Guanidine-derived alkaloids

A novel polycyclic guanidine alkaloid, ptilomycalin A (51), was isolated from a red sponge, Hemimycale sp., from the Red Sea (Kashman et al. 1989). The authors report using long-range connectivity information gleaned from both COLOC and HMBC spectra in the elucidation of the structure. Some of the correlations observed in the HMBC spectrum were reported in the paper and are shown on the structure. 

Undoubtedly, even more interesting applications of inverse-detected methods are possible and will be developed as structural problems drive the spectroscopist to find new solutions. Some of the applications that have been presented herein have yet to be applied to an alkaloid. It is, however, only a question of an alkaloid structural problem amenable to solution by a particular technique and an investigator who is aware that the technique exists before corresponding applications in alkaloid chemistry appear. Finally, the recent availability of microinverse and microdual probes (Crouch and Martin 1992a,b) also promises to lead to applications of inverse-detected techniques in the elucidation of the structures of minor alkaloidal constituents that have, until now, been available in quantities too small to allow their structures to be elucidated. 

Ablordeppy SY, Hufford CD, Bourne RF, Dwuma-Badu D (1990) Proton NMR and carbon-13 NMR assignments of cryptolepine, a 3 4-benzo-d-carboline derivative isolated from Cryptolepis sanguinolenta. Planta Med 56 416-417 Alam M, Mroue M (1991) Crooksiine, a bisindole alkaloid from Haplophyton crooksii. Phytochemistry 30 1741-1744 

Atta-ur-Rahman, Nighat F, Nelofer A, Zaman K, Choudhary MI, DeSilva KTD (1991) Macroxine - a novel oxindole alkaloid from Alstonia macrophylla. Tetrahedron 47 3129-3136 

Bax A (1983a) Two-dimensional heteronuclear relayed coherence transfer spectroscopy. J Magn Reson 53 149-153 

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Asymmetric transfer hydrogenation was used as a key step in the synthesis of guanidine-derived alkaloid (+)-crispine E, a constituent of a basic fraction obtained from Carduus crispus The reaction was com-... 

Gramme 37, 113, 146, 175, 179 Graveoline 114 Guanidine alkaloids 57 Guanine derived alkaloids 49 Guaranine 43, 51 Guvacoline 86... 

Didemnum rodriguesi from New Caledonia contained the unusual peptidyl alkaloid caledonin (76), that formed a complex with Zn2+ and Cu+ ions between thiol and primary amine groups [100], The minalemines D-F (77-79) are peptide guanidine derivatives isolated from a Caribbean collection of D. rodriguesi and contain a sulfamic acid group [101]. The stereochemistry of cyclodidemniserinol trisulfate (80) from a Palauan specimen of Didemnum guttatum was partially determined [102]. 

Two alkaloids which form explosive salts have been identified as the guanidine derivatives pterogynine (28) and pterogynidine (29). The latter compound is believed to be identical to a guanidine alkaloid isolated from Alchornea javensis The structure of pterogynine (28) was confirmed by synthesis. ... 

The excellent reviews of Berlinck [1-5] have surveyed a great number of guanidine-type natural products. In addition, some guanidine-derived marine alkaloids have been reviewed by Kobayashi and Ishibashi [6,7]. Also, a recent book gave accounts of marine alkaloids including the phakellins, palau amines and oroidin-like dimers derived from bromopyrroles and polyketide-derived polycyclic guanidine alkaloids [8]. 

Assmann et al. described, in addition to known alkaloids, the isolation of the first pyrrole-imidazole alkaloid with a guanidine function instead of the aminoimidazole (127) [152] from the sponge Agdas wiedenmayeri, while its decarboxylated derivate laughine (128) was isolated from the sponge Eurypon laughlini [153],... 

Various unclassified alkaloids (aniline and anthranilic acid derivatives, cinnamic acid amides, guanidine bases, and oxazoles) are briefly reviewed in a general text on alkaloids.30... 

Asymmetric cyanohydrin synthesis remains an important reaction for organocatalysis and many of the catalyst classes discussed in subsequent chapters give highly effective catalysts for this reaction. These include Cinchona alkaloid derivatives, thioureas, guanidines, amine-oxides, diols and diamines. 

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