- N-silylation of 2,4,6-trialkyl-2,4,6,8-tetraazabicyclo-|3.3.0|octane-3,7-diones
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N-Trimethylsilyl derivatives of 2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-diones have been prepared for the first time and the electrophilic substitution reaction of the trimethylsilyl group has been studied.
- Chegaev,Kravchenko,Lebedev,Strelenko,Belyakov
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- Synthesis of glycolurils and hydantoins by reaction of urea and 1, 2-dicarbonyl compounds using etidronic acid as a “green catalyst”
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Most of the known methods for the synthesis of heterocyclic compounds have disadvantages, such as a long reaction time and aggressive conditions. We have developed a new, rather simple and efficient method for the synthesis of a number of glycoluryls and hydantoins in water using a etidronic acid (HEDP) as “Green catalyst.” So, for the first time, the condensation reaction of ureas with 1, 2-dicarbonyl compounds was carried out in the presence of HEDP. Also based on NMR studies, a chemism of these reactions, which is stepwise, is proposed. It has been established that the optimal conditions for the synthesis of glycoluryls and hydantoins using HEDP are: temperature 80°C-90°C, 40-20 minutes, and the ratio of urea and HEDP is 1:1. In all cases, the remaining aqueous filtrate containing HEDP after the reaction can be reused for other cycles synthesis of glycoluril and other compounds, because HEDP is not converted during the reaction.
- Bakibaev, Abdigali A.,Uhov, Artur,S. Malkov, Victor,Yu. Panshina, Svetlana
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p. 4262 - 4270
(2020/10/02)
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- New Synthesis of 2,4,6,8-Tetramethyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione Using Etidronic Acid as a “Green” Catalyst
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Abstract: A new method has been developed for the synthesis of2,4,6,8-tetramethyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione in 62% yieldusing etidronic acid [1-hydroxyethane-1,1-diylbis(phosphonic acid), HEDP] as a“green” catalyst. A plausible stepwise mechanism of the reaction has beenproposed and partially confirmed by NMR data and studying model processes. Theeffects of the reaction medium and HEDP on particular species involved in thereaction, namely N,N′-dimethylurea, 4,5-dihydroxy-1,3-dimethylimidazolidin-2-one,and 2,4,6,8-tetramethyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione, havebeen studied by 1H and 13CNMR spectroscopy in D2O, neutral and acidified solutions(acetic acid-d4), andsolutions containing 1 equiv of HEDP.
- Panshina, S. Yu.,Ponomarenko,Bakibaev,Malkov
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p. 2067 - 2073
(2021/02/09)
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