Synthesis of 4,5-dihydroxy-1,3-dinitroimidazolidin-2-one

Abstract

A convenient method for the synthesis of 4,5 dihydroxy 1,3 dinitroimidazolidin 2 one from N,N´ dinitrourea is developed.Key words: 4,5 dihydroxy 1,3 dinitroimidazolidin 2 one, N,N´ dinitrourea, synthesis. N,N´ Dinitrourea (1, DNU) is a high energy com pound with high density (1.98 g cm -3 ) and low thermal stability. It can be used as a precursor of other high energy compounds with the DNU fragment, for example, di and tetranitroglycolurils. The following information for DNU has been reported: flash point 147-149 °С, decomposi tion temperature 138-148 °С, spontaneous ignition in air is possible at room temperature; 1 m.p. 107-110 °С (ethyl acetate); 2 fast decomposition at 120 °С (DSC), greater impact and friction sensitivity in comparison with hexo gen, 3 temperature of the onset of decomposition is 90 °С, and X ray data. 4 The use of the method 2 for the DNU synthesis (nitra tion of urea with a mixture of nitric and sulfuric acids followed by filtration and washing with dichloromethane), does not allow one to obtain pure DNU (the DNU sample contains up to 20% of sulfuric acid). The attempt to re produce the other method for the DNU synthesis (nitra tion of urea with a mixture of nitric and sulfuric acids followed by washing with trifluoroacetic acid) 3 resulted in a yield that was approximately 2.5 times lower (27%) than the yield reported 3 (67%) (a method for DNU synthesis analogous to the method mentioned 3 was also used in the other investigation, 4 the yield was 40%). All the described methods 2-4 are similar to each other in nitration time (1-3 h) and temperature (0-5 °С), but differ in the ureanitric-sulfuric acid mixture ratio, and also in relative amounts of nitric acid (relative to urea).We developed a method for the synthesis of DNU that allows one to obtain the product with properties that are well reproducible (some of them are described 5 ), and in relatively high yield (64%). Oleum (20%) was used instead of sulfuric acid in the proposed method. 4,5 Dihydroxy 1,3 dinitroimidazolidin 2 one (2) is the condensation product of dinitrourea with glyoxal, it has good oxygen balance and lower impact and friction sensitivity in comparison with DNU. This compound has two free positions (hydroxy groups) for further functional ization, therefore, it can be used as a building block for the introduction of 1,3 dinitroimidazolidin 2 one fragment into molecules of organic compounds. The method for its synthesis from DNU and glyoxal described in the litera ture 6 leads to low yields of the target compound (41.7%). Nitration of 4,5 dihydroxy 2 nitroiminoimidazoline gives compound 2 in 30% yield. 7The use of crude DNU (as obtained using the method described earlier 6 and containing up to 20% of sulfuric acid) might be one of the reasons of the low yield of 2 from DNU. We assumed that the use of pure DNU would posi tively affect the yield of the target product. Initial efforts of the synthesis of compound 2 from pure DNU and aque ous glyoxal were unsuccessful -the hydrolytic decompo sition of DNU has occurred (appare...

Synthesis, Structure, and Properties ofN,N′‐Dinitrourea

“…Dinitrourea II dissolution in aqueous glyoxal at a temperature below 40 8C leads to 1,3-dinitro-1,3-diaza-4,5-dihydroxycyclopentane-2-one (XX) [30]. The use of trifluoroacetic acid as the medium for this reaction contributed to an increase in the yield of compound XX up to 96 % [31].…”