Reaktion #5085

Reaktionsgleichung

carbonyl chloride

virginiamycin M1

pyridine

→

n-valerate

benzoate

Virginiamycin M1

Lösungsmittel

Methanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeto destroy excess reagent
2. 2
   SonstigeThe reaction mixture was partitioned between dichloromethane (3×5 ml) and saturated NaCl (aq) (50 ml)
3. 3
   TrocknenThe pooled organic layers were dried over anhydrous Na2SO4 and flash
4. 4
   Sonstigeevaporated to dryness (
5. 5
   Sonstigedry weight=0.63, 0.81, 1.0 and 1.4 g respectively)
6. 6
   SonstigePurification over a column of 50 g E

Vorschrift

The n-propionate, n-valerate, n-phenylacetate and benzoate derivatives of Virginiamycin M1 were prepared using the respective carbonyl chlorides. The respective carbonyl chloride (1.0 mmole) was added to a stirring solution of virginiamycin M1 (0.50 g, 0.95 mmole), pyridine (84 μl) and 4-dimethylaminopyridine (20 μg) at room temperature for 2 hours. Methanol (0.5 ml) was added to destroy excess reagent. The reaction mixture was partitioned between dichloromethane (3×5 ml) and saturated NaCl (aq) (50 ml). The pooled organic layers were dried over anhydrous Na2SO4 and flash evaporated to dryness (dry weight=0.63, 0.81, 1.0 and 1.4 g respectively). Purification over a column of 50 g E. Merck silica gel 60 (43-60 μm particle size) in 40-80% acetone/hexane stepwise gradients yielded 0.43, 0.33, 0.29 and 0.56 g of the respective esters.

Quelle