohols, phenols, aromatics, alkaloids, plasticizers, dyes, pesticides, steroids and metal complexes. 

Comparison of the reduction products formed from the aromatic alkaloids and the dienone alkaloids with sodium boro-hydride in ethanol provides evidence for the assignment of the relative stereochemistry at C-16 in (— )-isoelaeocarpiline [4, 5, 9). 

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