Hydrochloric Acid → 4-[(4-(Hydroxydiphenylmethyl)-1-piperidinyl]-1-hydroxybutyl]-alpha,alpha-dimethylbenzeneacetic acid hydrochloride hydrate

Participants

Reaction Conditions

Reaction Steps

Place ethyl 4-[4-[4-(hydroxydiphenylmethyl)-1-piperidinyl]-1-oxobutyl]-α,α-dimethylbenzeneacetate, hydrochloride (60.01 g, 0.106 mol) in a 1-L three necked round-bottom flask and fit the flask with a mechanical stirrer, a Claisen head, a thermometer and a reflux condenser with a nitrogen bubbler on top. Add methanol (300 mL) and turn the stirrer on. Dilute the slurry with water (6 mL) and heat to 52–54° C. over 15–20 minutes. Hold at 52° C. for 2 hours and then add 50% sodium hydroxide (42.54 g, 0.532 mol). Heat at 73° C. for approximately 1 hour, 45 minutes, cool to less than 35° C. using a water bath and then add sodium borohydride (2.02 g, 0.0534 mol). Stir overnight at 35° C., treat with acetone (15.5 mL) and stir for 2 hours at 35° C. Acidify the mixture to a pH of 1.85 with 28% hydrochloric acid (75.72 g), dilute with water (282 mL), stir for about 30 minutes and cool over about 2 hours to −15° C. Filter the solids off and wash with water (2×75 mL) and ethyl acetate (2×75 mL). Vacuum dry the solid and allow to stand for 2 days to give 4-[4-[4-(hydroxydiphenylmethyl)-1-piperidinyl]-1-hydroxybutyl]-α,α-dimethylbenzeneacetic acid hydrochloride hydrate (Form II) (57.97 g, 91.5%) as a fine powder.

Provenance & Evidence