Bipyrrole bipyrrolic

ANTIBIOTICS - NUCLEOSIDES AND NUCLEOTIDES] (Vol 3) 5-(2H-Pyrrol-2-ylidenemethyl)-2,2y-bipyrrole [22187-69-5]... 

An example of dimerization involving a-protonation is provided by the formation of the 2,2 -bipyrrole (44) on treatment of 3,4-dimethylpyrrole with 6N HCl (68JCS(C)2527). The... 

Bipyrimidin-4(3H)-one, 2 -(dimethylamino)-6-hydroxy-synthesis, 3, 114 l,r Bipyrrole, octaphenyl-photochromic compound, 1, 386 Bipyrroles... 

The reaction of 2,2 -bipyrrole with orthoformic acid triethyl ester in the presence of phosphoryl chloride (POCI3) produced a compound which gave the H NMR spectrum 5. Which compound has been prepared ... 

Schemes based on the acid-catalyzed condensation of a bipyrrole with a dipyrrylmethane are in general unsuccessful for the synthesis of corroles. Thus, the bipyrroles 1 fail to give corroles when reacted with the appropriate dipyrrylmethane 2.10,11 However, cobalt(III) corrole 3 can be prepared in moderate yield by a [2 + 2] approach involving bipyrrole T and dipyrrylmethane 2 bearing formyl groups and carboxylic groups, respectively, and heating initial condensation products, presumably norbilenes, with cobalt(II) acetate and triphenylphosphane in methanol.12...

This rational approach for the synthesis of isocorroles is complemented by observations discovered in investigations on porphycencs. Firstly as minor side products of the McMurry coupling of 2,2 -bipyrroles-5,5 -dicarbaldehydes, e.g. 3, isocorroles arc formed, e.g. 5.2... 

The synthesis is straightforward because for the preparation of the tetrapyrranc a bipyrrole can also be used as a central unit to which a benzyl 5-(acetoxymethyl)pyrrole-2-carboxylate can be attached as the terminal pyrrole rings. Debenzylation by catalytic hydrogenation then gives the desired tetrapyrrane building block 68. 

Two type la syntheses of (3-hydroxypyrroles have appeared. An aza-Nazarov cyclization of l-azapenta-l,4-dien-3-ones produced (3-hydroxypyrroles including 2,2 -bipyrroles <06EJO5339>. A second approach to a (3-hydroxypyrrole involved an intramolecular N-H insertion into a rhodium carbene derived from the decomposition of a diazoketone <06JOC5560>. On the other hand, the photochemical decomposition of the diazoketone led to pyrrolidin-2-ones. 

A Sml2-induced reductive cyclization of (V-(alkylketo)pyrroles provided an entry into medium ring 1,2-annelated pyrroles <06EJO4989>. An oxidative radical alkylation of pyrroles with xanthates promoted by triethylborane provided access to a-(pyrrol-2-yl)carboxylic acid derivatives <06TL2517>. An oxidative coupling of pyrroles promoted by a hypervalent iodine(III) reagent provided bipyrroles directly <060L2007>. 

The pyrrole ring is widely distributed in nature. It occurs in both terrestrial and marine plants and animals [1-3]. Examples of simple pyrroles include the Pseudomonas metabolite pyrrolnitrin, a recently discovered seabird hexahalogenated bipyrrole [4], and an ant trail pheromone. An illustration of the abundant complex natural pyrroles is konbu acidin A, a sponge metabolite that inhibits cyclin-dependent kinase 4. The enormous reactivity of pyrrole in electrophilic substitution reactions explains the occurrence of more than 100 naturally occurring halogenated pyrroles [2, 3]. 

Although V-protected 2-lithiopyrroles are readily generated and many types are known [6, 26], these intermediates have not generally been employed to synthesize halogenated pyrroles. One exception is the synthesis of the two natural seabird hexahalogenated bipyrroles 15 and 17,... 

As expected, reaction of A-aroylpyrroles 28 in the absence of added arene affords the bipyrroles 29 or cyclized product 30 [32, 33], Bipyrrole 31 was prepared via this oxidative coupling reaction [32],... 

An efficient and novel route to 3,3-bipyrroles, such as 203, involves the oxidative-cyclization of cyclodiyne 202 [147],... 

Bipyrrole alkaloids, cyclic peptides, quinones, macrolides, polyethers Vertebrata Osteichthyest, 22,000 spp. 

S., Vatter, S., Chahbane, N., Lenoir, D., Schramm, K.W. and Scherer, G. (2005) Biological activity and physicochemical parameters of marine halogenated natural products 2,3,3, 4,4, 5,5 -heptachloro-l -methyl-1,2 -bipyrrole and 2,4,6-tribromoanisole. Archives of Environmental Contamination and Toxicology, 48, 1-9. 

Fig. 1 Building units of conducting polymers, (1) polyacetylene (PA) (2) polypyrrole (PPy), polythiophene (PTh), polyfurane (PFu) (3) polyphenylene (PP) (4) polyaniline (PANI) 5 polyindole (PIND) (6) polycarbazole (PCaz) (7) polyazulene (Paz) (8) polynaphthalene (PNa) (9) polyanthracene (PAnth) (10) polypyrene (PPyr) (11) polyfluorene (PFiu) (12) poly(isothionaphthalene) (PITN) (13) poly(dithienothiophene) (14) poly(thienopyrrole) (15) poly(dithienylbenzene) (1G) poly(3-alkylthiophene) (17) poly(phenylene vinylene) (18) poly(bipyrrole) (PBPy), poly(bithiophene) (PBT) (19) poly(phenylenesulfide) (20) 4-poly(thienothiophene) (21) poly(thienyl vinylene), poly(furane vinylene) (22) poly(ethylenedioxythiophene) (PEDOT).

Therefore, the reactivity of these cationic species, similar to that of all other 3,3 substituted bithiophenes or bipyrroles, is low, probably resulting in a rate constant for the dimerization of < 10 M s [33d]. The tetrameric products of the subsequent coupling are even more stable than the dimers, which means that the polymerization process stops at this level, or becomes very slow. This reaction pattern is shown in Fig. 2, where the resulting species of... 

Surprisingly, many halogenated compoimds thought to be structurally similar to pollutants have been foimd to be naturally bioaccumulating in marine fish, birds, and mammals. These include the highly brominated bipyrroles (Figure 22.29). They are likely bacterial metabolites that are being passed up the food chain. 

Halogenated bipyrroles bioaccumulated in the marine food web. Source From Teuton, E. L., et al. 

There is a case where the resnlts of the electrode and chemical oxidation coincide (see Scheme 2.20). Calix[8]pyrrole was prepared from 3,3, 4,4 -tetraethyl-2,2 -bipyrrole during oxidative electrolysis in dichloromethane nsing platinum anode, tetrabutylammonium hydrogen sulfate as the... 

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