Synthesis 2008(5): 699-706  
DOI: 10.1055/s-2008-1032187
PAPER
© Georg Thieme Verlag Stuttgart · New York

Synthesis of Dinitro-Substituted Furans, Thiophenes, and Azoles

Alan R. Katritzky*a, Anatoliy V. Vakulenkoa, Jothilingam Sivapackiama, Bogdan Draghicia, Reddy Damavarapub
a Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA
Fax: +1(352)3929199; e-Mail: katritzky@chem.ufl.edu.;
b US Army ARDEC, Picatinny Arsenal, NJ 07806-5000, USA
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Publikationsverlauf

Received 27 September 2007
Publikationsdatum:
18. Februar 2008 (online)

Abstract

Direct nitration of the corresponding mononitro furans with fuming nitric acid, thiophenes with acetyl nitrate, and thiazoles with trifluoroacetyl nitrate, gave dinitro-substituted furans, thiophenes, and thiazoles. The nitrations of 2-alkylthiophenes with 3 and 5 molar equivalents of acetyl nitrate, generated in situ, are discussed. Reactions of the mononitro furans with fuming nitric acid gave 1,1,5,5-tetrasubstituted dihydrofurans as by-products. Treatment of 5-methyl-4-nitroisoxazole with hydrazine or its methyl or phenyl derivative, followed by oxidation of the corresponding 4-amino-5-nitro-1H-pyrazoles with hydrogen peroxide (50%) gave 4,5-dinitro-1H-pyrazoles. A safe one-pot synthesis of 1-alkyl-3,5-dinitro-1H-[1,2,4]triazoles was developed from dicyandiamide.