Sulfuric Acid → Ethyl 5,5-diphenyl-2-isoxazoline-3-carboxylate

Temperatur

18 °C

The cyclopropane derivative, 2,2-diphenylcyclopropanyl carboxylate ethyl ester (1.0 g, 3.8 mmol) was dissolved in 4.0 mL AcOH at room temperature (18° C.). Into the solution was carefully added 2.0 mL concentrated H2SO4, followed by adding NaNO2 (0.29 g, 4.1 mmol, 1.1 eq) in several portions so that the reaction temperature did not excess 40° C. After addition, the reactants were stirred at room temperature (about 18° C.) for half an hour before the reactants were poured into iced water and extracted with diethyl ether (2×20 mL), the ethereal solutions were combined and washed with sat. NaHCO3 (2×20 mL), then water (20 mL) and brine (20 mL). The washed ethereal solution was then dried over Na2SO4. After removing the desiccant, the ethereal solution was concentrated to furnish a thick oily product. The 1H NMR of the crude product showed that the reaction was clean and the yield was virtually 100%. The thick oily crude product was stirred with 10 mL petrol to give a pale yellow solid 1.07 g, 97% yield.

1. customdid not excess 40° C
2. additionAfter addition
3. extractionextracted with diethyl ether (2×20 mL)
4. washwashed with sat. NaHCO3 (2×20 mL)
5. dry with materialThe washed ethereal solution was then dried over Na2SO4
6. customAfter removing the desiccant
7. concentrationthe ethereal solution was concentrated
8. customto furnish a thick oily product

ORD-Eintrag

ord-253698a3d095466595e86cd3bbade6b3

Quelldatensatz

uspto-grants-2016_05

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09328074B2