tert-Butanol → Carbamic acid, N-(2,2-dimethyl-3-oxocyclobutyl)-, 1,1-dimethylethyl ester

HRID 1749432Notes

Reaction equation

HRID 1749432 reaction equation
[CH3:1][C:2]1([CH3:10])[C:5](=[O:6])[CH2:4][CH:3]1C(O)=O.C([N:13]([CH2:16]C)CC)C.C1(P(N=[N+]=[N-])(C2C=CC=CC=2)=[O:25])C=CC=CC=1.[C:35]([OH:39])([CH3:38])([CH3:37])[CH3:36].C(=O)(O)[O-].[Na+]>C1(C)C=CC=CC=1.C(OCC)(=O)C>[CH3:10][C:2]1([CH3:1])[C:5](=[O:6])[CH2:4][CH:3]1[NH:13][C:16](=[O:25])[O:39][C:35]([CH3:38])([CH3:37])[CH3:36]

Participants

8

Reactant 5

HCID 6386tert-ButanolHCID 8471TriethylamineHCID 199401P,P-Diphenylphosphinic azideHCID 2760812,2-dimethyl-3-oxocyclobutanecarboxylic acidHCID 516892Sodium Bicarbonate

Product 1

HCID 84679804Carbamic acid, N-(2,2-dimethyl-3-oxocyclobutyl)-, 1,1-dimethylethyl esterYield 16%

Reagents, catalysts & solvents 2

HCID 1140TolueneSolventHCID 8857Ethyl AcetateSolvent

Conditions

Temperature
100 °C

Procedure

To a solution of 2,2-dimethyl-3-oxocyclobutanecarboxylic acid (1.0 equiv.) and triethylamine (1.5 equiv.) in toluene (0.2 M) was added diphenylphosphoryl azide (2.0 equiv.) slowly under ice-water bath. Then the mixture was stirred at 100° C. for 4 h. The reaction mixture was cooled down to room temperature, and tert-butanol (2.2 equiv.) was added. The resulting mixture was refluxed for 15 h. After the mixture cooled down, an aqueous solution of sodium bicarbonate and ethyl acetate were added. The organic layer was separated and the aqueous solution was extracted with ethyl acetate. The combined organic layer was washed with aqueous solution of sodium bicarbonate and brine, dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under vacuum, the residue was purified by silica gel column chromatography (7% ethyl acetate in petroleum ether) to afford the title product (16% yield). 1H NMR (300 MHz, CDCl3) δ (ppm) 4.81-4.70 (m, 1H), 4.05-3.93 (m, 1H), 3.37 (dd, J1=18.0 Hz, J2=9.0 Hz, 1H), 2.89 (dd, J1=18.0 Hz, J2=6.9 Hz, 1H), 1.48 (s, 9H), 1.28 (s, 3H), 1.13 (s, 3H).

Workup

  1. temperatureThe reaction mixture was cooled down to room temperature
  2. temperatureThe resulting mixture was refluxed for 15 h
  3. temperatureAfter the mixture cooled down
  4. customThe organic layer was separated
  5. extractionthe aqueous solution was extracted with ethyl acetate
  6. washThe combined organic layer was washed with aqueous solution of sodium bicarbonate and brine
  7. dry with materialdried over anhydrous sodium sulfate
  8. filtrationfiltered
  9. concentrationThe filtrate was concentrated under vacuum
  10. customthe residue was purified by silica gel column chromatography (7% ethyl acetate in petroleum ether)

Sources & evidence

ORD record
ord-7a6df654ffc642d987c790efc2a14c84
Source dataset
uspto-grants-2015_10
Patent number
US09156798B2

Reaction notes

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