Pyrrolocarbazoles

Although much less so than pyrrole polymers, indole polymers are beginning to be synthesized and studied as new materials. Electropolymerized films of indole-5-carboxylic acid are well-suited for the fabrication of micro pH sensors and they have been used to measure ascorbate and NADH levels. The three novel pyrroloindoles shown have been electrochemically polymerized, and the polymeric pyrrolocarbazole has similar physical properties to polyaniline. 

Regioselective bromination of the pyrrolocarbazole 1157 with NBS led to the bromocarbazole 1158, which, on halogen-metal exchange with butyllithium and... 

A photochemical approach has been used for the formation of the pyrrolocarbazole core of the telomerase inhibitor dictyodendrin B (Equation 81) <2005JA11620>, for the central core of furostifoline <2002CPB143> and for the synthesis of 7-azaindolocarbazoles <2002T6621>. 

The enaminone 119 (Z = COOEt) obtained from 18a/19a or 20 and ethyl /1-alanate on reaction with 3-indolylacetyl chloride and its /V-methyl derivative gave enamides 122 (R = H, Me), which on TiCl4-induced cyclization gave corresponding pyrrolocarbazoles 123 (R = H, Me). The base-induced transformations of these tetracycles to corresponding pentacyclic systems could not be achieved (91T4165). 

Allylation and benzylation continue to be exploited in a variety of situations. Indole undergoes a clay-catalyzed reaction with the acetoxymethylpyrrole (56) to give the pyrrolocarbazole (57). The reaction is not general and small yields of a variety of related products are obtained with substituted indoles (Equation (14)) <94JCS(Pl)i765>. 

The carbazole polymer poly(iV-vinylcarbazole) functions as a positive electrode material for a secondary lithium battery <85CC553>, and as a memory photoreceptor <91M1 204-0l>. The related poly[3-(3-bromocarbazol-9-yl)propyl]methylsiloxane (18) forms novel electrochromic films <89CC196>. Carbazole anions have b n used to initiate the polymerization of acrylates and methacrylates <95CC275>. The novel polymeric pyrrolocarbazole (19) displays physical properties similar to those of polyanilines. 

Application of Diels-Alder Reactions with 3-Vinyttndoles in the Synthesis of Indolocarbazoles and Pyrrolocarbazoles... 

McCort G, Duclos O et al (1999) A versatile new synthesis of 4-aryl- and heteroaryl-[3,4-c] pyrrolocarbazoles by [4+2] cycloaddition followed by palladium catalyzed cross coupling. Tetrahedron Lett 40 6211-6215... 

Poly (ADP-ribose) polymerase 1 (PARP-1) is a nuclear enzyme that catalyses the synthesis of poly (ADP-ribose) chains from NAD+ as part of the DNA repair process. Inhibitors of PARP have therapeutic utility in oncology through potentiation of the anti-tumor activity of radiation or DNA damaging chemotherapeutic agents. Previously we reported pyrrolocarbazole 1 as potent PARP-1 inhibitor (IC50 = 36 nM). Structural modifications around 1 to improve enzyme and cell potency led to the synthesis of a lead series of 4-substituted analogs 2. The synthesis and SAR of this series will be reported. 

The most complex bis-indolic derivatives may be the sulfated pyrrolocarbazoles isolated from Dictyodendrilla sp. harvested in Japan. These highly branched derivatives, which are unnamed, are inhibitors of aldose reductase (Sato et al, 1993). 

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