caa a22 4500 378939246 CHVBK 20180305123648.0 cr unu---uuuuu 161128e20040930xx s 000 0 eng 10.1351/pac200476091691 doi (NATIONALLICENCE)gruyter-10.1351/pac200476091691 Monocyclic and cascade rearrangements of furoxans [Elektronische Daten] [N. N. Makhova, I. V. Ovchinnikov, A. S. Kulikov, S. I. Molotov, E. L. Baryshnikova] Monocyclic rearrangements of azoles are extensively studied as alternative methods for the preparation of new heterocyclic systems. The present work is devoted to investigation of monocyclic and cascade rearrangements of 1,2,5-oxadiazole 2-oxide (furoxan) derivatives. It was found during investigations that rearrangements of furoxan ring had some peculiarities in comparison with analogous rearrangements of other azoles. Therefore, three different kinds of rearrangements were found. The first of them occurred through a dinitroso-ethylene intermediate and resulted in the synthesis of 1,2,3-triazole 1-oxides [oximes of 5-acetyl-4-phenyl(methyl)-2-phenyl-2H -1,2,3-triazole 1-oxides and 2-(furoxan-4-yl)-4-nitro-5-R-2H -1,2,3-triazole 1-oxides ]by thermal recyclization accordingly of 3-methyl-4-acetyl(benzoyl)furoxans phenylhydrazones and 3,3'-(R)-disubstituted-4,4'-azofuroxans. The latter reaction was performed in an oxidizing medium. The second kind of rearrangement (classical variant) was the synthesis of new azoles containing the 1-nitroalkyl substituent. These rearrangements were performed using three examples: base-induced interconversion of furoxanyl ketone phenylhydrazones into 5-(1-nitroalkyl)-2H-1,2,3-triazole derivatives and of 1-alkyl(aryl)-3-(furoxan-4-yl)amidines into 1-substituted 3-(1-nitroalkyl)-1,2,4-triazoles as well as a thermally induced rearrangement of 4-thioureido-3-R-furoxans into derivatives of 5-amino-3-(1-nitroalkyl)-1,2,4-thiadiazole including (5-amino-1,2,4-thiadiazol-3-yl)nitro-formaldehyde arylhydrazones (where R =N=N -Ar). Rearrangements of the third kind were those of the cascade type. Three new cascade rearrangements of azofuroxan derivatives [3,3'-azo-4,4'-bis(acetylamino)furoxans, 3-arylazo-4-acetylaminofuroxans, and 3-arylazo-4-(3- ethoxycarbonylureido)furoxans] into 4-amino-5-nitro-2H-1,2,3-triazole derivatives were discovered. These three reactions were assumed to include two consecutive (cascade) rearrangements: a 1,2,4-oxadiazole ring was formed at the first step and then transformed into a 1,2,3-triazole ring with the participation of an azo group. © 2013 Walter de Gruyter GmbH, Berlin/Boston Makhova N. N. N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia aut Ovchinnikov I. V. N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia aut Kulikov A. S. N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia aut Molotov S. I. N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia aut Baryshnikova E. L. N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia aut Pure and Applied Chemistry De Gruyter 76/9(2004-09-30), 1691-1703 0033-4545 76:9<1691 2004 76 pac https://doi.org/10.1351/pac200476091691 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1351/pac200476091691 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Makhova N. N. N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia aut NATIONALLICENCE 700 1- Ovchinnikov I. V. N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia aut NATIONALLICENCE 700 1- Kulikov A. S. N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia aut NATIONALLICENCE 700 1- Molotov S. I. N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia aut NATIONALLICENCE 700 1- Baryshnikova E. L. N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia aut NATIONALLICENCE 773 0- Pure and Applied Chemistry De Gruyter 76/9(2004-09-30), 1691-1703 0033-4545 76:9<1691 2004 76 pac CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter