1954 年 74 巻 12 号 p. 1293-1295
In order to generalize the new method for N-monoalkylation of β-aminoalcohols (Pharm. Bull. (Japan), 1, 325 (1953)). dl-ψ-5-phenyl-2, 4-dimethyloxazoline was synthesized by the treatment of N-acetyl-dl-ψ-norephedrine with conc. surfuric acid. The former was reacted with methylating agents to give the postulated dl-ψ-5-phenyl-2, 3, 4-trimeth-yloxazolinium salts as oily products which were very sensitive to moisture and rapidly added one mole of water to form the salt of O-acetyl-dl-ψ-ephedrine by retention. The oily product was boiled, immediately after formation, in dry acetic acid-sodium acetate, avoiding moisture, and gave O, N-diacetyl-dl-ephedrine by inversion. Thus it was found that the amine was not substituted by more than one alkyl group and that the retention or inversion of the configuration of the resultant compound could be controlled at will by the treatment either in wet or dry conditions.