To obtain, in high yield, the optically pure subject compound by crystallizing an optically active N-protected-azetidine carboxylic acid, which excessively contains one isomer, from an organic solvent.
This method crystallizes (A) an optically active N-protected- azetidine carboxylic acid which excessively contains one isomer, shown by the formula [R is a (substituted) alkyl, (substituted) alkenyl, (alkylthio- substituted) amino, or the like; and * is asymmetric carbon, in (B) an organic solvent, preferably toluene or mixture thereof, e.g.; by cooling the saturated solution of the compound shown by the formula or adding it dropwise in a poor solvent, e.g. aliphatic hydrocarbon, preferably at -50 to 200°C. It is preferable to use 10 to 10,000 wt. parts of the component B per 100 wt. parts of the component A.
| JP2022064180 | HETEROCYCLIC COMPOUND |
| JP2022552445 | Arylmethylene Aromatic Compounds as Kv1.3 Potassium Shaker Channel Blockers |
| WO/2007/026207 | DIRECT AMINOLYSIS |
USHIO HIDEKI
KURIMOTO ISAO
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