Reaktion #65537

Reaktionsgleichung

(2S, 4R)-4-methanesulfonyloxy-2-(4-methylsemicarbazidocarbonyl)-1- (4-nitrobenzyloxycarbonyl)pyrrolidine

sulfuric acid

ammonia water

→

(2S, 4R)-4-methanesulfonyloxy-2-{5-(methylamino)-1,3,4-thiadiazol-2-yl }-1-(4-nitrobenzyloxycarbonyl)pyrrolidine

Reaktionsbedingungen

Aufarbeitung

1. 1
   Extraktionextracted with dichloromethane (100 ml)
2. 2
   Trocknendried over magnesium sulfate
3. 3
   Einengenconcentrated under reduced pressure
4. 4
   Sonstigeto give a syrup
5. 5
   Wascheneluted with a mixture of methanol and chloroform (1:99,V/V)

Vorschrift

A suspension of (2S, 4R)-4-methanesulfonyloxy-2-(4-methylsemicarbazidocarbonyl)-1- (4-nitrobenzyloxycarbonyl)pyrrolidine (2.00 g) in concentrated sulfuric acid (20 ml) was stirred at 0°-5° C. for 3 hours. The reaction mixture was poured into ice-water (200 ml), adjusted to pH 9 with concentrated ammonia water, extracted with dichloromethane (100 ml), dried over magnesium sulfate and concentrated under reduced pressure to give a syrup. The syrup was subjected to a column chromatography on silica gel (20 g) and eluted with a mixture of methanol and chloroform (1:99,V/V) to give (2S, 4R)-4-methanesulfonyloxy-2-{5-(methylamino)-1,3,4-thiadiazol-2-yl }-1-(4-nitrobenzyloxycarbonyl)pyrrolidine (1.94 g).

Quelle