1,3-dibromo-5,5-dimethylhydantoin
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| Surname | 1,3-dibromo-5,5-dimethylhydantoin | ||||||||||||||||||
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| Molecular formula | C 5 H 6 Br 2 N 2 O 2 | ||||||||||||||||||
| Brief description |
white powder or crystals |
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| properties | |||||||||||||||||||
| Molar mass | 285.92 g mol −1 | ||||||||||||||||||
| Physical state |
firmly |
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| density |
2.183 g / cm 3 |
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| Melting point |
197-199 ° C |
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| solubility |
slightly soluble in acetone , THF and 1,4-dioxane |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | |||||||||||||||||||
1,3-Dibromo-5,5-dimethylhydantoin ( DBDMH for short ) is a heterocyclic organic compound that is used in organic synthesis as a bromination reagent .
Extraction and presentation
1,3-Dibromo-5,5-dimethylhydantoin is produced by reacting bromine with 5,5-dimethylhydantoin in the presence of sodium hydroxide solution . The starting material 5,5-dimethylhydantoin can be synthesized commercially very easily from potassium cyanate , ammonium carbonate and acetone .
properties
Physical Properties
1,3-Dibromo-5,5-dimethylhydantoin forms a white powder or white crystals which melt at 197–199 ° C with decomposition. The compound crystallizes in a rhombic crystal lattice.
Chemical properties
1,3-Dibromo-5,5-dimethylhydrandoin is not stable in all solvents. Thus, it reacts with dimethylformamide or dimethylacetamide strongly exothermic with heat of reaction from -265 kJ · mol -1 and -240 kJ · mol -1 . Solutions in tetrahydrofuran are already unstable at 20 ° C and should be used at temperatures below 8 ° C. Hydrolysis to dimethylhydantoin and hypobromous acid or hypobromite takes place in water or sodium hydroxide solution .
use
1,3-Dibromo-5,5-dimethylhydrandoin is used in organic synthesis as a bromination reagent. A common application is the radical bromination of benzylic aromatics and heterocycles. The simplest reaction here would be the conversion of toluene to benzyl bromide . The advantage of this bromination variant is that it can also use acid-sensitive starting materials. Electrophilic bromination of alkenes results in bromohydrins, which can be further converted to the corresponding epoxides. In the presence of fluorinating agents such as hydrogen fluoride , pyridine-hydrogen fluoride complex or silicon tetrafluoride , bromine and fluorine are added to a double bond. With alkynes in the presence of pyridine-hydrogen fluoride complex ( E ) -bromofluoroalkenes are obtained with a high stereoselectivity.
The use of the compound can be seen as an economical alternative to N-bromosuccinimide because of its lower price and higher bromine content .
It is as Bromlieferant in bleach and disinfectants used.
Individual evidence
- ↑ a b c d e f g h e-EROS Encyclopedia of Reagents for Organic Synthesis , 1999-2013, John Wiley and Sons, Inc., entry for 1,3-dibromo-5,5-dimethylhydantoin, accessed May 19 2016 .
- ↑ a b Technical Evaluation Report 1,3-Dibromo-5,5-dimethylhydantoin (DBDMH) Handling / Processing compiled by ICF International for the USDA National Organic Program, July 17, 2012, pdf .
- ↑ a b data sheet 1,3-dibromo-5,5-dimethylhydantoin from Sigma-Aldrich , accessed on December 7, 2017 ( PDF ).
- ↑ Kruszynski, R .: Short intermolecular N-Br ... O = C contacts in 1,3-dibromo-5,5-dimethylimidazolidine-2,4-dione in Acta Cryst. C63 (2007) o389-o391, doi : 10.1107 / S0108270107013868 .
- ↑ Shimizu, S .; Imamura, Y .; Ueki, T .: Incompatibilities between N-Bromosuccinimide and Solvents in Org. Process Res. Dev. 18 (2014) 354-358, doi : 10.1021 / op400360k .
- ↑ Gries, J .; Krüger, J .: A Practical Approach to N - (Trifluoroacetyl) sulfilimines in Synlett 25 (2014) 1831-1834, doi : 10.1055 / s-0034-1378328 .
- ↑ Radhakrishnan, K .; Indrasenan, P .: in J. Indian Chem. Soc. 62 (1985) 84-86.
- ↑ a b Entry on 1,3-dibromo-5,5-dimethylhydantoin. In: Römpp Online . Georg Thieme Verlag, accessed on December 19, 2017.