Indoles carbazoles

Tetrahydroquinoline Tetrahydro-iso-quinoline Indole Carbazole Piperazine... 

The fourth chapter of this volume comprises the second part of an ongoing series by Professor A. P. Sadimenko (Fort Hare University, South Africa) dealing with organometallic compounds of pyrrole, indole, carbazole, phospholes, siloles, and boroles. This follows the review in Volume 78 of Advances covering organometallic compounds of thiophene and furan. The enormous recent advances in this area are summarized and classified according to the nature of the heterocycle and of the metals. 

Pyrroles, indoles, carbazoles, phospholes, siloles and boroles in... 

Malbrancheamide (60) represents a novel type of CaM inhibitors although other natural indole alkaloids such as the unusual indole-carbazole alkaloids from a culture broth of a Nocardiopsis sp, namely K-252a-K252d, the brominated P-carbolines eudistomidins A and C, obtained... 

D. Pyrroles, Indoles. Carbazoles, and Pyrazoles Lithiation in an Al-Phenyl... 

Since tautomeric rearrangement is not possible when secondary amines react with acetylene, the intermediate enamines can be isolated.312,314 Vinylation with acetylene of heterocyclic nitrogen bases, such as pyrrole, indole, carbazole, was achieved in this way.312,315 However, when terminal alkynes react with secondary amines,... 

The TT-electron excess of the five-membered rings is accompanied by a high rr-donor character. The best measure of rr-donation is the value of first ionization potential, IP, which for all aromatic heterocycles with one heteroatom of pyrrole type reflects the energy of highest occupied rr-orbital. IP, values decrease in the sequence pyrrole > indole > carbazole furan > benzo[/ ]furan > dibenzofuran thiophene > benzo[/ ]thiophene (Section 2.3.3.9, Tables 21 and 23). Thus, the more extensive the rr-system, the stronger is its electron donor ability. Furan and thiophene possess almost equal rr-donation, which is considerably lower than that of pyrrole. 

Table 19 14N Chemical Shifts for Pyrrole, Indole, Carbazole and JV-Methyl Analogues ...

A. Simple indoles, carbazoles, carbolines, and physostygmine type alkaloids 106... 

Compounds of Pyrrole, Indole, Carbazole, Phospholes, Siloles, and Boroles,... 

V-Bromosuccinimide (NBS) supported on silica is a versatile reagent for controlled bromination of a variety of heterocyclic compounds. Indole, carbazole, benzimidazole,... 

By suitable substitution the enaminones can often serve as precursors for heterocycles and preparation of indoles, carbazoles, quinolines, acridines and phenaNthridines can be achieved easily. However, this part of enaminone chemistry can lead to surprising and unexpected reactions if the multifunctional properties of the enaminones are ignored, e.g. ring contraction, ring expansion and other rearrangements are observed. In some cases jft-ketoenamines react as the ene-component in cycloaddition. Enaminones are even suitable synthones for building aromatic rings. 

Of the more than 4500 known naturally occurring organohalogen compounds, a large fraction are alkaloids [1,3]. Most of these halogenated pyrroles, indoles, carbazoles, carbolines, tyrosines, and others have a marine origin. The present chapter surveys the occurrence, structure, and biosynthesis of these fascinating natural products. However, given their sheer number, this review focuses mainly on recent examples. 

Vinylation of various azoles (pyrrole, indole, carbazole, and their derivatives) with vinyl bromides catalyzed by palladium/phosphine complexes results in the A -vinylazoles in 30-99% yields (Equation 49) <20020L623>. This reaction with cis- and /ra r-P-bromostyrenes is stereospecific giving the respective products with full retention of configuration. 

The number of new natural products containing pyrroles and their benzo derivatives has increased considerably during the past decade. Due to space restrictions, only the most representative examples are included, and these witness the variety of structures and biological functions of natural products containing pyrroles, indoles, carbazoles, and related skeletons. 

Ionic hydrogenation is also described for indole, carbazole and furan derivatives (79MI1). However, it is most important for thiophenes since the latter are well known as poisons for most hydrogenation catalysts. 

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