Total syntheses of isonaamine C and isonaamidine E.

@article{Lima2011TotalSO,
  title={Total syntheses of isonaamine C and isonaamidine E.},
  author={H. Lima and Beatriz Garcia-Barboza and Nicole N Khatibi and C. J. Lovely},
  journal={Tetrahedron letters},
  year={2011},
  volume={52 44},
  pages={
          5725-5727
        }
}
The total syntheses of two alkaloids isolated from a marine sponge of the Leucetta sp. have been accomplished in 6 and 7 steps starting from a 4,5-diiodoimidazole derivative. Grignard mediated halogen-metal exchange was used to install the benzyl side chain. C2 substitution was accomplished via lithiation followed by quenching with trisyl azide which provided isonaamine C after hydrogenation. Isonaamidine E was then prepared from isonaamine C via introduction of the hydantoin ring by reaction… Expand
Total synthesis of 7'-desmethylkealiiquinone.
TLDR
The total synthesis of an analogue of the marine alkaloid kealiiquinone has been completed through application of an intramolecular Diels-Alder reaction of an imidazole-containing enyne via a reaction with glyoxal in the presence of KCN. Expand
Studies Towards the Leucetta-derived Alkaloids Spirocalcaridine A and B - Possible Biosynthetic Implications.
TLDR
Elaboration of the α-iodoenone via an Ullmann-like, copper-catalyzed amidation provided a formamide which upon treatment with methylamine undergoes a dienol-arene rearrangement, providing the corresponding kealiinine-like framework, suggesting a possible biosynthetic links between the spirocalcaridines and the naphthimidazole group of Leucetta alkaloids. Expand
Total synthesis and cytotoxicity of Leucetta alkaloids.
TLDR
The total synthesis of a number of representative natural products isolated from Leucetta and Clathrina sponges containing a polysubstituted 2-aminoimidazole are described, and for comparative purposes a series of naphthimodazole-containing family members are included. Expand
Development of a General Approach to the Leucetta-Derived Alkaloids
Abstract The Leucetta alkaloids are a group of marine sponge-derived secondary metabolites that contain a polysubstituted imidazole moiety. A general strategy toward this family of alkaloids has beenExpand
A facile protocol for the preparation of 5-alkylidene and 5-imino substituted hydantoins from N,N′-disubstituted parabanic acids
Abstract A convenient procedure for the preparation of various substituted (thio)hydantoins is described. The method is based on Wittig and aza-Wittig reactions of parabanic acids with phosphoniumExpand
Chapter 2 - Synthesis of Imidazole Alkaloids Originated in Marine Sponges
Abstract A number of secondary metabolites resembling a polysubstituted 2-aminoimidazole scaffold are found in a variety of marine sponges. Due to the diversity in the biological activity withExpand
Dearomatizing spirocyclization reactions of alkynyl cyanamides
Electrophile-induced dearomatizing spirocyclization reactions of propargylic cyanamides leading to cyclohexadienone derivatives are described. An unusual one-pot spirocyclization-N-cyanation reactionExpand
Tandem Oxidative Dearomatizing Spirocyclizations of Propargyl Guanidines and Ureas.
Treatment of propargyl ureas or guanidines with iodosobenzene diacetate results in an oxidative tandem amination/etherification dearomatizing spirocyclization. This transformation leads directly toExpand
Recent Advances in the Synthesis of Hydantoins: The State of the Art of a Valuable Scaffold.
TLDR
Novel synthetic routes to various hydantoin structures, the advances brought to the classical methods in the aim of producing more sustainable and environmentally friendly procedures for the preparation of these biomolecules, and a critical comparison of the different synthetic approaches developed in the last twelve years are described. Expand
Trifluoroacetic acid: Uses and recent applications in organic synthesis
Abstract Trifluoroacetic acid (TFA), discovered at the early 20th century, has been widely used in organic synthesis as a solvent, catalyst and reagent. Many chemical transformations should be doneExpand
...
1
2
...

References

SHOWING 1-10 OF 16 REFERENCES
Total Syntheses of Naamidine G and 14-Methoxynaamidine G.
Simple total syntheses of two Leucetta-derived marine alkaloids have been developed using position specific halogen-metal exchange of polyhaloimidazoles to introduce the benzyl substitutedExpand
Expedient total syntheses of preclathridine A and clathridine A
Abstract A short and operationally simple total synthesis of two Leucetta -derived marine alkaloids has been developed, which rely on position specific halogen–metal exchange to introduce theExpand
Structure and synthesis of 2-aminoimidazole alkaloids from Leucetta and Clathrina sponges.
TLDR
The isolation, structural determination and synthetic studies towards this growing class of natural products towards the Calcarea family of sponges are described. Expand
1-methyl-3-trimethylsilylparabanic acid as an effective reagent for the preparation of N-substituted (1-methyl-2,5-dioxo-1,2,5H-imidazolin-4-yl)-amines and its application to the total synthesis of isonaamidines A and C, antitumor imidazole alkaloids
1-Methyl-3-trimethylsilylparabanic acid (17) was successfully used in the final step of the total synthesis of isonaamidine A (9), isonaamidine C (11) and pyronaamidine (8), antitumor marineExpand
Total synthesis of (+/-)-calcaridine A and (+/-)-epi-calcaridine A.
TLDR
The first total synthesis of the Leucetta alkaloid calcaridine A is described based on a biosynthetic postulate using an oxidative rearrangement of a 4,5-disubstituted imidazole and an X-ray crystal structure determination on the latter has allowed the assignment of the relative configuration of the epimeric natural product and calaridine A by extrapolation. Expand
A concise total synthesis of naamidine A.
TLDR
Key benefits of the described pathway include its brevity, its synthetic ease, and its flexibility with respect to the preparation of analogues. Expand
Polyfunctionalisation of imidazole via sequential imidazolyl anion formation
Abstract A method for achieving the sequential functionalisation of the imidazole ring in the order C-5→C-4→C-2 is described. The chemistry proceeds via the regioselective formation of positionallyExpand
Lithiation of 1‐benzylimidazole. A hypothesis on the regioselectivity of the electrophilic attacks on the lithiated species
Sequential lithiations of 1-benzylimidazole, 1, and of 1-benzyl-1,2,4-triazole, 2, followed by treatment with electrophiles others than alkyl halides result in reactions at C-2. However, benzylExpand
Magnesium-Oppenauer oxidation of alcohols to aldehydes and ketones
Abstract Using a magnesium-Oppenauer oxidation aldehydes and ketones are prepared from halomagnesium alkoxides, which in turn are the products of Grignard reactions.
Uniquely modified imidazole alkaloids from a calcareous Leucetta sponge.
A Fijian collection of the calcareous sponge Leucetta sp. was investigated and yielded four new imidazole alkaloids. One compound, (+)-calcaridine A (6), is unique in its overall structure andExpand
...
1
2
...