تفاعل #167090

معادلة التفاعل

(S)-benzyl 1-((S)-2-(methoxycarbonylamino)-3-methylbutanoyl)-4-oxopyrrolidine-2-carboxylate

p-toluene sulfonic acid monohydride

ethylene glycol

→

(S)-benzyl 7-((S)-2-(methoxycarbonylamino)-3-methylbutanoyl)-1,4-dioxa-7-azaspiro[4.4]nonane-8-carboxylate

المذيبات

toluene

ظروف التفاعل

المعالجة

1. 1
   درجة الحرارةthe mixture was refluxed for 18 hours
2. 2
   أخرىremoving the generated byproduct water with a Dean-Stark apparatus
3. 3
   workup.ADDITIONThe crude mixture was then diluted with ethyl acetate
4. 4
   غسيلwashed
5. 5
   تجفيفdried over sodium sulfate
6. 6
   تركيزconcentrated down on rotovap
7. 7
   أخرىThe crude residue was then purified on normal phase column chromatography with 5% MeOH/DCM

الإجراء التجريبي

(S)-benzyl 1-((S)-2-(methoxycarbonylamino)-3-methylbutanoyl)-4-oxopyrrolidine-2-carboxylate (2.45 g, 6.51 mmol) in a round bottom flask was dissolved in anhydrous toluene (200 mL) and p-toluene sulfonic acid monohydride (124 mg, 0.1 mmol) and ethylene glycol (808 mg, 13.02 mmol) were added and the mixture was refluxed for 18 hours, removing the generated byproduct water with a Dean-Stark apparatus. The crude mixture was then diluted with ethyl acetate and washed, respectively, with 10% citric acid, saturated ammonium chloride, 10% sodium carbonate and finally with brine. The organic layers were combined and dried over sodium sulfate and concentrated down on rotovap. The crude residue was then purified on normal phase column chromatography with 5% MeOH/DCM. (2.3 g, 84%)

المصدر