Реакция #1337100

Уравнение реакции

5-chloroindoline-2(R/S)-carboxylic acid methyl ester

N-t-butoxycarbonyl-2(S)-aminobutyric acid

diisopropylcarbodiimide

→

1-(N-t-Butoxycarbonyl-2(S)-aminobutyryl)-5-chloroindoline-2(S)-carboxylic acid methyl ester

Растворители

dichloromethane

Условия реакции

Обработка

1. 1
   Фильтрацияfiltered
2. 2
   ДругоеThe filtrate was evaporated under vacuum
3. 3
   Другоеto afford a brown solid which
4. 4
   Другоеwas purified by column chromatography on silica gel using 20:1 dichloromethane
5. 5
   ДругоеA white foam was obtained which
6. 6
   workup.ADDITIONthe mixture of two diastereomers
7. 7
   ДругоеThe two diastereomers were separated by column chromatography on silica gel using 7:3 petroleum spirit
8. 8
   Другоеdiethyl ether as eluent, and the pure (S,S) form was obtained as a white foam

Методика

To a solution of 5-chloroindoline-2(R/S)-carboxylic acid methyl ester (1.2 g, 5.69 mmol) and N-t-butoxycarbonyl-2(S)-aminobutyric acid (1.27 g, 6.25 mmol) dissolved in dried dichloromethane (10 ml) under nitrogen at 10° C., was added diisopropylcarbodiimide (0.98 ml, 6.30 mmol). The mixture was stirred at room temperature for 24 hours, then filtered. The filtrate was evaporated under vacuum to afford a brown solid which was purified by column chromatography on silica gel using 20:1 dichloromethane: diethyl ether as eluent. A white foam was obtained which was the mixture of two diastereomers. The two diastereomers were separated by column chromatography on silica gel using 7:3 petroleum spirit:diethyl ether as eluent, and the pure (S,S) form was obtained as a white foam.

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