Penicillin G → (S)-ethyl-3-(phenoxyacetamido)-5-(trimethylsilyl)-4-pentynoate

Participants

Reaction Steps

Racemic ethyl 3-(phenoxyacetamido)-5-(trimethylsilyl)-4-pentynoate (1g) was suspended in phosphate buffer (250 mL, 0.01 molar, prepared from 0.1 molar pH 7.24 solution obtained from sigma). The pH of the solution was adjusted 7.8 using dilute sodium hydroxide. Under slow stirring, 100 units of immobilized penicillin G acylase (Boehringer-Mannheim) was added. The reaction mixture was stirred at room temperature for 48 hours. The reaction mixture was extracted with ethyl acetate (75 mL×3). The organic extracts were combined, dried over sodium sulfate, filtered and evaporated to dryness to give the desired amide, (S)-ethyl-3-(phenoxyacetamido)-5-(trimethylsilyl)-4-pentynoate. The immobilized enzyme was filtered off from the aqueous phase using Whatman No.1 filter paper. The pH of the aqueous phase was adjusted to 8.0 using dilute sodium hydroxide, and extracted with ethyl acetate (75 mL×3). The extracts were combined, dried over sodium sulfate, filtered and evaporated to dryness to give the desired amine, (R)-ethyl-3-amino-5-(trimethylsilyl)-4-pentynoate.

Provenance & Evidence