Toluene → 2-(6-Methoxy-2-naphthyl)propionic acid

Participants

Reaction Conditions

Reaction Steps

Using the apparatus of the above Comparative Example, a toluene solution of 2-(6-methoxy-2-naphthyl)propionic acid (580.68 grams, 18.11 wt % solids, 91.64% S-enantiomer) was prepared from a sample of high chiral purity (S)-2-(6-methoxy-2-naphthyl)propionic acid, and racemic 2-(6-methoxy-2-naphthyl)propionic acid. The solution was heated to 85° C. Totals of 27.59 grams of 49.22 wt % NaOH and 7.822 grams of water were added. Two clear liquid phases were obtained. Water was stripped to 94.0° C. in 285 minutes. The total amount of water collected during the strip was 21.36 grams and the amount of toluene removed was 1.83 grams. The batch was agitated at 93.6°-94.0° C. for 15 minutes and cooled to 75° C. in 82 minutes and agitated at 75° C. for 60 minutes. Solids in the slurry settled well at the end of the 60-minute 75° C. ride. The centrifuge cake (sodium (S)-2-(6-methoxy-2-naphthyl)propionate monohydrate) was washed with 149.94 grams of hot (75° C.) toluene. Totals of 483.77 and 127.61 grams of mother liquor and wash liquor were recovered, respectively. The wet centrifuge cake weighed 75.02 grams which after drying for 8 hours at 80°-90° C. and under full vacuum yielded 67.29 grams of anhydrous sodium (S)-2-(6-methoxy-2-naphthyl)propionate. Chiral purities for the product and the mother liquor were found by analysis to be 99.03% S-enantiomer and 80.28% S-enantiomer, respectively.

Provenance & Evidence