Sulfuric Acid → 3-Methyl-5-(1-methyl-2(S)-pyrrolidinyl)isoxazole

Temperature

70 °C

To the solution of the product from step 25c above was added 12 mL of conc H2SO4, and the mixture was warmed to 70° C. and stirred for 2 hr. The solution was cooled in an ice-water bath, and adjusted to pH 12 by slow addition of 50% aqueous NaOH (40 g). The mixture was extracted twice with ethyl acetate, and the combined extracts Were dried over Na2SO4. The solid were removed by filtration, and the filtrate was distilled, first at atmospheric pressure to remove the solvent and, finally, under vacuum to provide the title compound as a nearly colorless liquid (4.74 g, 57%). b.p. 115°-117° C./20 mm Hg. 1H NMR (CDCl3) δ: 1.8-2.1 (m, 3H), 2.32 (s, 3H), 2.21 (m, 1H), 2.29 (s, 3H), 2.36 (m, 1H), 3.17 (m, 1H), 3.53 (t, J=8 Hz, 1H), 6.01 (s, 1H).

1. temperatureThe solution was cooled in an ice-water bath
2. extractionThe mixture was extracted twice with ethyl acetate
3. dry with materialthe combined extracts Were dried over Na2SO4
4. customThe solid were removed by filtration
5. distillationthe filtrate was distilled, first at atmospheric pressure
6. customto remove the solvent

ORD record

ord-e352429b213046aa992a3d931bb5e8e1

Source dataset

uspto-grants-1996_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05559242