C - Chemistry – Metallurgy – 12 – P
Patent
C - Chemistry, Metallurgy
12
P
C12P 41/00 (2006.01) C12P 7/42 (2006.01) C12P 7/62 (2006.01)
Patent
CA 2065433
R- and S-1-Phenyl-1,3-propanediol, each of high optical purity, were prepared by a chemoenzymatic sequence starting with ethyl benzoylacetate. The first step was a catalytic hydrogenation of the .beta.-ketoester conducted at room temperature. The en- zymatic hydrolysis of the resulting hydroxyester proceeded in a facile manner using a commercial preparation of the lipase from Pseudomonas fluorescens. The enzymatic hydrolysis proceeded at a moderate rate (350 mg lipase/0.10 mol of racemic ester re- quired a 20-hour reaction time with an enantiomeric rate ratio (E value) of 36). The hydrolysis was run to 45-50 % conversion to afford isolated S-3-phenyl-3-hydroxypropionic acid of 85-90 % ee after separation from the residual ester (aqueous base extrac- tion). The optical purity of the hydroxy acid was determined by conversion to the methyl ester (CH3I, KHCO3, acetone) and de- rivatization with S-MTPA-CI, and ?H NMR analysis. A single recrystallization of the isolated acid afforded optically pure (>98 % ee) S-3-phenyl-3-hydroxypropionic acid in an overall 36% yield from the racemic ester. The acid was reduced with bo- rane in THF to afford optically pure S-diol in 97 % yield after crystallization. The overall sequence proceeded in 34 % total yield from racemic ester with an additional 45-55 % recovered as the antipodal ester. This antipodal ester is obtained in 85-95 % ee, and the corresponding hydroxy-acid was readily obtained (NaOH, CH3OH/H2O) and recrystallized to optical purity. Reduction then afforded R-1-phenyl-1,3-propanediol in 30 % to overall yield from racemic ester.
Eastman Chemical Company
Gowling Lafleur Henderson Llp
LandOfFree
Synthesis of aryl alkanediols having high optical purity does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Synthesis of aryl alkanediols having high optical purity, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Synthesis of aryl alkanediols having high optical purity will most certainly appreciate the feedback.
Profile ID: LFCA-PAI-O-1455057