%0 Journal Article
%T Synthesis and Reactions of Furo[2,3-b]pyrroles
%A A. Krutosikov¨˘
%A C. A. Ramsden
%A M. Dand¨˘rov¨˘
%A A. Lycka
%J Molecules
%D 1997
%I MDPI AG
%R 10.3390/20400069
%X 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.
%K Methyl furo[2
%K 3-b]pyrrole-5-carboxylates
%K methyl 2-formylfuro[2
%K 3-b]pyrrole-5-carboxylates
%K methyl 2-cyanofuro[2
%K 3-b]pyrrole-5-carboxylates
%K methyl 2-(5'-tetrazolyl)furo[2
%K 3-b]pyrrole-5-carboxylates
%K 5- methoxycarbonylfuro[2
%K 3-b]pyrrole-2-carbaldehydes N
%K N-dimethylhydrazones
%U http://www.mdpi.com/1420-3049/2/4/69