2-Nitro-5-sulfanylbenzoic acid → (4R,4aS,12bS)-4a-hydroxy-9-methoxy-3-methyl-2,4,7a,13-tetrahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinolin-7-one

Participants

Reaction Steps

A sample of the oxycodone hydrochloride (579 mg, 1.65 mmol) was placed in an 8 mL reaction vial, to which was added 3.5 ml of the previously prepared solution of 5-mercapto-2-nitro-benzoic acid. The pH of the mixture was raised to 4.5 by addition of 100 mg/mL aqueous NaH2PO4 solution (0.47 mL), and a 1.0 ml aliquot was removed, diluted with pH 4.5, 0.01 M NaOAc/HOAc buffer solution (10 uL), and stirred. The remainder (2.5 mL) was reserved for separate spike experiments where known amounts of 14-hydroxycodeinone were added to the mixture. After 90 minutes, the pH was lowered to 2 with concentrated HCl (10 uL) and the suspension extracted with ethyl acetate (3×1 mL) by adding the solvent to the vial, capping it, and shaking vigorously. The organic layer was then completely removed from the vial by Pasteur pipet. The aqueous layer was analyzed by HPLC, wherein an analyte in the effluent stream was quantified from its absorbance at 325 nm. The 14-hydroxycodeinone content, and thus the sum of the 8-hydroxyoxycodone content and the 14-hydroxycodeinone content of the product of EXAMPLE 24, was 2.3 ppm as determined from a plot of the area under the 5-(oxycodone-8-sulfanyl)-2-nitro-benzoic acid peak per milligram of oxycodone analyzed versus the amount of 14-hydroxycodeinone added (ppm, i.e. microrams 14-hydroxycodeinone added per gram oxycodone) as shown in FIG. 11.

Provenance & Evidence