反应详情

The 5-chloro-5-(dichloromethyl)-4-ethyl-4-methyl-2-trifluoromethyloxazoline hydrochloride prepared in the preceding step was dissolved in 1800 mL of methanol, 72 mL of water, and 190 mL of concentrated hydrochloric acid, warmed to 50° C., and stirred at that temperature overnight. The crude reaction mixture was cooled and poured into an ice/water/ethyl ether mixture. The phases were separated and the ether layer was extracted once with water. The ether was saved (organic I). The combined aqueous layers were washed once with ethyl ether, and the organic layer was combined with organic I (organic II). The aqueous layer was neutralized with saturated aqueous sodium bicarbonate and extracted twice with ethyl ether. The combined ether layers were washed with water, brine, dried over anhydrous magnesium sulfate, treated with activated charcoal, and filtered through Celite™. To the resulting colorless solution was bubbled in anhydrous hydrogen chloride keeping the temperature below 20° C. The resulting white solid was filtered and dried yielding 124.8 g of the expected 3-amino-1,1-dichloro-3-methyl-2-pentanone hydrochloride as a white solid. The ethyl ether filtrate was combined with organic II and concentrated in vacuo; the resulting residue (150 g) was taken in a mixture of methanol/water/concentrated hydrochloric acid and heated at 50° C. over the weekend. The previously described workup yielded another 51 g of 3-amino-1,1-dichloro-3-methyl-2-pentanone hydrochloride. The total amount obtained was 175.8 g (61% yield).

1. customThe crude reaction mixture
2. temperaturewas cooled
3. customThe phases were separated
4. extractionthe ether layer was extracted once with water
5. washThe combined aqueous layers were washed once with ethyl ether
6. extractionextracted twice with ethyl ether
7. washThe combined ether layers were washed with water, brine
8. dry with materialdried over anhydrous magnesium sulfate
9. additiontreated with activated charcoal
10. filtrationfiltered through Celite™
11. customTo the resulting colorless solution was bubbled in anhydrous hydrogen chloride keeping the temperature below 20° C
12. filtrationThe resulting white solid was filtered
13. customdried