Pyrrole 3 - acetyl - 1 - benzyl - 2 - methyl 5 -

Following formation of the S-Me derivative of ethyl 4-(1-benzyl-2-thia-oxopyrrolidin-3-yl)-5-(1,3-dioxobutyl)pyrrole-2-carboxylatewith methyl ir ide,the mixture was heated in a sealed Pyrex tube under nitrogen at SOX for 15 hours to produce ethyl 5-acetyl-6-benzyl-4-hydroxy-3,6,7,8-tetra-hydrobenzo-[1,2-b 4,3-b ]dipyrrole-2-carboxylate in 97% yield (ref.27)... 

Padwa et al. (75) found that the unsymmetrical miinchnone 137, which was generated from A-acetyl-7/-benzylglycine (136) and refluxing acetic anhydride, reacts with methyl propiolate to give an 8 1 mixture of pyrroles 138 and 139. The same product ratio is obtained from the reaction of methyl propiolate and the azomethine ylide derived from 7/-benzyl-A(-(a-cyanoethyl)-A(-[(trimethylsilyl)-methyl] amine. 

Phase-transfer catalysis was found <1996CHEC-II(7)1> to be successful for N-substitution of the furo[3,2-/ ]pyrrole system. The reaction of 81a with methyl iodide or benzyl chloride gave 81b and 81c derivatives. Methyl 4-acetyl-2-[3-(trifluoromethyl)phenyl]furo[3,2-3]pyrrole-5-carboxylate 82 was obtained by reacting 81a in boiling acetic anhydride (Scheme 6) <2005CEC311>. 

The acetyl group of the 4-acetylfuro[3,2-6]pyrrole (8b) (see Table 6) readily undergoes hydrolysis and under conditions of phase transfer catalysis with methyl iodide or benzyl chloride gave the 4-methyl (8c) or 4-benzylfuro[3,2-6]pyrrole (8d) via the unstable 4//-furo[3,2-6]pyrrole (8) <92CCC1487>. 

Syntheses from Non-Carbohydrate Sources. The Birch reduction of an iV-protected 2-carboxymethyl substituted pyrrole and subsequent quench with an appropriate electrophile e.g. methyl 2,3,4-tri-0-benzyl-6-deoxy-6-iodo-a-D-glucopyranoside) affords a simple route to N-protected 2,2-disubstituted dihydropyrroles 81. These can be further elaborated into the corresponding 4-sub-stituted imino-ribitols 82 in good overall yield by a simple strategy of reduction, acetylation, syn-dihydroxylation and deprotection. ... 

A suspension of benzyl 2-acetoxymethyl-3-(2-methoxycarbonylethyl)-4-methyl-pyrrole-5-carboxylate and 3-acetyl-2,4-dimethylpyrrole in methanol treated with p-toluenesulfonic acid hydrate, and warmed 4 hrs. at 35 under Ng -> product. Y 91%. F. e., also tripyrranes, s. A. M. d A. Rodia Gonsalves, G. W. Kenner, and K. M. Smith, Tetrah. Let. 1972, 2203. 

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