Reaction #3133

Reaction equation

hydrochloric acid

(11R,12S,13E,15S)-9-butyryloxy-11,15-bis(tert-butyldimethylsiloxy)-7-thiaprosta-8,13-dienoic acid

isobutyl chloroformate

ammonium hydroxide

→

(11R,12S,13E,15S)-9-butyryloxy-11,15-bis(tert-butyldimethylsiloxy)-7-thiaprosta-8,13-dienamide

Yield 84.0%

Solvents

ethyl acetate

methylene chloride

triethylamine

Conditions

Workup

1. 1
   workup.STIRRINGthe mixture was stirred overnight
2. 2
   ExtractionThe desired substance was extracted from the mixture by ethyl acetate
3. 3
   Extractionextract
4. 4
   Washwas successively washed by saturated sodium hydrogen carbonate and saturated sodium chloride solution
5. 5
   ConcentrationThis solution was concentrated under reduced pressure
6. 6
   Otherwas purified by silica gel column chromatography (45% ethyl acetate/hexane)

Procedure

A methylene chloride (3 ml) solution of (11R,12S,13E,15S)-9-butyryloxy-11,15-bis(tert-butyldimethylsiloxy)-7-thiaprosta-8,13-dienoic acid (201 mg) was cooled to -40° C., then isobutyl chloroformate (47 μl) and triethylamine (63 μl) were added to the solution which was then stirred as is at -40° C. for 30 minutes. Further 1 ml of 30% ammonium hydroxide solution was added and the mixture was stirred overnight while raising the temperature to room temperature. The reaction solution was diluted by ethyl acetate then was neutralized by dilute hydrochloric acid. The desired substance was extracted from the mixture by ethyl acetate and extract was successively washed by saturated sodium hydrogen carbonate and saturated sodium chloride solution. This solution was concentrated under reduced pressure, then was purified by silica gel column chromatography (45% ethyl acetate/hexane) to obtain (11R,12S,13E,15S)-9-butyryloxy-11,15-bis(tert-butyldimethylsiloxy)-7-thiaprosta-8,13-dienamide (169 mg, 84%).

Source