PURPOSE: To economically, simply and efficiently obtain the titled compound useful as an antihypertensive, by reacting (R)-2-amino-4-phenyl lactic acid which is readily available and used as a raw material with nitrous acid in an aqueous medium in the presence of a mineral acid.
CONSTITUTION: (R)-2-Amino-4-phenyl lactic acid used as a raw material is reacted with nitrous acid (NHO2) in an aqueous medium in the presence of a mineral acid, preferably hydrochloric acid to provide the aimed compound. Reaction with the above-mentioned nitrous acid is carried out normally at 20W60°C, preferably 30W50°C. Further more, acid concentration in the above- mentioned reaction is preferably about 0W3 normally in concentration of free acid in the reaction system other than acid having equivalent required for protonating amino group of (R)-2-amino-4-phenyl lactic acid. In the amount of the nitrous acid added, 1W1.5 equivalent based on the above-mentioned raw material is required and the addition of the nitrous acid is preferably carried out by gradually and continuously adding.
YAMADA KAZUHIKO
FUKAE MASABUMI
| JP40004808A |
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