Sodium Hydroxide → 1-Bromo-3-chloro-2,2,5,5-tetramethylimidazolidin-4-one

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Reaction Steps

6.4 Grams (0.045 mole) of 2,2,5,5-tetramethylimidazolidin-4-one prepared as in example 2 was dissolved in 55 milliliters of 1 Normal sodium hydroxide solution (0.055 mole) in a 250 milliliter flask. While maintaining the reaction mixture at a temperature of 5°-10° C. by use of an ice bath and stirring, 4.0 grams (0.025 mole) of liquid bromine was added dropwise. The reaction mixture was stirred at ice bath temperature for an additional 1 hour and then for 1-2 hours at cold water bath conditions (10°-20° C.). Following cooling the mixture below 10° C. again, 50 milliliters of 1 Normal sodium hydroxide solution (0.05 mole) was added, and chlorine gas was bubbled in while stirring at 5°-10° C. until the pH reached 6-7. The 1-bromo-3-chloro-2,2,5,5-tetramethylimidazolidin-4-one product precipitated as a white solid. The product was recovered by suction filtration and purified by recrystallization from hexane. The product yield was 11.2 grams or 97% of that theoretically expected. Elemental analysis of the product gave the following results: (calculated/found) % carbon 32.88/32.68, % hydrogen 4.70/4.74, % nitrogen 10.96/10.83, % bromine 31.31/33.37, % chlorine 13.89/12.67. The rather high and low found values as compared to the theoretical values for bromine and chlorine, respectively, indicate that the product was contaminated with a small amount of 1,3-dibromo-2,2,5,5-tetramethylimidazolidin-4-one. The product was found to have a solubility in water ranging from 0.102 grams in 100 milliliters of water at 3° C. to 0.193 grams in 100 milliliters of water at 37° C. The product had a melting point of 88° C.±2° C. Analysis of the product by proton NMR and infrared spectroscopy yielded the following results: 1H NMR (CCl4) δ=1.34 (S,6H), δ =1.50 (S,6H); IR (KBr) 1700, 2950 cm-1.

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