L-THREO-3-(3,4-DIHYDROXYPHENYL)-N-METHYLSERINE IN ANHYDROUS CRYSTAL FORM

PURPOSE:The titled compound in an anhydrous crystal form, obtained by treating a hydrate, solvated substance, etc., of the titled compound with a heated solvent, useful for treating diseases in central nervous systems and having uniform quality and good stability as well as novel crystal structure. CONSTITUTION:Hydrate, solvates substance, amorphous powder or L-threo-3-(3,4- dihydroxyphenyl)-N-methylserine or a mixture thereof is treated with a solvent, e.g. water, methanol or acetonitrile, heated to 40 deg.C-the boiling point of the solvent, preferably 50-70 deg.C for 15min-10hr to afford the aimed compound having a novel crystal structure. The above-mentioned compound has lattice spacings (d-value) and relative intensity (I) of an X-ray diffraction pattern [X ray source; CuKalpha (Ni filter used), output; 35kW 15mA, X-ray wavelength used; lambda=1.5418Angstrom ] shown in the table.