Phenylephrine hydrochloride, SLV-325, Incostop, Neo-Synephrine hydrochloride, Nostril, Mydfrin, Biomydrin, Alcon Efrin

(-)-3-[1(R)-Hydroxy-2-(methylamino)ethyl]phenol hydrochloride

61-76-7, 59-42-7 (free base)

C9-H13-N-O2.Cl-H

203.6676

Solvay (Marketer), SLA Pharma (Licensee)

Anorectal Disorders, Treatment of, GASTROINTESTINAL DRUGS

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Org Process Res Dev

A practical synthesis of (R)-(-)-phenylephrine hydrochloride

3-Hydroxybenzaldehyde (I) was protected as the methoxyethoxymethyl ether derivative (II) by treatment with methoxyethoxymethyl chloride and diisopropyl ethyl amine. Subsequent condensation of (II) with dimethyloxosulfonium methylide, generated from oxosulfonium salt (III) and NaH, gave rise to the racemic epoxide (IV). Kinetic resolution by hydrolysis with (R,R)-N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminocobalt (III) acetate complex provided the (S)-diol (V) along with the unreacted (R)-epoxide (VI), which were separated by column chromatography. Opening of the desired (R)-epoxide (VI) with methanolic methylamine gave amino alcohol (VII). Finally, removal of the methoxyethoxymethyl group by refluxing in methanolic HCl furnished the title compound.

Gurjar, M.K.; et al.

Gurjar, M.K.; et al.; A practical synthesis of (R)-(-)-phenylephrine hydrochloride. Org Process Res Dev 1998, 2, 6, 422

Org Process Res Dev1998,2,(6):422

Synthesis of 070250: 3-Hydroxybenzaldehyde (I) was protected as the methoxyethoxymethyl ether derivative (II) by treatment with methoxyethoxymethyl chloride and diisopropyl ethyl amine. Subsequent condensation of (II) with dimethyloxosulfonium methylide, generated from oxosulfonium salt (III) and NaH, gave rise to the racemic epoxide (IV). Kinetic resolution by hydrolysis with (R,R)-N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminocobalt (III) acetate complex provided the (S)-diol (V) along with the unreacted (R)-epoxide (VI), which were separated by column chromatography. Opening of the desired (R)-epoxide (VI) with methanolic methylamine gave amino alcohol (VII). Finally, removal of the methoxyethoxymethyl group by refluxing in methanolic HCl furnished the title compound. (Scheme 07025001a)