反应详情

The resultant compound of example 4 was converted to 1,3,3-trinitroazetidine as follows. To 1-tertiarybutyl-3,3-dinitroazetidine (20 g, 0.099 mole) in 25 ml of chloroform was added benzyl chloroformate (9.24 g, 0.054 mole). The mixture was stirred under reflux for 24 hours during which time isobutylene was generated and a white precipitate was formed. The mixture was allowed to cool and was the precipitate was separated by filtration. The filter cake was washed with methylene chloride, air dried and weighed to yield 6.4 g (27%) of 1-tertiarybutyl-3,3-dinitroazetidine hydrochloride. The filtrate was evaporated under vacuum to yield a yellow solid. This solid was taken up in warm toluene, the mixture filtered while hot, and the filtrate treated with hexanes to crystallize the product. The resultant product was collected by filtration and dried to yield 7.3 g (26%) of pure 1-(benzyloxycarbonyl)-3,3-dinitroazetidine as determined by 1H-nmr. The 1-(benzyloxycarbonyl)-3,3-dinitroazetidine (4.0 g, 0.014 mole) was dissolved in 40 ml of methylene chloride containing anisole (4.62 g, 0.04 mole) and to this admixture was added trifluoromethanesulfonic acid (10 g, 0.067 mole), slowly with vigorous stirring at room temperature. Carbon dioxide was evolved and the solution turned red in color. Stirring was continued for about 30 minutes after the addition. Diethyl ether was added slowly to quench the reaction and precipitate the resultant product. The solids were filtered, washed with diethyl ether and air-dried to yield 4.10 g (97%) of pure 3,3-dinitroazetidinium trifluoromethanesulfonate as determined by 1H-nmr. The 3,3-dinitroazetidinium trifluoromethanesulfonate (2.0 g, 0.0067 mole) was dissolved in 20 ml of water and neutralized with sodium bicarbonate (0.62 g, 0.0074 mole). The free base was extracted into chloroform (3×5 ml) and dried over sodium sulfate. The chloroform was removed under vacuum to quantitatively yield the resultant product, 3,3-dinitroazetidine (0.98 g) as a colorless oil. The 3,3-dinitroazetidinium trifluoromethanesulfonate (5.566 g) was dissolved in 50 ml of methanol and mixed with ammonium nitrate (1.5 g) in 20 ml of methanol. After about 1 minute, a precipitate began to form. The suspension was cooled and filtered to yield 2.6 g of the resultant product, 3,3-dinitroazetidinium nitrate (0.98 g). The 3,3-dinitroazetidinium nitrate was added to a mixture of acetic anhydride (1.50 g, 14.7 mmol), 0.030 g of 90% nitric acid and 0.026 g of anhydrous zinc chloride. The resultant thick slurry was heated at 40° C. thereat yielding a resultant solution. The solution was allowed to cool to room temperature, drowned with water, and allowed to crystallize. The resultant product was filtered, washed with water and dried to yield 0.87 g of pure 1,3,3-trinitroazetidine. This material was spectrally identical to a sample of 1,3,3-trinitroazetidine prepared according to Archibald et al., J. Org. Chem., 55, 2920 (1990).

1. customa white precipitate was formed
2. temperatureto cool
3. customwas separated by filtration
4. washThe filter cake was washed with methylene chloride, air
5. customdried