Acetic Acid → 5(S)-[5-Benzyloxy-1(S)-tert-butoxycarbonylamino-3,3-dimethyl-pentyl]-2-oxotetrahydrofuran

Participants

Reaction Steps

5.52 g of the ethyl 9-benzyloxy-5(S)-tert-butoxycarbonylamino-4(R,S)-hydroxy-7,7-dimethyl-nonanoate obtained as the crude product are refluxed in 100 ml of toluene and 4 ml of glacial acetic acid at 110° C. under argon for 4.5 h. After the reaction mixture has cooled, it is diluted with ethyl acetate and worked up in the customary manner. The crude product is purified by chromatography over silica gel (mobile phase B), the two 5(S) and 5(R) stereoisomers being separated. This gives the pure title compound (diastereomer I) as a yellowish oil: Rf (B)=0.26; FAB-MS: (M+H)+ =406; and diastereomer II: Rf (B)=0.22.

Provenance & Evidence