Hydrochloric Acid → (3R,8S)-3-[4-(3,4-dichloro-benzyloxy)-phenyl]-2,3,8,9-tetrahydro-6H-[1,4]dioxino[2,3-g]isoquinoline-7,8-dicarboxylic acid 7-tert-butyl ester

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Reaction Steps

(3R,8S)-3-[4-(3,4-Dichloro-benzyloxy)-phenyl]-2,3,8,9-tetrahydro-6H-[1,4]dioxino[2,3-g]isoquinoline-7,8-dicarboxylic acid 7-tert-butyl ester 8-methyl ester (1.0 g) was dissolved in 60 mL of THF-MeOH (1:4) and the mixture cooled on an ice bath. 2 N aqueous LiOH (5 eq.) was added and the mixture was stirred on ice for 15 minutes and then at room temperature for 14 hours. The pH of the mixture was adjusted to about 2 with 1N HCl and extracted with EtOAc. The organic layer was washed with brine, dried over sodium sulfate and concentrated. DCM was added and mixture was again concentrated (900 mg). LCMS: m/z 587.

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