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

HRID 520741Notes

Reaction equation

HRID 520741 reaction equation
C1CC1.[CH2:4]([O:6][C:7]([CH:9]1[CH2:11][C:10]1([C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1)[C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1)=[O:8])[CH3:5].OS(O)(=O)=O.[N:29]([O-])=[O:30].[Na+]>CC(O)=O.O>[CH2:4]([O:6][C:7]([C:9]1[CH2:11][C:10]([C:18]2[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=2)([C:12]2[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=2)[O:30][N:29]=1)=[O:8])[CH3:5]

Participants

7

Reactant 4

HCID 1118Sulfuric AcidHCID 6351CyclopropaneHCID 11300104HCID 11300104, compoundHCID 23668193Sodium Nitrite

Product 1

HCID 6451155Ethyl 5,5-diphenyl-2-isoxazoline-3-carboxylateYield 91%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 962WaterSolvent

Conditions

Temperature
18 °C

Procedure

The crude cyclopropane derivative, 2,2-diphenylcyclopropanyl carboxylate ethyl ester (generated through the reported one step procedure as a crude product in 107% yield) (1.14 g, 4.3 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 (0.33 g, 4.7 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. And the reactants were poured into an 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) in sequence. The washed ethereal solution was then dried over Na2SO4. After removing the desiccant, the ethereal solution was concentrated to furnish a thick oily crude product. The 1H NMR of the crude product showed that the reaction was clean and a virtual 100% yield. The thick oily crude product was stirred with 10 mL petrol to give a pale yellow solid 1.15 g, 91% yield (97% over yield in two steps based on diphenyl ketone hydrazine).

Workup

  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 crude product

Sources & evidence

ORD record
ord-a34e0e15cab442dba3102e0583952a42
Source dataset
uspto-grants-2016_05
Patent number
US09328074B2

Reaction notes

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