Reaction #2175446

Reaction equation

23-Azido-3,6,9,12,15,18,21-heptaoxatricosan-1-ol

DAST

→

4

Yield 24.4%

23-azido-1-fluoro-3,6,9,12,15,18,21-heptaoxatricosane

Yield 24.4%

Solvents

DCM

Conditions

Workup

1. 1
   Temperatureto warm to room temperature
2. 2
   workup.STIRRINGstirred for additional 20 hours
3. 3
   OtherThe excess of DAST was quenched with methanol (5 mL)
4. 4
   Otherthe solvents were subsequently evaporated at the reduced pressure
5. 5
   workup.DISSOLUTIONThe oily residue was dissolved in the water (3 mL)
6. 6
   OtherThe crude product was purified on semipreparative HPLC (System E)

Procedure

23-Azido-3,6,9,12,15,18,21-heptaoxatricosan-1-ol (500 mg, 1.26 mmol) was dissolved in DCM (2 mL) and cooled to −10° C. DAST (482 μL, 3.78 mmol) was added in portions to the cooled solution and the resulting mixture was stirred at −10° C. for 30 minutes then allowed to warm to room temperature and stirred for additional 20 hours. The excess of DAST was quenched with methanol (5 mL) and the solvents were subsequently evaporated at the reduced pressure. The oily residue was dissolved in the water (3 mL) and the pH was adjusted to 5 using NaHCO3. The crude product was purified on semipreparative HPLC (System E) to yield 122 mg (24%) of 4 as a yellowish oil. 1H NMR (500 MHz, CDCl3): δ 3.39 (t, J=5.0 Hz, 2H), 3.65-3.68 (m, 26H), 3.75 (dt, J=4.2 Hz, 29.6 Hz, 2H), 4.56 (dt, J=4.0 Hz, 47.5 Hz, 2H); 13C NMR (125.7 MHz, CDCl3): δ 50.8, 70.1, 70.4, 70.5, 70.7-70.8, 70.9, 83.2 (d, J=169 Hz); 19F NMR (470.6 MHz, CDCl3): 6-225.9; MS ESI (m/z): [M+H]+ calcd. for C16H33FO7N3, 398.2; found 398.0.

Source