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Synthesis and Reactions of Furo[2,3-b]pyrroles
Department of Organic Chemistry, Faculty of Chemical Technology, Slovak Technical University, SK-812 37 Bratislava, Slovak Republic
Department of Chemistry, Keele University, Keele Staffordshire ST5 5BG, UK
Research Institute for Organic Syntheses, CZ-53218 Pardubice-Rybitví, Czech Republic
* Author to whom correspondence should be addressed.
Received: 27 December 1996; Accepted: 24 January 1997 / Published: 20 April 1997
Abstract: Methyl 6H-furo[2,3-b]pyrrole-5-carboxylate (2a) was prepared by thermolysis of the corresponding methyl 2-azido-3-(3-furyl)propenoate (1). 6-Methyl (2b) and 6-benzyl (2c) derivatives were obtained using phase-transfer catalysis conditions (PTC). The formylation of 2a-2c gave 2-formylated compounds (3a-3c). Compounds 4b, 4c were prepared by reactions of corresponding esters 2b, 2c with hydrazine in refluxing ethanol. By reaction of 3a-3c with hydroxylammonium chloride in acetic anhydride in the presence of pyridine, methyl 2-cyano-6-R1-furo[2,3-b]pyrrole-5-carboxylates (5a-5c) were obtained. The reaction of these compounds with sodium azide and ammonium chloride in dimethylformamide led to methyl 2-(5'-tetrazolyl)-6-R1-furo[2,3-b]pyrrole-5-carboxylates (6a-6c). A series of 5-methoxycarbonyl-6-R1-furo[2,3-b]pyrrole-2-carbaldehyde N,N-dimethylhydrazones (7a-7c) was prepared from methyl 2-formyl-6-R1-furo[2,3-b]pyrrole-5-carboxylates (3a-3c) and unsym-dimethylhydrazine. The correlation of the 13C and 15N chemical shifts with the data of the calculated (AM1) net atomic charges is discussed.
Keywords: Methyl furo[2; 3-b]pyrrole-5-carboxylates; methyl 2-formylfuro[2; 3-b]pyrrole-5-carboxylates; methyl 2-cyanofuro[2; 3-b]pyrrole-5-carboxylates; methyl 2-(5'-tetrazolyl)furo[2; 3-b]pyrrole-5-carboxylates; 5- methoxycarbonylfuro[2; 3-b]pyrrole-2-carbaldehydes N; N-dimethylhydrazones
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Krutosiková, A.; Ramsden, C.A.; Dandárová, M.; Lycka, A. Synthesis and Reactions of Furo[2,3-b]pyrroles. Molecules 1997, 2, 69-79.
Krutosiková A, Ramsden CA, Dandárová M, Lycka A. Synthesis and Reactions of Furo[2,3-b]pyrroles. Molecules. 1997; 2(4):69-79.
Krutosiková, A.; Ramsden, C. A.; Dandárová, M.; Lycka, A. 1997. "Synthesis and Reactions of Furo[2,3-b]pyrroles." Molecules 2, no. 4: 69-79.