Reaction #355762

Reaction equation

azithromycin

NaHCO3

5-bromovaleric acid

triethylamine

pivaloyl chloride

→

pure product

Yield 108.6%

Cladinose

Yield 108.6%

Solvents

CH2Cl2

CH2Cl2

Conditions

Workup

1. 1
   workup.STIRRINGThe reaction mixture was stirred for three days at room temperature
2. 2
   Otherthe layers were separated
3. 3
   ExtractionThe aqueous layer was twice more extracted with 40 ml of CH2Cl2
4. 4
   WashThe combined organic extracts were washed with a saturated NaCl solution
5. 5
   Dryingdried over K2CO3
6. 6
   Otherevaporated in a rotary evaporator
7. 7
   OtherThe obtained oily product was purified on a silica gel column (eluant: CH2Cl2:CH3OH:NH4OH=90:9:1.5)

Procedure

To a solution of 5-bromovaleric acid (1.282 g; 7.07 mmole) in dry CH2Cl2 (10 ml), 1 ml (7.23 mmole) of triethylamine, 868 mg (7.10 mmole) of 4-dimethyl-aminopyridine and 0.940 ml (7.63 mmole) of pivaloyl chloride were added. The solution was stirred for 2 hours at room temperature in a flow of argon and then a solution of azithromycin (2 g; 2.67 mmole) in 10 ml of dry CH2Cl2 was added. The reaction mixture was stirred for three days at room temperature. Subsequently, 60 ml of saturated NaHCO3 solution were added to the reaction mixture and the layers were separated. The aqueous layer was twice more extracted with 40 ml of CH2Cl2. The combined organic extracts were washed with a saturated NaCl solution, dried over K2CO3 and evaporated in a rotary evaporator. The obtained oily product was purified on a silica gel column (eluant: CH2Cl2:CH3OH:NH4OH=90:9:1.5). 511 mg of the pure product were obtained. MS(ES+): 912 (MH+)

Source