Sumitomo Dainippon Pharma Co., Ltd.

Dainippon Sumitomo Pharma Co., Ltd.

Toshikazu Yagi

Satoshi Suzuki

Kazuki Hashimoto

Hiroto Tatamidani

Masanori Itoh

Koji Koyama

The invention addresses the problem of providing a method for producing 2-acetyl-4H,9H-naphtho[2,3-b]furan-4,9-dione that is suited to industrial production. The invention provides a method for producing 2-acetyl-4H,9H-naphtho[2,3-b]furan-4,9-dione by reacting 3-bromo-3-buten-2-one and 2-hydroxy-1,4-naphthoquinone in the presence of a solvent, then obtaining crystals of 2-acetyl-4H,9H-naphtho[2,3-b]furan-4,9-dione by adding an alcohol-based solvent and/or water to the reaction system, and treating the crystals by using a specific adsorbent in the presence of a solvent.

Method for producing 2-acetyl-4H,9H-naphtho[2,3-b]furan-4,9-dione

Method for producing 2-acetyl-4H,9H-naphtho[2,3-B]furan-4,9-dione

The present invention provides a process for producing Droxidopa or a pharmaceutically acceptable salt thereof comprising a step of reacting threo-N-phthaloyl-3-(3,4-dihydroxyphenyl)-L-serine represented by the formula (1) with methylamine, whereby a process for producing threo-3-(3,4-dihydroxyphenyl)-L-serine (common name: Droxidopa), which is useful as an agent for treatment of peripheral orthostatic hypotension or an agent for treatment of Parkinson's disease, with high production efficiency and without requiring troublesome operations. 

Process for producing threo-3-(3,4-dihydroxyphenyl)-L-serine

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Mie, Japan

Toshikazu Yagi