(S)-Benzyl 3-[tert-butyldimethylsilyloxy]glutaramate → (S)-3-[tert-butyldimethylsilyloxy]glutaric acid monoamide

Participants

Reaction Steps

(S)-Benzyl 3-[tert-butyldimethylsilyloxy]glutaramate from example-3 (48.5 g) was dissolved in ethyl acetate (350 ml) and placed in a 500 ml glass pressure reactor with magnetic stirring. Palladium on charcoal catalyst (5%, 0.48 g) was added to this and the mixture was hydrogenated under 2.7 atmosphere of hydrogen for 4 hours. The pressure was released and the mixture was filtered. The catalyst was washed with 25 ml ethyl acetate and kept for reuse. The filtrate was mixed with water. The pH of the mixture was adjusted to 8.5 using 2.5 M aqueous ammonia under stirring. The aqueous phase was extracted once with MTBE. The clear aqueous phase was cooled to +5° C. and slowly acidified to pH 4.4 using conc HCl. A thick precipitate was formed at pH 4.8-5. The mixture was filtered and the solid was washed once with water and dried under reduced pressure to yield (S)-3-[tert-butyldimethylsilyloxy]glutaric acid monoamide.

Provenance & Evidence