Pyrrolylmagnesium bromide

Aryl-4,5-dihydropyridazin-3(2//)-ones react with pyrrolylmagnesium bromide to give 6-aryl-3(l-pyrrolyl)pyridazines or, when 1 4 molar amounts of reagents are used, a mixture of 6-aryl-3(l-pyrrolyl)pyridazines and 3,4-di(l-pyrrolyl)-4,5-dihydropyridazines (Scheme 54 (79RRC453). 

The first successful attempt to prepare bicyclic indolizinedione derivatives 210 was achieved by the reaction of dimethylmaleic anhydride with pyrrolylmagnesium bromide followed by the cyclization of the intermediate acid. The corresponding unsubstituted desmethyl compound cannot be prepared this way [90JCS(P1) 1463]. 

Palladium-catalyzed cross-coupling reactions are not restricted to stannane derivatives, however, and other azaheterocyclic carbanion derivatives to have been investigated include l-methyl-2-pyrrolylmagnesium bromide and l-methyl-2-pyrrolylzinc chloride (81TL5319), l-methyl-2-indolymagnesium bromide (81TL5319), l-substituted-2- and 5-imidazolyl-... 

Chloropyrroles have been prepared from organometallic derivatives indeed, the first synthesis of 2-chloropyrrole was from the reaction of pyrrolylmagnesium bromide with chlorine at -50°C [62MI2 77MU], and lithium derivatives with NCS have also been used (84MI3). 

An interesting reaction of tosyl azide with 2-methylindole and with 2-pyrrolylmagnesium bromide yields the 3-(3-indolyl)azoindole and the corresponding azopyrrole (B-70MI30500, B-77MI30502), possibly by a mechanism shown in Scheme 40. A similar reaction occurs between 2-methylindole and 2,4,6-trinitrophenyl azide. 

Pyrrole-2-carboxylic acid esters have been prepared from ethyl chloroformate and pyrrolylmagnesium bromide or pyrrolyllithium, by hydrolysis and decarboxylation of dimethyl pyrrole-1,2-dicarboxylate followed by re-esterification of the 2-acid and by oxidation of pyrrole-2-carboxaldehyde followed by esterification with diazomethane. ... 

It was prepared by alkylation of pyrrolylmagnesium bromide (Vitzthum and Werkhoff, 1976b). Shibamoto and Bernhard (1978) observed its formation from the reaction of L-rhamnose with ammonia. 

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